Massive style revision and version update

1 files changed, 1094 insertions, 1060 deletions

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index a14e342..c9bd082 100644
--- a/README.md
+++ b/README.md
@@ -1,193 +1,172 @@
-This is a guide to using [YubiKey](https://www.yubico.com/faq/yubikey/) as a [SmartCard](https://security.stackexchange.com/questions/38924/how-does-storing-gpg-ssh-private-keys-on-smart-cards-compare-to-plain-usb-drives) for storing GPG encryption and signing keys.
+This is a guide to using [YubiKey](https://www.yubico.com/faq/yubikey/) as a [SmartCard](https://security.stackexchange.com/questions/38924/how-does-storing-gpg-ssh-private-keys-on-smart-cards-compare-to-plain-usb-drives) for storing GPG encryption, signing and authentication keys, which can be used for SSH.
 
-An authentication key can also be created for SSH and used with [gpg-agent](https://unix.stackexchange.com/questions/188668/how-does-gpg-agent-work/188813#188813).
-
-Keys stored on a smartcard like YubiKey are non-exportable (as opposed to keys that are stored on disk) and are convenient for everyday use. Instead of having to remember and enter passphrases to unlock SSH/GPG keys, YubiKey needs only a physical touch after being unlocked with a PIN code - and all signing and encryption operations happen on the card, rather than in OS memory.
-
-Programming YubiKey for GPG keys still lets you use its two slots - [OTP](https://www.yubico.com/faq/what-is-a-one-time-password-otp/) and [static password](https://www.yubico.com/products/services-software/personalization-tools/static-password/) modes, for example.
+Keys stored on YubiKey are non-exportable (as opposed to file-based keys that are stored on disk) and are convenient for everyday use. Instead of having to remember and enter passphrases to unlock SSH/GPG keys, YubiKey needs only a physical touch after being unlocked with a PIN code. All signing and encryption operations happen on the card, rather than in OS memory.
 
 **New!** [Purse](https://github.com/drduh/Purse) is a password manager which can integrate with GPG on YubiKey.
 
 If you have a comment or suggestion, please open an [issue](https://github.com/drduh/YubiKey-Guide/issues) on GitHub.
 
-1. [Purchase YubiKey](#1-purchase-yubikey)  
-2. [Install required software](#2-install-required-software)  
-  2.1 [Install - Linux](#21-install---linux)  
-  2.2 [Install - macOS](#22-install---macos)  
-  2.3 [Install - Windows](#23-install---windows)  
-3. [Creating keys](#3-creating-keys)  
-  3.1 [Create temporary working directory for GPG](#31-create-temporary-working-directory-for-gpg)  
-  3.2 [Create configuration](#32-create-configuration)  
-  3.3 [Create master key](#33-create-master-key)  
-  3.4 [Save Key ID](#34-save-key-id)  
-  3.5 [Create subkeys](#35-create-subkeys)  
-    3.5a [Signing key](#35a-signing-key)  
-    3.5b [Encryption key](#35b-encryption-key)  
-    3.5c [Authentication key](#35c-authentication-key)  
-  3.6 [Check your work](#36-check-your-work)  
-  3.7 [Export keys](#37-export-keys)  
-    3.7a [Linux/macOS](#37a-linuxmacos)  
-    3.7b [Windows](#37b-windows)  
-  3.8 [Backup everything](#38-backup-everything)  
-    3.8a [Linux/macOS](#38a-linuxmacos)  
-    3.8b [Windows](#38b-windows)  
-  3.9 [Configure YubiKey](#39-configure-yubikey)  
-    3.9a [Linux/macOS](#39a-linuxmacos)  
-    3.9b [Windows](#39b-windows)  
-  3.10 [Configure smartcard](#310-configure-smartcard)  
-    3.10a [Change PINs](#310a-change-pins)  
-    3.10b [Set card information](#310b-set-card-information)  
-  3.11 [Transfer keys](#311-transfer-keys)  
-    3.11a [Signature key](#311a-signature-key)  
-    3.11b [Encryption key](#311b-encryption-key)  
-    3.11c [Authentication key](#311c-authentication-key)  
-  3.12 [Check your work](#312-check-your-work)  
-  3.13 [Export public key](#313-export-public-key)  
-  3.14 [Finish](#314-finish)  
-4. [Using keys](#4-using-keys)  
-  4.1 [Create GPG configuration](#41-create-gpg-configuration)  
-  4.2 [Import public key](#42-import-public-key)  
-  4.3 [Insert YubiKey](#43-insert-yubikey)  
-  4.4 [GnuPG](#44-gnupg)  
-    4.4a [Trust master key](#44a-trust-master-key)  
-    4.4b [Encryption](#44b-encryption)  
-    4.4c [Decryption](#44c-decryption)  
-    4.4d [Signing](#44d-signing)  
-    4.4e [Verifying signature](#44e-verifying-signature)  
-  4.5 [SSH - Linux/Mac](#45-ssh---linuxmacos)  
-    4.5a [A Note on GPG Agent's SSH Agent](#45a-a-note-on-gpg-agents-ssh-agent)  
-    4.5b [Update configuration](#45b-update-configuration)  
-    4.5c [Replace ssh-agent with gpg-agent](#45c-replace-ssh-agent-with-gpg-agent)  
-    4.5d [Copy public key to server](#45d-copy-public-key-to-server)  
-    4.5e [Connect with public key authentication](#45e-connect-with-public-key-authentication)  
-    4.5f [(Optional) Import SSH Keys to `gpg-agent`](#45f-optional-import-ssh-keys-to-gpg-agent)  
-  4.6 [SSH - Windows](#46-ssh---windows)  
-    4.6a [GitHub](#46a-github)  
-  4.7 [Requiring touch to authenticate](#47-requiring-touch-to-authenticate)  
-  4.8 [OpenBSD](#48-openbsd)  
-5. [Troubleshooting](#5-troubleshooting)  
-  5.1 [Yubikey OTP Mode and cccccccc....](#51-yubikey-otp-mode-and-cccccccc)  
-6. [References and other work](#6-references-and-similar-work)  
+- [Purchase YubiKey](#purchase-yubikey)
+- [Live image](#live-image)
+- [Required software](#required-software)
+  - [Entropy](#entropy)
+- [Creating keys](#creating-keys)
+- [Master key](#master-key)
+- [Sub-keys](#sub-keys)
+  - [Signing](#signing)
+  - [Encryption](#encryption)
+  - [Authentication](#authentication)
+- [Verify keys](#verify-keys)
+- [Export keys](#export-keys)
+- [Backup keys](#backup-keys)
+- [Configure YubiKey](#configure-yubikey)
+- [Configure Smartcard](#configure-smartcard)
+  - [Change PIN](#change-pin)
+  - [Set information](#set-information)
+- [Transfer keys](#transfer-keys)
+  - [Signing](#signing-1)
+  - [Encryption](#encryption-1)
+  - [Authentication](#authentication-1)
+- [Verify card](#verify-card)
+- [Export public key](#export-public-key)
+- [Cleanup](#cleanup)
+- [Using keys](#using-keys)
+- [Import public key](#import-public-key)
+  - [Trust master key](#trust-master-key)
+- [Insert YubiKey](#insert-yubikey)
+- [Encryption](#encryption-2)
+- [Decryption](#decryption)
+- [Signing](#signing-2)
+- [Verifying signature](#verifying-signature)
+- [SSH](#ssh)
+  - [Create configuration](#create-configuration)
+  - [Replace agents](#replace-agents)
+  - [Copy public key](#copy-public-key)
+  - [(Optional) Save public key for identity file configuration](#optional-save-public-key-for-identity-file-configuration)
+  - [Connect with public key authentication](#connect-with-public-key-authentication)
+  - [Touch to authenticate](#touch-to-authenticate)
+  - [Import SSH keys](#import-ssh-keys)
+  - [GitHub](#github)
+  - [OpenBSD](#openbsd)
+  - [Windows](#windows)
+- [Troubleshooting](#troubleshooting)
+- [Notes](#notes)
+- [Similar work](#similar-work)
+
+# Purchase YubiKey
+
+YubiKey 4 has support for **4096 bit** RSA keys in OTP+CCID mode, whereas NEO are [limited](https://www.yubico.com/products/yubikey-hardware/compare-yubikeys/) to **2048 bit** RSA keys.
+
+Consider purchasing a pair of keys and programming both in case of loss or damage to one of them.
+
+# Live image
+
+It is recommended to generate cryptographic keys and configure YubiKey from a secure environment. One way to do is by downloading and booting to a [Debian Live](https://www.debian.org/CD/live/) or [Tails](https://tails.boum.org/index.en.html) image loaded from a USB drive into memory.
+
+Download the latest image and verify its integrity:
 
-# 1. Purchase YubiKey
+```
+$ curl -LfO https://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid/debian-live-9.5.0-amd64-xfce.iso
 
-https://www.yubico.com/products/yubikey-hardware/
+$ curl -LfO https://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid/SHA512SUMS
 
-Consider purchasing a pair (or more) and programming both in case of loss or damage to one of them.
+$ !!.sign
 
-# 2. Install required software
+$ gpg SHA512SUMS.sign
+[...]
+gpg: Good signature from "Debian CD signing key <debian-cd@lists.debian.org>" [unknown]
+[...]
 
-These instructions are current to Debian 9 using YubiKey 4 - with support for **4096 bit** RSA keys - in OTP+CCID mode, using GPG version 2.2. Note, older YubiKeys like the Neo are [limited](https://www.yubico.com/products/yubikey-hardware/compare-yubikeys/) to **2048 bit** RSA keys.
+$ grep $(sha512sum debian-live-9.5.0-amd64-xfce.iso) SHA512SUMS
+d2b0fe266ef809943f24b71f6a7c1c7a1645a2ee0b51e71bb05625ca84f16904a8889287d580fcb5d8ff1152785f90ffdb1621733bbb148431155478b0006114  debian-live-9.5.0-amd64-xfce.iso
+```
 
-For improved security, use a live GNU/Linux distribution like [Tails](https://tails.boum.org/index.en.html) or [Debian Live](https://www.debian.org/CD/live/) - with no connection to outgoing Internet.
+Mount a USB drive and copy the image over to it:
 
-## 2.1 Install - Linux
+```
+$ sudo dd if=debian-live-9.5.0-amd64-xfce.iso of=/dev/sdc bs=4M
 
-You will need to install the following software:
+$ sync
+```
 
-    $ sudo apt-get install -y \
-        gnupg2 gnupg-agent pinentry-curses scdaemon pcscd yubikey-personalization libusb-1.0-0-dev
+Shut down the computer and disconnect hard drives and any unnecessary peripherals.
 
-You may also need to download and install more recent versions of [yubikey-personalization](https://developers.yubico.com/yubikey-personalization/Releases/) and [yubico-c](https://developers.yubico.com/yubico-c/Releases/):
+Plug in the USB drive and boot to the live image. Configure networking to continue.
 
-```
-    $ curl -LfsOv https://developers.yubico.com/yubikey-personalization/Releases/ykpers-1.19.0.tar.gz
+# Required software
 
-    $ !!.sig
-    curl -LfsOv https://developers.yubico.com/yubikey-personalization/Releases/ykpers-1.19.0.tar.gz.sig
+```
+$ sudo apt-get update
 
-    $ gpg yk*sig
-    gpg: assuming signed data in 'ykpers-1.19.0.tar.gz'
-    gpg: Signature made Tue Apr 24 01:29:05 2018 PDT
-    gpg:                using RSA key 0xBCA00FD4B2168C0A
-    gpg: Can't check signature: No public key
+$ sudo apt-get install -y \
+     curl gnupg2 gnupg-agent \
+     cryptsetup scdaemon pcscd \
+     yubikey-personalization
+```
 
-    $ gpg --recv 0xBCA00FD4B2168C0A
-    gpg: key 0xBCA00FD4B2168C0A: public key "Klas Lindfors <klas@yubico.com>" imported
-    gpg: marginals needed: 3  completes needed: 1  trust model: pgp
-    gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
-    gpg: Total number processed: 1
-    gpg:               imported: 1
+You may also need more recent versions of [yubikey-personalization](https://developers.yubico.com/yubikey-personalization/Releases/) and [yubico-c](https://developers.yubico.com/yubico-c/Releases/).
 
-    $ gpg yk*sig
-    gpg: assuming signed data in 'ykpers-1.19.0.tar.gz'
-    gpg: Signature made Tue Apr 24 01:29:05 2018 PDT
-    gpg:                using RSA key 0xBCA00FD4B2168C0A
-    gpg: Good signature from "Klas Lindfors <klas@yubico.com>" [unknown]
-    gpg: WARNING: This key is not certified with a trusted signature!
-    gpg:          There is no indication that the signature belongs to the owner.
-    Primary key fingerprint: 0A3B 0262 BCA1 7053 07D5  FF06 BCA0 0FD4 B216 8C0A
+**macOS** Download and install [Homebrew](https://brew.sh/) and the following Brew packages - `gnupg yubikey-personalization hopenpgp-tools ykman pinentry-mac`
 
-    $ curl -LfsOv https://developers.yubico.com/yubico-c/Releases/libyubikey-1.13.tar.gz
+**Windows** Download and install [Gpg4Win](https://www.gpg4win.org/) and [PuTTY](https://putty.org).
 
-    $ !!.sig
-    curl -LfsOv https://developers.yubico.com/yubico-c/Releases/libyubikey-1.13.tar.gz.sig
+## Entropy
 
-    $ gpg libyubi*sig
-    gpg: assuming signed data in 'libyubikey-1.13.tar.gz'
-    gpg: Signature made Thu Mar  5 03:51:51 2015 PST
-    gpg:                using RSA key 0xBCA00FD4B2168C0A
-    gpg: Good signature from "Klas Lindfors <klas@yubico.com>" [unknown]
-    gpg: WARNING: This key is not certified with a trusted signature!
-    gpg:          There is no indication that the signature belongs to the owner.
-    Primary key fingerprint: 0A3B 0262 BCA1 7053 07D5  FF06 BCA0 0FD4 B216 8C0A
+Generating keys will require a lot of randomness. To check the available bits of entropy available on Linux:
 
-    $ tar xf libyubikey-1.13.tar.gz
+```
+$ cat /proc/sys/kernel/random/entropy_avail
+849
+```
 
-    $ cd libyubikey-1.13
+A hardware random number generator like [OneRNG](http://onerng.info/onerng/) will increase the speed of entropy generation and possibly its quality. To install and configure OneRNG:
 
-    $ ./configure && make && sudo make install
+```
+$ sudo apt-get install -y rng-tools at python-gnupg openssl
 
-    $ cd ..
+$ curl -LfO https://github.com/OneRNG/onerng.github.io/raw/master/sw/onerng_3.6-1_all.deb
 
-    $ tar xf ykpers-1.19.0.tar.gz
+$ sha256sum onerng_3.6-1_all.deb
+a9ccf7b04ee317dbfc91518542301e2d60ebe205d38e80563f29aac7cd845ccb
 
-    $ cd ykpers-1.19.0
+$ sudo dpkg -i onerng_3.6-1_all.deb
 
-    $ ./configure && make && sudo make install
+$ echo "HRNGDEVICE=/dev/ttyACM0" | sudo tee /etc/default/rng-tools
 
-    $ sudo ldconfig
+$ sudo service rng-tools restart
 ```
 
-If on [Tails](https://tails.boum.org/), you also need to install `libykpers-1-1` from the testing repository. This is a temporary fix suggested on a [securedrop issue](https://github.com/freedomofpress/securedrop/issues/1035):
+If the service fails to start, kick off `atd` and try again:
 
 ```
-$ sudo apt-get install -t testing libykpers-1-1
+$ sudo atd ; sudo service rng-tools restart
 ```
 
-## 2.2 Install - macOS
-
-You will need to install [Homebrew](https://brew.sh/) and the following brew packages:
+Plug in the OneRNG and empty `/dev/random` - the light on the device should dim briefly. Verify the available entropy pool is re-seeded.
 
 ```
-$ brew install gnupg yubikey-personalization hopenpgp-tools ykman pinentry-mac
-```
+$ cat /dev/random >/dev/null
+[Control-C]
 
-## 2.3 Install - windows
-
-Download and install [Gpg4Win](https://www.gpg4win.org/). If you are interested in
-using your YubiKey for SSH authentication you should also install [PuTTY](https://putty.org).
-
-Skip to [3.3](#3.3-create-master-key)
-
-# 3. Creating keys
+$ cat /proc/sys/kernel/random/entropy_avail
+3049
+```
 
-## 3.1 Create temporary working directory for GPG
+# Creating keys
 
-Create a directory in `/tmp` which won't survive a [reboot](https://serverfault.com/questions/377348/when-does-tmp-get-cleared):
+Create a tempotary directory which won't survive a [reboot](https://serverfault.com/questions/377348/when-does-tmp-get-cleared):
 
 ```
 $ export GNUPGHOME=$(mktemp -d) ; echo $GNUPGHOME
 /tmp/tmp.aaiTTovYgo
 ```
 
-## 3.2 Create configuration
-
-Paste the following [text](https://stackoverflow.com/questions/2500436/how-does-cat-eof-work-in-bash) into a terminal window to create a [recommended](https://github.com/drduh/config/blob/master/gpg.conf) GPG configuration:
+Create a hardened configuration for GPG with the following options or by downloading my [recommended](https://github.com/drduh/config/blob/master/gpg.conf) version directly:
 
 ```
-$ cat << EOF > $GNUPGHOME/gpg.conf
-use-agent
+$ curl -Lfo $GNUPGHOME/gpg.conf https://raw.githubusercontent.com/drduh/config/master/gpg.conf
+
+$ cat $GNUPGHOME/gpg.conf
 personal-cipher-preferences AES256 AES192 AES CAST5
 personal-digest-preferences SHA512 SHA384 SHA256 SHA224
 default-preference-list SHA512 SHA384 SHA256 SHA224 AES256 AES192 AES CAST5 ZLIB BZIP2 ZIP Uncompressed
@@ -202,293 +181,303 @@ keyid-format 0xlong
 list-options show-uid-validity
 verify-options show-uid-validity
 with-fingerprint
-EOF
+require-cross-certification
+use-agent
 ```
 
-## 3.3 Create master key
+Disable networking for the remainder of the setup.
 
-> A note on security: for optimal security you should consider performing these actions on a bootable USB that you securely erase after completing the guide. Alternatively you should disable network connectivity on your computer and make sure you securely delete all secret keys and revocation certificates.
 
-> A note on key expiry: setting an expiry essentially forces you to manage your subkeys and announces to the rest of the world that you are doing so. Setting an expiry on a primary key is ineffective for protecting the key from loss - whoever has the primary key can simply extend its expiry period. Revocation certificates are [better suited](https://security.stackexchange.com/questions/14718/does-openpgp-key-expiration-add-to-security/79386#79386) for this purpose. It may be appropriate for your use case to set expiry dates on subkeys.
+# Master key
 
-Generate a new key with GPG, selecting RSA (sign only) and the appropriate key-size:
+The first key to generate is the master key. It will be used for certification only - to issue sub-keys that are used for encryption, signing and authentication. This master key should be kept offline at all times.
 
-    % gpg --full-generate-key
-    gpg (GnuPG) 2.2.1; Copyright (C) 2017 Free Software Foundation, Inc.
-    This is free software: you are free to change and redistribute it.
-    There is NO WARRANTY, to the extent permitted by law.
+You'll be prompted to enter and verify a passphrase - keep it handy as you'll need it throughout. To generate a strong passphrase which could be written down in a hidden or secure place; or memorized:
 
-    Please select what kind of key you want:
-       (1) RSA and RSA (default)
-       (2) DSA and Elgamal
-       (3) DSA (sign only)
-       (4) RSA (sign only)
-    Your selection? 4
-    RSA keys may be between 1024 and 4096 bits long.
-    What keysize do you want? (2048) 4096
-    Requested keysize is 4096 bits
-    Please specify how long the key should be valid.
-             0 = key does not expire
-          <n>  = key expires in n days
-          <n>w = key expires in n weeks
-          <n>m = key expires in n months
-          <n>y = key expires in n years
-    Key is valid for? (0) 0
-    Key does not expire at all
-    Is this correct? (y/N) y
+```
+$ gpg --gen-random -a 0 24
+ydOmByxmDe63u7gqx2XI9eDgpvJwibNH
+```
 
-    GnuPG needs to construct a user ID to identify your key.
+Generate a new key with GPG, selecting `(4) RSA (sign only)` and `4096` bit keysize - do not set the key to expire (see Note #3).
 
-    Real name: Dr Duh
-    Email address: doc@duh.to
-    Comment:
-    You selected this USER-ID:
-        "Dr Duh <doc@duh.to>"
+```
+$ gpg --full-generate-key
+
+Please select what kind of key you want:
+   (1) RSA and RSA (default)
+   (2) DSA and Elgamal
+   (3) DSA (sign only)
+   (4) RSA (sign only)
+Your selection? 4
+RSA keys may be between 1024 and 4096 bits long.
+What keysize do you want? (2048) 4096
+Requested keysize is 4096 bits
+Please specify how long the key should be valid.
+         0 = key does not expire
+      <n>  = key expires in n days
+      <n>w = key expires in n weeks
+      <n>m = key expires in n months
+      <n>y = key expires in n years
+Key is valid for? (0) 0
+Key does not expire at all
+Is this correct? (y/N) y
+
+GnuPG needs to construct a user ID to identify your key.
+
+Real name: Dr Duh
+Email address: doc@duh.to
+Comment:
+You selected this USER-ID:
+    "Dr Duh <doc@duh.to>"
+
+Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
+
+We need to generate a lot of random bytes. It is a good idea to perform
+some other action (type on the keyboard, move the mouse, utilize the
+disks) during the prime generation; this gives the random number
+generator a better chance to gain enough entropy.
+gpg: /tmp.FLZC0xcM/trustdb.gpg: trustdb created
+gpg: key 0xFF3E7D88647EBCDB marked as ultimately trusted
+gpg: directory '/tmp.FLZC0xcM/openpgp-revocs.d' created
+gpg: revocation certificate stored as '/tmp.FLZC0xcM/openpgp-revocs.d/011CE16BD45B27A55BA8776DFF3E7D88647EBCDB.rev'
+public and secret key created and signed.
+
+Note that this key cannot be used for encryption.  You may want to use
+the command "--edit-key" to generate a subkey for this purpose.
+pub   rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [SC]
+      Key fingerprint = 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
+uid                              Dr Duh <doc@duh.to>
+```
 
-    Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
+Note that as of GPG [version 2.1](https://www.gnupg.org/faq/whats-new-in-2.1.html#autorev) a revocation certificate is automatically generated.
 
-*You'll be prompted to enter and verify a passphrase. Keep the passphrase handy
-as you'll need it throughout.*
+Export the key ID as a [variable](https://stackoverflow.com/questions/1158091/defining-a-variable-with-or-without-export/1158231#1158231) for use later:
 
-    We need to generate a lot of random bytes. It is a good idea to perform
-    some other action (type on the keyboard, move the mouse, utilize the
-    disks) during the prime generation; this gives the random number
-    generator a better chance to gain enough entropy.
-    gpg: /tmp.FLZC0xcM/trustdb.gpg: trustdb created
-    gpg: key 0xFF3E7D88647EBCDB marked as ultimately trusted
-    gpg: directory '/tmp.FLZC0xcM/openpgp-revocs.d' created
-    gpg: revocation certificate stored as '/tmp.FLZC0xcM/openpgp-revocs.d/011CE16BD45B27A55BA8776DFF3E7D88647EBCDB.rev'
-    public and secret key created and signed.
+```
+$ export KEYID=0xFF3E7D88647EBCDB
+```
 
-    Note that this key cannot be used for encryption.  You may want to use
-    the command "--edit-key" to generate a subkey for this purpose.
-    pub   rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [SC]
-          Key fingerprint = 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
-    uid                              Dr Duh <doc@duh.to>
+# Sub-keys
 
+Edit the Master key to add sub-keys:
 
-Note that as of [v2.1](https://www.gnupg.org/faq/whats-new-in-2.1.html#autorev), gpg automatically generates a revocation certificate.
+```
+$ gpg --expert --edit-key $KEYID
+
+Secret key is available.
+
+sec  rsa4096/0xEA5DE91459B80592
+    created: 2017-10-09  expires: never       usage: SC  
+    trust: ultimate      validity: ultimate
+[ultimate] (1). Dr Duh <doc@duh.to>
+```
 
-### 3.4 Save Key ID
+Use 4096-bit keysize on YubiKey 4 and 2048-bit on NEO.
 
-Export the key ID as a [variable](https://stackoverflow.com/questions/1158091/defining-a-variable-with-or-without-export/1158231#1158231) for use throughout:
+Use a 1 year expiration - it can always be renewed using the previous offline Master key.
+
+## Signing
+
+Create a [signing key](https://stackoverflow.com/questions/5421107/can-rsa-be-both-used-as-encryption-and-signature/5432623#5432623) by selecting `(4) RSA (sign only)`:
 
 ```
-$ export KEYID=0xFF3E7D88647EBCDB
+gpg> addkey
+Key is protected.
+
+You need a passphrase to unlock the secret key for
+user: "Dr Duh <doc@duh.to>"
+4096-bit RSA key, ID 0xFF3E7D88647EBCDB, created 2016-05-24
+
+Please select what kind of key you want:
+   (3) DSA (sign only)
+   (4) RSA (sign only)
+   (5) Elgamal (encrypt only)
+   (6) RSA (encrypt only)
+   (7) DSA (set your own capabilities)
+   (8) RSA (set your own capabilities)
+Your selection? 4
+RSA keys may be between 1024 and 4096 bits long.
+What keysize do you want? (2048) 4096
+Requested keysize is 4096 bits
+Please specify how long the key should be valid.
+         0 = key does not expire
+      <n>  = key expires in n days
+      <n>w = key expires in n weeks
+      <n>m = key expires in n months
+      <n>y = key expires in n years
+Key is valid for? (0) 1y
+Key expires at Mon 10 Sep 2018 00:00:00 PM UTC
+Is this correct? (y/N) y
+Really create? (y/N) y
+We need to generate a lot of random bytes. It is a good idea to perform
+some other action (type on the keyboard, move the mouse, utilize the
+disks) during the prime generation; this gives the random number
+generator a better chance to gain enough entropy.
+
+sec  rsa4096/0xFF3E7D88647EBCDB
+    created: 2017-10-09  expires: never       usage: SC  
+    trust: ultimate      validity: ultimate
+ssb  rsa4096/0xBECFA3C1AE191D15
+    created: 2017-10-09  expires: 2018-10-09       usage: S   
+[ultimate] (1). Dr Duh <doc@duh.to>
+```
+
+## Encryption
+
+Next, create an [encryption key](https://www.cs.cornell.edu/courses/cs5430/2015sp/notes/rsa_sign_vs_dec.php) by selecting `(6) RSA (encrypt only)`:
+
+```
+gpg> addkey
+Please select what kind of key you want:
+   (3) DSA (sign only)
+   (4) RSA (sign only)
+   (5) Elgamal (encrypt only)
+   (6) RSA (encrypt only)
+   (7) DSA (set your own capabilities)
+   (8) RSA (set your own capabilities)
+  (10) ECC (sign only)
+  (11) ECC (set your own capabilities)
+  (12) ECC (encrypt only)
+  (13) Existing key
+Your selection? 6
+RSA keys may be between 1024 and 4096 bits long.
+What keysize do you want? (2048) 4096
+Requested keysize is 4096 bits
+Please specify how long the key should be valid.
+         0 = key does not expire
+      <n>  = key expires in n days
+      <n>w = key expires in n weeks
+      <n>m = key expires in n months
+      <n>y = key expires in n years
+Key is valid for? (0) 1y
+Key expires at Mon 10 Sep 2018 00:00:00 PM UTC
+Is this correct? (y/N) y
+Really create? (y/N) y
+We need to generate a lot of random bytes. It is a good idea to perform
+some other action (type on the keyboard, move the mouse, utilize the
+disks) during the prime generation; this gives the random number
+generator a better chance to gain enough entropy.
+
+sec  rsa4096/0xFF3E7D88647EBCDB
+    created: 2017-10-09  expires: never       usage: SC  
+    trust: ultimate      validity: ultimate
+ssb  rsa4096/0xBECFA3C1AE191D15
+    created: 2017-10-09  expires: 2018-10-09       usage: S   
+ssb  rsa4096/0x5912A795E90DD2CF
+    created: 2017-10-09  expires: 2018-10-09       usage: E   
+[ultimate] (1). Dr Duh <doc@duh.to>
 ```
 
-### 3.5 Create subkeys
-
-Note: If using a Yubikey 4, please use **4096 bit** as the size for the subkeys; if using a YubiKey Neo, please use **2048 bit** as the size for the subkeys.
-
-Edit the key to add subkeys:
-
-    $ gpg --expert --edit-key $KEYID
-
-    Secret key is available.
-
-    sec  rsa4096/0xEA5DE91459B80592
-        created: 2017-10-09  expires: never       usage: SC  
-        trust: ultimate      validity: ultimate
-    [ultimate] (1). Dr Duh <doc@duh.to>
-
-
-### 3.5a Signing key
-
-First, create a [signing key](https://stackoverflow.com/questions/5421107/can-rsa-be-both-used-as-encryption-and-signature/5432623#5432623), selecting RSA (sign only):
-
-    gpg> addkey
-    Key is protected.
-
-    You need a passphrase to unlock the secret key for
-    user: "Dr Duh <doc@duh.to>"
-    4096-bit RSA key, ID 0xFF3E7D88647EBCDB, created 2016-05-24
-
-    Please select what kind of key you want:
-       (3) DSA (sign only)
-       (4) RSA (sign only)
-       (5) Elgamal (encrypt only)
-       (6) RSA (encrypt only)
-       (7) DSA (set your own capabilities)
-       (8) RSA (set your own capabilities)
-    Your selection? 4
-    RSA keys may be between 1024 and 4096 bits long.
-    What keysize do you want? (2048) 4096
-    Requested keysize is 4096 bits
-    Please specify how long the key should be valid.
-             0 = key does not expire
-          <n>  = key expires in n days
-          <n>w = key expires in n weeks
-          <n>m = key expires in n months
-          <n>y = key expires in n years
-    Key is valid for? (0) 0
-    Key does not expire at all
-    Is this correct? (y/N) y
-    Really create? (y/N) y
-    We need to generate a lot of random bytes. It is a good idea to perform
-    some other action (type on the keyboard, move the mouse, utilize the
-    disks) during the prime generation; this gives the random number
-    generator a better chance to gain enough entropy.
-
-    sec  rsa4096/0xFF3E7D88647EBCDB
-        created: 2017-10-09  expires: never       usage: SC  
-        trust: ultimate      validity: ultimate
-    ssb  rsa4096/0xBECFA3C1AE191D15
-        created: 2017-10-09  expires: never       usage: S   
-    [ultimate] (1). Dr Duh <doc@duh.to>
-
-### 3.5b Encryption key
-
-Next, create an [encryption key](https://www.cs.cornell.edu/courses/cs5430/2015sp/notes/rsa_sign_vs_dec.php), selecting RSA (encrypt only):
-
-    gpg> addkey
-    Please select what kind of key you want:
-       (3) DSA (sign only)
-       (4) RSA (sign only)
-       (5) Elgamal (encrypt only)
-       (6) RSA (encrypt only)
-       (7) DSA (set your own capabilities)
-       (8) RSA (set your own capabilities)
-      (10) ECC (sign only)
-      (11) ECC (set your own capabilities)
-      (12) ECC (encrypt only)
-      (13) Existing key
-    Your selection? 6
-    RSA keys may be between 1024 and 4096 bits long.
-    What keysize do you want? (2048) 4096
-    Requested keysize is 4096 bits
-    Please specify how long the key should be valid.
-             0 = key does not expire
-          <n>  = key expires in n days
-          <n>w = key expires in n weeks
-          <n>m = key expires in n months
-          <n>y = key expires in n years
-    Key is valid for? (0) 0
-    Key does not expire at all
-    Is this correct? (y/N) y
-    Really create? (y/N) y
-    We need to generate a lot of random bytes. It is a good idea to perform
-    some other action (type on the keyboard, move the mouse, utilize the
-    disks) during the prime generation; this gives the random number
-    generator a better chance to gain enough entropy.
-
-    sec  rsa4096/0xFF3E7D88647EBCDB
-        created: 2017-10-09  expires: never       usage: SC  
-        trust: ultimate      validity: ultimate
-    ssb  rsa4096/0xBECFA3C1AE191D15
-        created: 2017-10-09  expires: never       usage: S   
-    ssb  rsa4096/0x5912A795E90DD2CF
-        created: 2017-10-09  expires: never       usage: E   
-    [ultimate] (1). Dr Duh <doc@duh.to>
-
-### 3.5c Authentication key
+## Authentication
 
 Finally, create an [authentication key](https://superuser.com/questions/390265/what-is-a-gpg-with-authenticate-capability-used-for).
 
-GPG doesn't provide a 'RSA (authenticate only)' key type out of the box, so select 'RSA (set your own capabilities)' and toggle the required capabilities to end up with an Authenticate-only key:
-
-    gpg> addkey
-    Please select what kind of key you want:
-       (3) DSA (sign only)
-       (4) RSA (sign only)
-       (5) Elgamal (encrypt only)
-       (6) RSA (encrypt only)
-       (7) DSA (set your own capabilities)
-       (8) RSA (set your own capabilities)
-      (10) ECC (sign only)
-      (11) ECC (set your own capabilities)
-      (12) ECC (encrypt only)
-      (13) Existing key
-    Your selection? 8
-
-    Possible actions for a RSA key: Sign Encrypt Authenticate
-    Current allowed actions: Sign Encrypt
-
-       (S) Toggle the sign capability
-       (E) Toggle the encrypt capability
-       (A) Toggle the authenticate capability
-       (Q) Finished
-
-    Your selection? S
-
-    Possible actions for a RSA key: Sign Encrypt Authenticate
-    Current allowed actions: Encrypt
-
-       (S) Toggle the sign capability
-       (E) Toggle the encrypt capability
-       (A) Toggle the authenticate capability
-       (Q) Finished
-
-    Your selection? E
-
-    Possible actions for a RSA key: Sign Encrypt Authenticate
-    Current allowed actions:
-
-       (S) Toggle the sign capability
-       (E) Toggle the encrypt capability
-       (A) Toggle the authenticate capability
-       (Q) Finished
-
-    Your selection? A
-
-    Possible actions for a RSA key: Sign Encrypt Authenticate
-    Current allowed actions: Authenticate
-
-       (S) Toggle the sign capability
-       (E) Toggle the encrypt capability
-       (A) Toggle the authenticate capability
-       (Q) Finished
-
-    Your selection? q
-    RSA keys may be between 1024 and 4096 bits long.
-    What keysize do you want? (2048) 4096
-    Requested keysize is 4096 bits
-    Please specify how long the key should be valid.
-             0 = key does not expire
-          <n>  = key expires in n days
-          <n>w = key expires in n weeks
-          <n>m = key expires in n months
-          <n>y = key expires in n years
-    Key is valid for? (0) 0
-    Key does not expire at all
-    Is this correct? (y/N) y
-    Really create? (y/N) y
-    We need to generate a lot of random bytes. It is a good idea to perform
-    some other action (type on the keyboard, move the mouse, utilize the
-    disks) during the prime generation; this gives the random number
-    generator a better chance to gain enough entropy.
-
-
-    sec  rsa4096/0xFF3E7D88647EBCDB
-        created: 2017-10-09  expires: never       usage: SC  
-        trust: ultimate      validity: ultimate
-    ssb  rsa4096/0xBECFA3C1AE191D15
-        created: 2017-10-09  expires: never       usage: S   
-    ssb  rsa4096/0x5912A795E90DD2CF
-        created: 2017-10-09  expires: never       usage: E   
-    ssb  rsa4096/0x3F29127E79649A3D
-        created: 2017-10-09  expires: never       usage: A   
-    [ultimate] (1). Dr Duh <doc@duh.to>
-
-    gpg> save
-
-## 3.6 Check your work
-
-List your new secret keys:
-
-    $ gpg --list-secret-keys
-    /tmp.FLZC0xcM/pubring.kbx
-    -------------------------------------------------------------------------
-    sec   rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [SC]
-          Key fingerprint = 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
-    uid                            Dr Duh <doc@duh.to>
-    ssb   rsa4096/0xBECFA3C1AE191D15 2017-10-09 [S]
-    ssb   rsa4096/0x5912A795E90DD2CF 2017-10-09 [E]
-    ssb   rsa4096/0x3F29127E79649A3D 2017-10-09 [A]
-
-Verify with OpenPGP key checks:
-
-If you're on Linux or macOS, use the automated [key best practice checker](https://riseup.net/en/security/message-security/openpgp/best-practices#openpgp-key-checks):
+GPG doesn't provide an authenticate-only key type, so select `(8) RSA (set your own capabilities)` and toggle the required capabilities until the only allowed action is `Authenticate`:
+
+```
+gpg> addkey
+Please select what kind of key you want:
+   (3) DSA (sign only)
+   (4) RSA (sign only)
+   (5) Elgamal (encrypt only)
+   (6) RSA (encrypt only)
+   (7) DSA (set your own capabilities)
+   (8) RSA (set your own capabilities)
+  (10) ECC (sign only)
+  (11) ECC (set your own capabilities)
+  (12) ECC (encrypt only)
+  (13) Existing key
+Your selection? 8
+
+Possible actions for a RSA key: Sign Encrypt Authenticate
+Current allowed actions: Sign Encrypt
+
+   (S) Toggle the sign capability
+   (E) Toggle the encrypt capability
+   (A) Toggle the authenticate capability
+   (Q) Finished
+
+Your selection? S
+
+Possible actions for a RSA key: Sign Encrypt Authenticate
+Current allowed actions: Encrypt
+
+   (S) Toggle the sign capability
+   (E) Toggle the encrypt capability
+   (A) Toggle the authenticate capability
+   (Q) Finished
+
+Your selection? E
+
+Possible actions for a RSA key: Sign Encrypt Authenticate
+Current allowed actions:
+
+   (S) Toggle the sign capability
+   (E) Toggle the encrypt capability
+   (A) Toggle the authenticate capability
+   (Q) Finished
+
+Your selection? A
+
+Possible actions for a RSA key: Sign Encrypt Authenticate
+Current allowed actions: Authenticate
+
+   (S) Toggle the sign capability
+   (E) Toggle the encrypt capability
+   (A) Toggle the authenticate capability
+   (Q) Finished
+
+Your selection? q
+RSA keys may be between 1024 and 4096 bits long.
+What keysize do you want? (2048) 4096
+Requested keysize is 4096 bits
+Please specify how long the key should be valid.
+         0 = key does not expire
+      <n>  = key expires in n days
+      <n>w = key expires in n weeks
+      <n>m = key expires in n months
+      <n>y = key expires in n years
+Key is valid for? (0) 1y
+Key expires at Mon 10 Sep 2018 00:00:00 PM UTC
+Is this correct? (y/N) y
+Really create? (y/N) y
+We need to generate a lot of random bytes. It is a good idea to perform
+some other action (type on the keyboard, move the mouse, utilize the
+disks) during the prime generation; this gives the random number
+generator a better chance to gain enough entropy.
+
+sec  rsa4096/0xFF3E7D88647EBCDB
+    created: 2017-10-09  expires: never       usage: SC  
+    trust: ultimate      validity: ultimate
+ssb  rsa4096/0xBECFA3C1AE191D15
+    created: 2017-10-09  expires: 2018-10-09       usage: S   
+ssb  rsa4096/0x5912A795E90DD2CF
+    created: 2017-10-09  expires: 2018-10-09       usage: E   
+ssb  rsa4096/0x3F29127E79649A3D
+    created: 2017-10-09  expires: 2018-10-09       usage: A   
+[ultimate] (1). Dr Duh <doc@duh.to>
+
+gpg> save
+```
+
+# Verify keys
+
+List the generated secret keys and verify the output:
+
+```
+$ gpg --list-secret-keys
+/tmp.FLZC0xcM/pubring.kbx
+-------------------------------------------------------------------------
+sec   rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [SC]
+      Key fingerprint = 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
+uid                            Dr Duh <doc@duh.to>
+ssb   rsa4096/0xBECFA3C1AE191D15 2017-10-09 [S] [expires: 2018-10-09]
+ssb   rsa4096/0x5912A795E90DD2CF 2017-10-09 [E] [expires: 2018-10-09]
+ssb   rsa4096/0x3F29127E79649A3D 2017-10-09 [A] [expires: 2018-10-09]
+```    
+
+To verify with OpenPGP key checks, use the automated [key best practice checker](https://riseup.net/en/security/message-security/openpgp/best-practices#openpgp-key-checks):
 
 ```
 $ sudo apt-get install hopenpgp-tools
@@ -497,708 +486,733 @@ $ gpg --export $KEYID | hokey lint
 
 The output will display any problems with your key in red text. If everything is green, your key passes each of the tests. If it is red, your key has failed one of the tests.
 
->hokey may warn (orange text) about cross certification for the authentication key. GPG's [Signing Subkey Cross-Certification](https://gnupg.org/faq/subkey-cross-certify.html) documentation has more detail on cross certification, and gpg v2.2.1 notes "subkey <keyid> does not sign and so does not need to be cross-certified".
+> hokey may warn (orange text) about cross certification for the authentication key. GPG's [Signing Subkey Cross-Certification](https://gnupg.org/faq/subkey-cross-certify.html) documentation has more detail on cross certification, and gpg v2.2.1 notes "subkey <keyid> does not sign and so does not need to be cross-certified".
 
-## 3.7 Export keys
+# Export keys
 
-### 3.7a Linux/macOS
+The Master and sub-keys will be encrypted with your passphrase when exported.
 
 Save a copy of your keys:
 
 ```
 $ gpg --armor --export-secret-keys $KEYID > $GNUPGHOME/mastersub.key
+
 $ gpg --armor --export-secret-subkeys $KEYID > $GNUPGHOME/sub.key
 ```
 
-The exported (primary) key will still have the passphrase in place.
-
-In addition to the backup below, you might want to keep a separate copy of the
-revocation certificate in a safe place - `$GNUPGHOME/openpgp-revocs.d/<key fingerprint>.rev`
-
-### 3.7b Windows
+On Windows, note that using any extension other than `.gpg` or attempting IO redirection to a file will garble the secret key, making it impossible to import it again at a later date:
 
 ```
 $ gpg --armor --export-secret-keys $KEYID -o \path\to\dir\mastersub.gpg
+
 $ gpg --armor --export-secret-subkeys $KEYID -o \path\to\dir\sub.gpg
 ```
 
-Please note that using any extension other than .gpg or attempting IO redirection to a file will garble your secret key, making it impossible to import it again at a later date.
+# Backup keys
 
-The exported (primary) key will still have the passphrase in place.
-
-In addition to the back up detailed in the next step, you should note the location of your revocation certificate from the terminal output and copy it to a secure location. Careful, anyone that has this certificate can revoke your key!
-
-## 3.8 Backup everything
-
-### 3.8a Linux/macOS
-
-Once keys are moved to hardware, they cannot be extracted again, so make sure you have made an **encrypted** backup before proceeding.
+Once keys are moved to hardware, they cannot be extracted again, so make sure you have made an **encrypted** backup before proceeding. An encrypted USB drive or container can be made using [VeraCrypt](https://www.veracrypt.fr/en/Downloads.html).
 
 Also consider using a [paper copy](http://www.jabberwocky.com/software/paperkey/) of the keys as an additional backup measure.
 
-You can also use the pre-compiled executables available at [veracrypt.fr](https://www.veracrypt.fr/en/Downloads.html)
-
 To format and encrypt a USB drive on Linux, first attach it and check its label:
 
-    $ dmesg | tail
-    [ 7667.607011] scsi8 : usb-storage 2-1:1.0
-    [ 7667.608766] usbcore: registered new interface driver usb-storage
-    [ 7668.874016] scsi 8:0:0:0: USB 0: 0 ANSI: 6
-    [ 7668.874242] sd 8:0:0:0: Attached scsi generic sg4 type 0
-    [ 7668.874682] sd 8:0:0:0: [sde] 62980096 512-byte logical blocks: (32.2 GB/30.0 GiB)
-    [ 7668.875022] sd 8:0:0:0: [sde] Write Protect is off
-    [ 7668.875023] sd 8:0:0:0: [sde] Mode Sense: 43 00 00 00
-    [ 7668.877939]  sde: sde1
-    [ 7668.879514] sd 8:0:0:0: [sde] Attached SCSI removable disk
+```
+$ sudo dmesg | tail
+scsi8 : usb-storage 2-1:1.0
+usbcore: registered new interface driver usb-storage
+scsi 8:0:0:0: USB 0: 0 ANSI: 6
+sd 8:0:0:0: Attached scsi generic sg4 type 0
+sd 8:0:0:0: [sde] 62980096 512-byte logical blocks: (32.2 GB/30.0 GiB)
+sd 8:0:0:0: [sde] Write Protect is off
+sd 8:0:0:0: [sde] Mode Sense: 43 00 00 00
+ sde: sde1
+sd 8:0:0:0: [sde] Attached SCSI removable disk
+```
 
 Check the size to make sure it's the right drive:
 
-    $ sudo fdisk -l | grep /dev/sde
-    Disk /dev/sde: 30 GiB, 32245809152 bytes, 62980096 sectors
-    /dev/sde1        2048 62980095 62978048  30G  6 FAT16
+```
+$ sudo fdisk -l /dev/sde
+Disk /dev/sde: 30 GiB, 32245809152 bytes, 62980096 sectors
+/dev/sde1        2048 62980095 62978048  30G  6 FAT16
+```
 
 Erase and create a new partition table:
 
-    $ sudo fdisk /dev/sde
+```
+$ sudo fdisk /dev/sde
 
-    Welcome to fdisk (util-linux 2.25.2).
-    Changes will remain in memory only, until you decide to write them.
-    Be careful before using the write command.
+Welcome to fdisk (util-linux 2.25.2).
+Changes will remain in memory only, until you decide to write them.
+Be careful before using the write command.
 
-    Command (m for help): o
-    Created a new DOS disklabel with disk identifier 0xeac7ee35.
+Command (m for help): o
+Created a new DOS disklabel with disk identifier 0xeac7ee35.
 
-    Command (m for help): w
-    The partition table has been altered.
-    Calling ioctl() to re-read partition table.
-    Syncing disks.
+Command (m for help): w
+The partition table has been altered.
+Calling ioctl() to re-read partition table.
+Syncing disks.
+```
 
 Remove and reinsert the USB drive, then create a new partition, selecting defaults:
 
-    $ sudo fdisk /dev/sde
-
-    Welcome to fdisk (util-linux 2.25.2).
-    Changes will remain in memory only, until you decide to write them.
-    Be careful before using the write command.
-
-    Command (m for help): n
-    Partition type
-       p   primary (0 primary, 0 extended, 4 free)
-       e   extended (container for logical partitions)
-    Select (default p): p
-    Partition number (1-4, default 1): 1
-    First sector (2048-62980095, default 2048):
-    Last sector, +sectors or +size{K,M,G,T,P} (2048-62980095, default 62980095):
-
-    Created a new partition 1 of type 'Linux' and of size 30 GiB.
-    Command (m for help): w
-    The partition table has been altered.
-    Calling ioctl() to re-read partition table.
-    Syncing disks.
+```
+$ sudo fdisk /dev/sde
+
+Welcome to fdisk (util-linux 2.25.2).
+Changes will remain in memory only, until you decide to write them.
+Be careful before using the write command.
+
+Command (m for help): n
+Partition type
+   p   primary (0 primary, 0 extended, 4 free)
+   e   extended (container for logical partitions)
+Select (default p): p
+Partition number (1-4, default 1): 1
+First sector (2048-62980095, default 2048):
+Last sector, +sectors or +size{K,M,G,T,P} (2048-62980095, default 62980095):
+
+Created a new partition 1 of type 'Linux' and of size 30 GiB.
+
+Command (m for help): w
+The partition table has been altered.
+Calling ioctl() to re-read partition table.
+Syncing disks.
+```
 
 Use [LUKS](https://askubuntu.com/questions/97196/how-secure-is-an-encrypted-luks-filesystem) to encrypt the new partition:
 
-    $ sudo cryptsetup luksFormat /dev/sde1
+```
+$ sudo cryptsetup luksFormat /dev/sde1
 
-    WARNING!
-    ========
-    This will overwrite data on /dev/sde1 irrevocably.
+WARNING!
+========
+This will overwrite data on /dev/sde1 irrevocably.
 
-    Are you sure? (Type uppercase yes): YES
-    Enter passphrase:
-    Verify passphrase:
+Are you sure? (Type uppercase yes): YES
+Enter passphrase:
+Verify passphrase:
+```
 
 Mount the partition:
 
-    $ sudo cryptsetup luksOpen /dev/sde1 encrypted-usb
-    Enter passphrase for /dev/sde1:
+```
+$ sudo cryptsetup luksOpen /dev/sde1 usb
+Enter passphrase for /dev/sde1:
+```
 
 Create a filesystem:
 
-    $ sudo mkfs.ext4 /dev/mapper/encrypted-usb -L encrypted-usb
-    mke2fs 1.42.12 (29-Aug-2014)
-    Creating filesystem with 7871744 4k blocks and 1970416 inodes
-    Superblock backups stored on blocks:
-            32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
-            4096000
-
-    Allocating group tables: done
-    Writing inode tables: done
-    Creating journal (32768 blocks): done
-    Writing superblocks and filesystem accounting information: done
+```
+$ sudo mkfs.ext4 /dev/mapper/usb -L usb
+mke2fs 1.43.4 (31-Jan-2017)
+Creating filesystem with 7871744 4k blocks and 1970416 inodes
+Superblock backups stored on blocks:
+        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
+        4096000
+
+Allocating group tables: done
+Writing inode tables: done
+Creating journal (32768 blocks): done
+Writing superblocks and filesystem accounting information: done
+```
 
 Mount the filesystem:
 
-    $ sudo mkdir /mnt/usb
-    $ sudo mount /dev/mapper/encrypted-usb /mnt/usb
-
-Copy files to it:
-
-    $ sudo cp -avi $GNUPGHOME /mnt/usb
-    ‘/tmp/tmp.aaiTTovYgo’ -> ‘/mnt/usb/tmp.aaiTTovYgo’
-    ‘/tmp/tmp.aaiTTovYgo/revoke.txt’ -> ‘/mnt/usb/tmp.aaiTTovYgo/revoke.txt’
-    ‘/tmp/tmp.aaiTTovYgo/gpg.conf’ -> ‘/mnt/usb/tmp.aaiTTovYgo/gpg.conf’
-    ‘/tmp/tmp.aaiTTovYgo/trustdb.gpg’ -> ‘/mnt/usb/tmp.aaiTTovYgo/trustdb.gpg’
-    ‘/tmp/tmp.aaiTTovYgo/random_seed’ -> ‘/mnt/usb/tmp.aaiTTovYgo/random_seed’
-    ‘/tmp/tmp.aaiTTovYgo/master.key’ -> ‘/mnt/usb/tmp.aaiTTovYgo/master.key’
-    ‘/tmp/tmp.aaiTTovYgo/secring.gpg’ -> ‘/mnt/usb/tmp.aaiTTovYgo/secring.gpg’
-    ‘/tmp/tmp.aaiTTovYgo/mastersub.key’ -> ‘/mnt/usb/tmp.aaiTTovYgo/mastersub.key’
-    ‘/tmp/tmp.aaiTTovYgo/sub.key’ -> ‘/mnt/usb/tmp.aaiTTovYgo/sub.key’
-    ‘/tmp/tmp.aaiTTovYgo/pubring.gpg~’ -> ‘/mnt/usb/tmp.aaiTTovYgo/pubring.gpg~’
-    ‘/tmp/tmp.aaiTTovYgo/pubring.gpg’ -> ‘/mnt/usb/tmp.aaiTTovYgo/pubring.gpg’
-
-Keep the backup mounted if you plan on setting up two or more keys (as `keytocard` will [delete](https://lists.gnupg.org/pipermail/gnupg-users/2016-July/056353.html) the local copy on save).
-
-Otherwise unmount and disconnected the encrypted USB drive:
-
-    $ sudo umount /mnt/usb
-    $ sudo cryptsetup luksClose encrypted-usb
-
-### 3.8b Windows
+```
+$ sudo mount /dev/mapper/usb /mnt
+```
 
-An encrypted flash drive or container can be made using [VeraCrypt](https://www.veracrypt.fr/en/Downloads.html).
+Backup all GPG files to it:
 
-## 3.9 Configure YubiKey
+```
+$ sudo cp -avi $GNUPGHOME /mnt
+[...]
+‘/tmp/tmp.aaiTTovYgo/revoke.txt’ -> ‘/mnt/tmp.aaiTTovYgo/revoke.txt’
+‘/tmp/tmp.aaiTTovYgo/gpg.conf’ -> ‘/mnt/tmp.aaiTTovYgo/gpg.conf’
+‘/tmp/tmp.aaiTTovYgo/master.key’ -> ‘/mnt/tmp.aaiTTovYgo/master.key’
+‘/tmp/tmp.aaiTTovYgo/secring.gpg’ -> ‘/mnt/tmp.aaiTTovYgo/secring.gpg’
+‘/tmp/tmp.aaiTTovYgo/mastersub.key’ -> ‘/mnt/tmp.aaiTTovYgo/mastersub.key’
+‘/tmp/tmp.aaiTTovYgo/sub.key’ -> ‘/mnt/tmp.aaiTTovYgo/sub.key’
+‘/tmp/tmp.aaiTTovYgo/pubring.gpg’ -> ‘/mnt/tmp.aaiTTovYgo/pubring.gpg’
+[...]
+```
 
-### 3.9a Linux/macOS
+Keep the backup mounted if you plan on setting up two or more keys as `keytocard` will [delete](https://lists.gnupg.org/pipermail/gnupg-users/2016-July/056353.html) the local copy on save.
 
-YubiKey NEOs shipped after November 2015 have [all modes enabled](https://www.yubico.com/support/knowledge-base/categories/articles/yubikey-neo-manager/), skip to the next step.
+Otherwise, unmount and disconnected the encrypted USB drive:
 
-Older versions of the YubiKey NEO may need to be reconfigured as a composite USB device (HID + CCID) which allows OTPs to be emitted while in use as a smart card.
+```
+$ sudo umount /mnt
 
-Plug in your YubiKey and configure it:
+$ sudo cryptsetup luksClose usb
+```
 
-    $ ykpersonalize -m82
-    Firmware version 4.2.7 Touch level 527 Program sequence 4
+# Configure YubiKey
 
-    The USB mode will be set to: 0x82
+Plug in YubiKey and configure it with the `ykpersonalize` utility:
 
-    Commit? (y/n) [n]: y
+```
+$ sudo ykpersonalize -m82
+Firmware version 4.3.7 Touch level 527 Program sequence 1
 
-> The -m option is the mode command. To see the different modes, enter `ykpersonalize –help`. Mode 82 (in hex) enables the YubiKey NEO as a composite USB device (HID + CCID).  Once you have changed the mode, you need to re-boot the YubiKey – so remove and re-insert it.
+The USB mode will be set to: 0x82
 
-> On YubiKey NEO with firmware version 3.3 or higher you can enable composite USB device with -m86 instead of -m82.
+Commit? (y/n) [n]: y
+```
 
-https://www.yubico.com/2012/12/yubikey-neo-openpgp/
-https://www.yubico.com/2012/12/yubikey-neo-composite-device/
+The -m option is the mode command. To see the different modes, enter `ykpersonalize –help`. Mode 82 (in hex) enables the YubiKey NEO as a composite USB device (HID + CCID).  Once you have changed the mode, you need to re-boot the YubiKey – so remove and re-insert it. On YubiKey NEO with firmware version 3.3 or higher, you can enable composite USB device with `-m86` instead of `-m82`.
 
-### 3.9b Windows
+**Note** YubiKey NEO shipped after November 2015 have [all modes enabled](https://www.yubico.com/support/knowledge-base/categories/articles/yubikey-neo-manager/); so this configuration may be skipped. Older versions of the YubiKey NEO may need to be reconfigured as a composite USB device (HID + CCID) which allows OTPs to be emitted while in use as a SmartCard.
 
-Use the [YubiKey NEO Manager](https://www.yubico.com/products/services-software/download/yubikey-neo-manager/) to enable CCID functionality.
+**Windows** Use the [YubiKey NEO Manager](https://www.yubico.com/products/services-software/download/yubikey-neo-manager/) to enable CCID functionality.
 
-## 3.10 Configure smartcard
+# Configure Smartcard
 
 Use GPG to configure YubiKey as a smartcard:
 
-    $ gpg --card-edit
-    Reader ...........: Yubico Yubikey 4 OTP U2F CCID
-    Application ID ...: D2760001240102010006055532110000
-    Version ..........: 2.1
-    Manufacturer .....: Yubico
-    Serial number ....: 05553211
-    Name of cardholder: [not set]
-    Language prefs ...: [not set]
-    Sex ..............: unspecified
-    URL of public key : [not set]
-    Login data .......: [not set]
-    Signature PIN ....: not forced
-    Key attributes ...: rsa4096 rsa4096 rsa4096
-    Max. PIN lengths .: 127 127 127
-    PIN retry counter : 3 3 3
-    Signature counter : 0
-    Signature key ....: [none]
-    Encryption key....: [none]
-    Authentication key: [none]
-    General key info..: [none]
-
-### 3.10a Change PINs
-
-The default PIN codes are `12345678` for the Admin PIN (aka PUK) and `123456` for the PIN. The CCID-mode PINs can be up to 127 ASCII characters long.
-
-The Admin PIN is required for some card operations, and to unblock a PIN that has been entered incorrectly more than three times. See the GnuPG documentation on [Managing PINs](https://www.gnupg.org/howtos/card-howto/en/ch03s02.html) for details.
-
-    gpg/card> admin
-    Admin commands are allowed
+```
+$ gpg --edit-card
+Reader ...........: Yubico Yubikey 4 OTP U2F CCID
+Application ID ...: D2760001240102010006055532110000
+Version ..........: 2.1
+Manufacturer .....: Yubico
+Serial number ....: 05553211
+Name of cardholder: [not set]
+Language prefs ...: [not set]
+Sex ..............: unspecified
+URL of public key : [not set]
+Login data .......: [not set]
+Signature PIN ....: not forced
+Key attributes ...: rsa2048 rsa2048 rsa2048
+Max. PIN lengths .: 127 127 127
+PIN retry counter : 3 0 3
+Signature counter : 0
+Signature key ....: [none]
+Encryption key....: [none]
+Authentication key: [none]
+General key info..: [none]
+```
 
-    gpg/card> passwd
-    gpg: OpenPGP card no. D2760001240102010006055532110000 detected
+## Change PIN
 
-    1 - change PIN
-    2 - unblock PIN
-    3 - change Admin PIN
-    4 - set the Reset Code
-    Q - quit
+The default PIN codes are `12345678` for the Admin PIN (aka PUK) and `123456` for the PIN. The CCID-mode PINs can be up to 127 ASCII characters long.
 
-    Your selection? 3
-    PIN changed.
+The Admin PIN is required for some card operations and to unblock a PIN that has been entered incorrectly more than three times. See the GnuPG documentation on [Managing PINs](https://www.gnupg.org/howtos/card-howto/en/ch03s02.html) for details.
 
-    1 - change PIN
-    2 - unblock PIN
-    3 - change Admin PIN
-    4 - set the Reset Code
-    Q - quit
+```
+gpg/card> admin
+Admin commands are allowed
 
-    Your selection? 1
-    PIN changed.
+gpg/card> passwd
+gpg: OpenPGP card no. D2760001240102010006055532110000 detected
 
-    1 - change PIN
-    2 - unblock PIN
-    3 - change Admin PIN
-    4 - set the Reset Code
-    Q - quit
+1 - change PIN
+2 - unblock PIN
+3 - change Admin PIN
+4 - set the Reset Code
+Q - quit
 
-    Your selection? q
+Your selection? 3
+PIN changed.
 
-### 3.10b Set card information
+1 - change PIN
+2 - unblock PIN
+3 - change Admin PIN
+4 - set the Reset Code
+Q - quit
 
-Some fields are optional:
+Your selection? 1
+PIN changed.
 
-    gpg/card> name
-    Cardholder's surname: Duh
-    Cardholder's given name: Dr
+1 - change PIN
+2 - unblock PIN
+3 - change Admin PIN
+4 - set the Reset Code
+Q - quit
 
-    gpg/card> lang
-    Language preferences: en
+Your selection? q
+```
 
-    gpg/card> login
-    Login data (account name): doc@duh.to
+## Set information
 
-    gpg/card> (Press Enter)
+Some fields are optional.
 
-    Application ID ...: D2760001240102010006055532110000
-    Version ..........: 2.1
-    Manufacturer .....: unknown
-    Serial number ....: 05553211
-    Name of cardholder: Dr Duh
-    Language prefs ...: en
-    Sex ..............: unspecified
-    URL of public key : [not set]
-    Login data .......: doc@duh.to
-    Private DO 4 .....: [not set]
-    Signature PIN ....: not forced
-    Key attributes ...: 2048R 2048R 2048R
-    Max. PIN lengths .: 127 127 127
-    PIN retry counter : 3 3 3
-    Signature counter : 0
-    Signature key ....: [none]
-    Encryption key....: [none]
-    Authentication key: [none]
-    General key info..: [none]
+```
+gpg/card> name
+Cardholder's surname: Duh
+Cardholder's given name: Dr
+
+gpg/card> lang
+Language preferences: en
+
+gpg/card> login
+Login data (account name): doc@duh.to
+
+gpg/card> [Press Enter]
+
+Application ID ...: D2760001240102010006055532110000
+Version ..........: 2.1
+Manufacturer .....: unknown
+Serial number ....: 05553211
+Name of cardholder: Dr Duh
+Language prefs ...: en
+Sex ..............: unspecified
+URL of public key : [not set]
+Login data .......: doc@duh.to
+Private DO 4 .....: [not set]
+Signature PIN ....: not forced
+Key attributes ...: 2048R 2048R 2048R
+Max. PIN lengths .: 127 127 127
+PIN retry counter : 3 0 3
+Signature counter : 0
+Signature key ....: [none]
+Encryption key....: [none]
+Authentication key: [none]
+General key info..: [none]
+
+gpg/card> quit
+```
 
-    gpg/card> quit
+# Transfer keys
 
-## 3.11 Transfer keys
+Transferring keys to YubiKey using `keytocard` is a one-way operation only, so make sure you've made a backup before proceeding.
 
-Transferring keys to YubiKey hardware using `keytocard` is a one-way operation only, so make sure you've made a backup before proceeding.
+Previous GPG versions required the `toggle` command before selecting keys. The currently selected key(s) are indicated with an `*`. When moving keys only one key should be selected at a time.
 
-Previous gpg versions required the `toggle` command before selecting keys. The currently selected key(s) are indicated with an `*`. When moving keys only one key should be selected at a time.
+```
+$ gpg --edit-key $KEYID
+
+Secret key is available.
+
+sec  rsa4096/0xFF3E7D88647EBCDB
+    created: 2017-10-09  expires: never       usage: SC  
+    trust: ultimate      validity: ultimate
+ssb  rsa4096/0xBECFA3C1AE191D15
+    created: 2017-10-09  expires: 2018-10-09  usage: S   
+ssb  rsa4096/0x5912A795E90DD2CF
+    created: 2017-10-09  expires: 2018-10-09  usage: E   
+ssb  rsa4096/0x3F29127E79649A3D
+    created: 2017-10-09  expires: 2018-10-09  usage: A   
+[ultimate] (1). Dr Duh <doc@duh.to>
+```
 
-    % gpg --edit-key $KEYID
+## Signing
 
-    Secret key is available.
+Select and move the signature key. You will be prompted for the key passphrase and admin PIN).
 
-    sec  rsa4096/0xFF3E7D88647EBCDB
-        created: 2017-10-09  expires: never       usage: SC  
-        trust: ultimate      validity: ultimate
-    ssb  rsa4096/0xBECFA3C1AE191D15
-        created: 2017-10-09  expires: never       usage: S   
-    ssb  rsa4096/0x5912A795E90DD2CF
-        created: 2017-10-09  expires: never       usage: E   
-    ssb  rsa4096/0x3F29127E79649A3D
-        created: 2017-10-09  expires: never       usage: A   
-    [ultimate] (1). Dr Duh <doc@duh.to>
+```
+gpg> key 1
+
+sec  rsa4096/0xFF3E7D88647EBCDB
+    created: 2017-10-09  expires: never       usage: SC
+    trust: ultimate      validity: ultimate
+ssb* rsa4096/0xBECFA3C1AE191D15
+    created: 2017-10-09  expires: 2018-10-09  usage: S
+ssb  rsa4096/0x5912A795E90DD2CF
+    created: 2017-10-09  expires: 2018-10-09  usage: E
+ssb  rsa4096/0x3F29127E79649A3D
+    created: 2017-10-09  expires: 2018-10-09  usage: A
+[ultimate] (1). Dr Duh <doc@duh.to>
+
+gpg> keytocard
+Please select where to store the key:
+   (1) Signature key
+   (3) Authentication key
+Your selection? 1
+
+You need a passphrase to unlock the secret key for
+user: "Dr Duh <doc@duh.to>"
+4096-bit RSA key, ID 0xBECFA3C1AE191D15, created 2016-05-24
+```
 
-### 3.11a Signature key
+## Encryption
 
-Select and move the signature key (you will be prompted for the key passphrase and admin PIN):
+Type `key 1` again to de-select and `key 2` to select the next key:
 
-    gpg> key 1
+```
+gpg> key 1
+
+gpg> key 2
+
+sec  rsa4096/0xFF3E7D88647EBCDB
+    created: 2017-10-09  expires: never       usage: SC
+    trust: ultimate      validity: ultimate
+ssb  rsa4096/0xBECFA3C1AE191D15
+    created: 2017-10-09  expires: 2018-10-09  usage: S
+ssb* rsa4096/0x5912A795E90DD2CF
+    created: 2017-10-09  expires: 2018-10-09  usage: E
+ssb  rsa4096/0x3F29127E79649A3D
+    created: 2017-10-09  expires: 2018-10-09  usage: A
+[ultimate] (1). Dr Duh <doc@duh.to>
+
+gpg> keytocard
+Please select where to store the key:
+   (2) Encryption key
+Your selection? 2
+
+[...]
+```
 
-    sec  rsa4096/0xFF3E7D88647EBCDB
-        created: 2017-10-09  expires: never       usage: SC
-        trust: ultimate      validity: ultimate
-    ssb* rsa4096/0xBECFA3C1AE191D15
-        created: 2017-10-09  expires: never       usage: S
-    ssb  rsa4096/0x5912A795E90DD2CF
-        created: 2017-10-09  expires: never       usage: E
-    ssb  rsa4096/0x3F29127E79649A3D
-        created: 2017-10-09  expires: never       usage: A
-    [ultimate] (1). Dr Duh <doc@duh.to>
+## Authentication
 
-    gpg> keytocard
-    Please select where to store the key:
-       (1) Signature key
-       (3) Authentication key
-    Your selection? 1
+Type `key 2` again to deselect and `key 3` to select the last key:
 
-    You need a passphrase to unlock the secret key for
-    user: "Dr Duh <doc@duh.to>"
-    4096-bit RSA key, ID 0xBECFA3C1AE191D15, created 2016-05-24
+```
+gpg> key 2
+
+gpg> key 3
+
+sec  rsa4096/0xFF3E7D88647EBCDB
+    created: 2017-10-09  expires: never       usage: SC
+    trust: ultimate      validity: ultimate
+ssb  rsa4096/0xBECFA3C1AE191D15
+    created: 2017-10-09  expires: 2018-10-09  usage: S
+ssb  rsa4096/0x5912A795E90DD2CF
+    created: 2017-10-09  expires: 2018-10-09  usage: E
+ssb* rsa4096/0x3F29127E79649A3D
+    created: 2017-10-09  expires: 2018-10-09  usage: A
+[ultimate] (1). Dr Duh <doc@duh.to>
+
+gpg> keytocard
+Please select where to store the key:
+   (3) Authentication key
+Your selection? 3
+
+gpg> save
+```
 
-### 3.11b Encryption key
+# Verify card
 
-Type `key 1` again to deselect and `key 2` to select the next key:
+Verify the sub-keys have moved to YubiKey as indicated by `ssb>`:
 
-    gpg> key 1
+```
+$ gpg --list-secret-keys
+/tmp.FLZC0xcM/pubring.kbx
+-------------------------------------------------------------------------
+sec   rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [SC]
+      Key fingerprint = 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
+uid                            Dr Duh <doc@duh.to>
+ssb>  rsa4096/0xBECFA3C1AE191D15 2017-10-09 [S] [expires: 2018-10-09]
+ssb>  rsa4096/0x5912A795E90DD2CF 2017-10-09 [E] [expires: 2018-10-09]
+ssb>  rsa4096/0x3F29127E79649A3D 2017-10-09 [A] [expires: 2018-10-09]
+```
 
-    gpg> key 2
+# Export public key
 
-    sec  rsa4096/0xFF3E7D88647EBCDB
-        created: 2017-10-09  expires: never       usage: SC
-        trust: ultimate      validity: ultimate
-    ssb  rsa4096/0xBECFA3C1AE191D15
-        created: 2017-10-09  expires: never       usage: S
-    ssb* rsa4096/0x5912A795E90DD2CF
-        created: 2017-10-09  expires: never       usage: E
-    ssb  rsa4096/0x3F29127E79649A3D
-        created: 2017-10-09  expires: never       usage: A
-    [ultimate] (1). Dr Duh <doc@duh.to>
+Mount another USB drive to copy the public key, or save it somewhere where you can easily access later.
 
-    gpg> keytocard
-    Please select where to store the key:
-       (2) Encryption key
-    Your selection? 2
-    ...
+```
+$ gpg --armor --export $KEYID > /mnt/public-usb-key/pubkey.txt
+```
 
-### 3.11c Authentication key
+On Windows:
 
-Type `key 2` again to deselect and `key 3` to select the next key:
+```
+$ gpg --armor --export $KEYID -o \path\to\dir\pubkey.gpg
+```
 
-    gpg> key 2
+Optionally, the public key may be uploaded to a [public keyserver](https://debian-administration.org/article/451/Submitting_your_GPG_key_to_a_keyserver):
 
-    gpg> key 3
+```
+$ gpg --send-key $KEYID
+gpg: sending key 0xFF3E7D88647EBCDB to hkps server hkps.pool.sks-keyservers.net
+[...]
+```
 
-    sec  rsa4096/0xFF3E7D88647EBCDB
-        created: 2017-10-09  expires: never       usage: SC
-        trust: ultimate      validity: ultimate
-    ssb  rsa4096/0xBECFA3C1AE191D15
-        created: 2017-10-09  expires: never       usage: S
-    ssb  rsa4096/0x5912A795E90DD2CF
-        created: 2017-10-09  expires: never       usage: E
-    ssb* rsa4096/0x3F29127E79649A3D
-        created: 2017-10-09  expires: never       usage: A
-    [ultimate] (1). Dr Duh <doc@duh.to>
+After some time, the public key will to propagate to [other](https://pgp.key-server.io/pks/lookup?search=doc%40duh.to&fingerprint=on&op=vindex) [servers](https://pgp.mit.edu/pks/lookup?search=doc%40duh.to&op=index).
 
-    gpg> keytocard
-    Please select where to store the key:
-       (3) Authentication key
-    Your selection? 3
+# Cleanup
 
-Save and quit:
+Ensure you have:
 
-    gpg> save
+* Saved the password to the Master key.
+* Saved a copy of the Master key, subkeys and revocation certificates on encrypted offline storage.
+* Saved the password to that encrypted volume in a separate location.
+* Saved a copy of the public key somewhere easily accessible later.
+* Moved the Encryption, Signing and Authentication subkeys to YubiKey.
 
-## 3.12 Check your work
+Then reboot or [securely delete](http://srm.sourceforge.net/) `$GNUPGHOME` and remove the secret keys from the GPG keyring:
 
-`ssb>` indicates a stub to the private key on smartcard:
+```
+$ sudo srm -r $GNUPGHOME || sudo rm -rf $GNUPGHOME
 
-    % gpg --list-secret-keys
-    /tmp.FLZC0xcM/pubring.kbx
-    -------------------------------------------------------------------------
-    sec   rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [SC]
-          Key fingerprint = 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
-    uid                            Dr Duh <doc@duh.to>
-    ssb>  rsa4096/0xBECFA3C1AE191D15 2017-10-09 [S]
-    ssb>  rsa4096/0x5912A795E90DD2CF 2017-10-09 [E]
-    ssb>  rsa4096/0x3F29127E79649A3D 2017-10-09 [A]
+$ gpg --delete-secret-key $KEYID
+```
 
+Make sure you have securely erased keys, including recovation certificates, if a Live image was not used!
 
-## 3.13 Export public key
+# Using keys
 
-This file should be publicly shared:
+You can reboot back into the Live image to test YubiKey.
 
-**Linux/macOS**
+Install required programs:
 
-    $ gpg --armor --export $KEYID > /mnt/public-usb-key/pubkey.txt
+```
+$ sudo apt-get update
+$ sudo apt-get install -y \
+     curl gnupg2 gnupg-agent \
+     cryptsetup scdaemon pcscd
+```
 
-**Windows**
+Create a hardened configuration for GPG with the following options or by downloading my [recommended](https://github.com/drduh/config/blob/master/gpg.conf) version directly:
 
-	$ gpg --armor --export $KEYID -o \path\to\dir\pubkey.gpg
+```
+$ mkdir ~/.gnupg ; curl -Lfo ~/.gnupg/gpg.conf https://raw.githubusercontent.com/drduh/config/master/gpg.conf
 
+$ cat ~/.gnupg/gpg.conf
+personal-cipher-preferences AES256 AES192 AES CAST5
+personal-digest-preferences SHA512 SHA384 SHA256 SHA224
+default-preference-list SHA512 SHA384 SHA256 SHA224 AES256 AES192 AES CAST5 ZLIB BZIP2 ZIP Uncompressed
+cert-digest-algo SHA512
+s2k-digest-algo SHA512
+s2k-cipher-algo AES256
+charset utf-8
+fixed-list-mode
+no-comments
+no-emit-version
+keyid-format 0xlong
+list-options show-uid-validity
+verify-options show-uid-validity
+with-fingerprint
+require-cross-certification
+use-agent
 
-Optionally, it may be uploaded to a [public keyserver](https://debian-administration.org/article/451/Submitting_your_GPG_key_to_a_keyserver):
+$ chmod 600 ~/.gnupg/gpg.conf
+```
 
-    $ gpg --send-key $KEYID
-    gpg: sending key 0xFF3E7D88647EBCDB to hkps server hkps.pool.sks-keyservers.net
-    [...]
+# Import public key
 
-After a little while, it ought to propagate to [other](https://pgp.key-server.io/pks/lookup?search=doc%40duh.to&fingerprint=on&op=vindex) [servers](https://pgp.mit.edu/pks/lookup?search=doc%40duh.to&op=index).
+To import the public key from a file on an encrypted USB drive:
 
-## 3.14 Finish
+```
+$ sudo cryptsetup luksOpen /dev/sdd1 usb
+Enter passphrase for /dev/sdd1:
 
-If all went well, you should now reboot or [securely delete](http://srm.sourceforge.net/) `$GNUPGHOME`.
+$ sudo mount /dev/mapper/usb /mnt
 
-If you are using Windows, the easiest way to remove the secret keys is to purge them from your GPG keyring.
+$ gpg --import /mnt/pubkey.txt
+gpg: key 0xFF3E7D88647EBCDB: public key "Dr Duh <doc@duh.to>" imported
+gpg: Total number processed: 1
+gpg:               imported: 1
+```
 
-    $ gpg --delete-secret-key $KEYID
+To download the public key from a keyserver:
 
-Make sure you backup up your key prior to doing this as the action is irreversible. You may also want to consider securely deleting the revocation certificate from your hard drive.
+```
+$ gpg --recv 0xFF3E7D88647EBCDB
+gpg: requesting key 0xFF3E7D88647EBCDB from hkps server hkps.pool.sks-keyservers.net
+[...]
+gpg: key 0xFF3E7D88647EBCDB: public key "Dr Duh <doc@duh.to>" imported
+gpg: Total number processed: 1
+gpg:               imported: 1
+```
 
-# 4. Using keys
+If you get the error `gpgkeys: HTTP fetch error 1: unsupported protocol` - this means you need to install a special version of curl which supports GPG:
 
-## 4.1 Create GPG configuration
+```
+$ sudo apt-get install -y gnupg-curl
+```
 
-**Skip this section if you are on Windows**
+## Trust master key
 
-Paste the following text into a terminal window to create a [recommended](https://github.com/drduh/config/blob/master/gpg.conf) GPG configuration:
+Edit the Master key to assign it ultimate trust by selecting `trust` then option `5`:
 
-    $ cat << EOF > ~/.gnupg/gpg.conf
-    auto-key-locate keyserver
-    keyserver hkps://hkps.pool.sks-keyservers.net
-    keyserver-options no-honor-keyserver-url
-    keyserver-options no-honor-keyserver-url
-    personal-cipher-preferences AES256 AES192 AES CAST5
-    personal-digest-preferences SHA512 SHA384 SHA256 SHA224
-    default-preference-list SHA512 SHA384 SHA256 SHA224 AES256 AES192 AES CAST5 ZLIB BZIP2 ZIP Uncompressed
-    cert-digest-algo SHA512
-    s2k-cipher-algo AES256
-    s2k-digest-algo SHA512
-    charset utf-8
-    fixed-list-mode
-    no-comments
-    no-emit-version
-    keyid-format 0xlong
-    list-options show-uid-validity
-    verify-options show-uid-validity
-    with-fingerprint
-    use-agent
-    require-cross-certification
-    EOF
+```
+$ gpg --edit-key 0xFF3E7D88647EBCDB
+
+Secret key is available.
+
+gpg> trust
+pub  4096R/0xFF3E7D88647EBCDB  created: 2016-05-24  expires: never       usage: SC
+                               trust: unknown       validity: unknown
+sub  4096R/0xBECFA3C1AE191D15  created: 2017-10-09  expires: 2018-10-09  usage: S
+sub  4096R/0x5912A795E90DD2CF  created: 2017-10-09  expires: 2018-10-09  usage: E
+sub  4096R/0x3F29127E79649A3D  created: 2017-10-09  expires: 2018-10-09  usage: A
+[ unknown] (1). Dr Duh <doc@duh.to>
+
+Please decide how far you trust this user to correctly verify other users' keys
+(by looking at passports, checking fingerprints from different sources, etc.)
+
+  1 = I don't know or won't say
+  2 = I do NOT trust
+  3 = I trust marginally
+  4 = I trust fully
+  5 = I trust ultimately
+  m = back to the main menu
+
+Your decision? 5
+Do you really want to set this key to ultimate trust? (y/N) y
+
+pub  4096R/0xFF3E7D88647EBCDB  created: 2016-05-24  expires: never       usage: SC
+                               trust: ultimate      validity: unknown
+sub  4096R/0xBECFA3C1AE191D15  created: 2017-10-09  expires: 2018-10-09  usage: S
+sub  4096R/0x5912A795E90DD2CF  created: 2017-10-09  expires: 2018-10-09  usage: E
+sub  4096R/0x3F29127E79649A3D  created: 2017-10-09  expires: 2018-10-09  usage: A
+[ unknown] (1). Dr Duh <doc@duh.to>
+Please note that the shown key validity is not necessarily correct
+unless you restart the program.
+
+gpg> save
+```
 
-Ensure you change to correct rights of that file to at least avoid a warning message about incorrect file rights
+# Insert YubiKey
 
-    chmod 600 ~/.gnupg/gpg.conf
+Re-connect Yubikey and check the status:
 
-## 4.2 Import public key
+```
+$ gpg --card-status
+Application ID ...: D2760001240102010006055532110000
+Version ..........: 2.1
+Manufacturer .....: Yubico
+Serial number ....: 05553211
+Name of cardholder: Dr Duh
+Language prefs ...: en
+Sex ..............: unspecified
+URL of public key : [not set]
+Login data .......: doc@duh.to
+Signature PIN ....: not forced
+Key attributes ...: 4096R 4096R 4096R
+Max. PIN lengths .: 127 127 127
+PIN retry counter : 3 3 3
+Signature counter : 0
+Signature key ....: 07AA 7735 E502 C5EB E09E  B8B0 BECF A3C1 AE19 1D15
+      created ....: 2016-05-24 23:22:01
+Encryption key....: 6F26 6F46 845B BEB8 BDF3  7E9B 5912 A795 E90D D2CF
+      created ....: 2016-05-24 23:29:03
+Authentication key: 82BE 7837 6A3F 2E7B E556  5E35 3F29 127E 7964 9A3D
+      created ....: 2016-05-24 23:36:40
+General key info..: pub  4096R/0xBECFA3C1AE191D15 2016-05-24 Dr Duh <doc@duh.to>
+sec#  4096R/0xFF3E7D88647EBCDB  created: 2016-05-24  expires: never
+ssb>  4096R/0xBECFA3C1AE191D15  created: 2017-10-09  expires: 2018-10-09
+                      card-no: 0006 05553211
+ssb>  4096R/0x5912A795E90DD2CF  created: 2017-10-09  expires: 2018-10-09
+                      card-no: 0006 05553211
+ssb>  4096R/0x3F29127E79649A3D  created: 2017-10-09  expires: 2018-10-09
+                      card-no: 0006 05553211
+```
 
-Import it from a file:
+`sec#` indicates master key is not available (as it should be stored encrypted offline).
 
-    $ gpg --import < /mnt/public-usb-key/pubkey.txt
-    gpg: key 0xFF3E7D88647EBCDB: public key "Dr Duh <doc@duh.to>" imported
-    gpg: Total number processed: 1
-    gpg:               imported: 1  (RSA: 1)
+**Note** If you see `General key info..: [none]` in the output instead - go back and import the public key using the previous step.
 
-Or download from a keyserver:
+# Encryption
 
-    $ gpg --recv 0xFF3E7D88647EBCDB
-    gpg: requesting key 0xFF3E7D88647EBCDB from hkps server hkps.pool.sks-keyservers.net
-    [...]
-    gpg: key 0xFF3E7D88647EBCDB: public key "Dr Duh <doc@duh.to>" imported
-    gpg: Total number processed: 1
-    gpg:               imported: 1  (RSA: 1)
+```
+$ echo "test message string" | gpg --encrypt --armor --recipient 0xFF3E7D88647EBCDB
+-----BEGIN PGP MESSAGE-----
+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+=pzkv
+-----END PGP MESSAGE-----
+```
 
-**Linux/macOS:** You may get an error `gpgkeys: HTTP fetch error 1: unsupported protocol` -- this means you need to install a special version of curl which supports gnupg:
+# Decryption
 
-$ sudo apt-get install gnupg-curl
+```
+$ gpg --decrypt --armor
+-----BEGIN PGP MESSAGE-----
+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+=pzkv
+-----END PGP MESSAGE-----
+gpg: encrypted with 4096-bit RSA key, ID 0x5912A795E90DD2CF, created
+2016-05-24
+      "Dr Duh <doc@duh.to>"
+
+[Press Control-D]
+
+test message string
+```
 
-## 4.3 Insert YubiKey
+# Signing
 
-Unplug and replug the Yubikey. Check the card's status:
+```
+$ echo "test message string" | gpg --armor --clearsign --default-key 0xBECFA3C1AE191D15
+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA512
+
+test message string
+-----BEGIN PGP SIGNATURE-----
+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+=+ylJ
+-----END PGP SIGNATURE-----
+```
 
-    $ gpg --card-status
-    Application ID ...: D2760001240102010006055532110000
-    Version ..........: 2.1
-    Manufacturer .....: Yubico
-    Serial number ....: 05553211
-    Name of cardholder: Dr Duh
-    Language prefs ...: en
-    Sex ..............: unspecified
-    URL of public key : [not set]
-    Login data .......: doc@duh.to
-    Signature PIN ....: not forced
-    Key attributes ...: 4096R 4096R 4096R
-    Max. PIN lengths .: 127 127 127
-    PIN retry counter : 3 3 3
-    Signature counter : 0
-    Signature key ....: 07AA 7735 E502 C5EB E09E  B8B0 BECF A3C1 AE19 1D15
-          created ....: 2016-05-24 23:22:01
-    Encryption key....: 6F26 6F46 845B BEB8 BDF3  7E9B 5912 A795 E90D D2CF
-          created ....: 2016-05-24 23:29:03
-    Authentication key: 82BE 7837 6A3F 2E7B E556  5E35 3F29 127E 7964 9A3D
-          created ....: 2016-05-24 23:36:40
-    General key info..: pub  4096R/0xBECFA3C1AE191D15 2016-05-24 Dr Duh <doc@duh.to>
-    sec#  4096R/0xFF3E7D88647EBCDB  created: 2016-05-24  expires: never
-    ssb>  4096R/0xBECFA3C1AE191D15  created: 2016-05-24  expires: never
-                          card-no: 0006 05553211
-    ssb>  4096R/0x5912A795E90DD2CF  created: 2016-05-24  expires: never
-                          card-no: 0006 05553211
-    ssb>  4096R/0x3F29127E79649A3D  created: 2016-05-24  expires: never
-                          card-no: 0006 05553211
+# Verifying signature
 
-`sec#` indicates master key is not available (as it should be stored encrypted offline).
+```
+$ gpg
+gpg: Go ahead and type your message ...
+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA512
+
+test message string
+-----BEGIN PGP SIGNATURE-----
+
+iQIcBAEBCgAGBQJXRPo8AAoJEL7Po8GuGR0Vh8wP/jYXTR8SAZIZSMVCOyAjH37f
++3RGxA3Zr085cVFoixI8rxYOSu0Vs2cAzAbJHNcOcD7vXxTHcX4T8kfKoF9A4U1u
+XTJ42eEjpO0fX76tFX2/Uzxl43ES0dO7Y82ho7xcnaYwakVUEcWfUpfDAroLKZOs
+wCZGr8Z64QDQzxQ9L45Zc61wMx9JEIWD4BnagllfeOYrEwTJfYG8uhDDNYx0jjJp
+j1PBHn5d556aX6DHUH05kq3wszvQ4W40RctLgAA3l1VnEKebhBKjLZA/EePAvQV4
+QM7MFUV1X/pi2zlyoZSnHkVl8b5Q7RU5ZtRpq9fdkDDepeiUo5PNBUMJER1gn4bm
+ri8DtavkwTNWBRLnVR2gHBmVQNN7ZDOkHcfyqR4I9chx6TMpfcxk0zATAHh8Donp
+FVPKySifuXpunn+0MwdZl5XkhHGdpdYQz4/LAZUGhrA9JTnFtc4cl4JrTzufF8Sr
+c3JJumMsyGvw9OQKQHF8gHme4PBu/4P31LpfX9wzPOTpJaI31Sg5kdJLTo9M9Ppo
+uvkmJS7ETjLQZOsRyAEn7gcEKZQGPQcNAgfEgQPoepS/KvvI68u+JMJm4n24k2kQ
+fEkp501u8kAZkWauhiL+
+=+ylJ
+-----END PGP SIGNATURE-----
+
+[Press Control-D]
+
+gpg: Signature made Wed 25 May 2016 00:00:00 AM UTC
+gpg:                using RSA key 0xBECFA3C1AE191D15
+gpg: Good signature from "Dr Duh <doc@duh.to>" [ultimate]
+Primary key fingerprint: 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
+     Subkey fingerprint: 07AA 7735 E502 C5EB E09E  B8B0 BECF A3C1 AE19 1D15
+```
 
-**Note** If you see `General key info..: [none]` in the output instead, first import your public key using the previous step.
-
-## 4.4 GnuPG
-
-### 4.4a Trust master key
-
-Edit the imported key to assign it ultimate trust:
-
-    $ gpg --edit-key 0xFF3E7D88647EBCDB
-
-    Secret key is available.
-
-    pub  4096R/0xFF3E7D88647EBCDB  created: 2016-05-24  expires: never       usage: SC
-                                   trust: unknown       validity: unknown
-    sub  4096R/0xBECFA3C1AE191D15  created: 2016-05-24  expires: never       usage: S
-    sub  4096R/0x5912A795E90DD2CF  created: 2016-05-24  expires: never       usage: E
-    sub  4096R/0x3F29127E79649A3D  created: 2016-05-24  expires: never       usage: A
-    [ unknown] (1). Dr Duh <doc@duh.to>
-
-    gpg> trust
-    pub  4096R/0xFF3E7D88647EBCDB  created: 2016-05-24  expires: never       usage: SC
-                                   trust: unknown       validity: unknown
-    sub  4096R/0xBECFA3C1AE191D15  created: 2016-05-24  expires: never       usage: S
-    sub  4096R/0x5912A795E90DD2CF  created: 2016-05-24  expires: never       usage: E
-    sub  4096R/0x3F29127E79649A3D  created: 2016-05-24  expires: never       usage: A
-    [ unknown] (1). Dr Duh <doc@duh.to>
-
-    Please decide how far you trust this user to correctly verify other users' keys
-    (by looking at passports, checking fingerprints from different sources, etc.)
-
-      1 = I don't know or won't say
-      2 = I do NOT trust
-      3 = I trust marginally
-      4 = I trust fully
-      5 = I trust ultimately
-      m = back to the main menu
-
-    Your decision? 5
-    Do you really want to set this key to ultimate trust? (y/N) y
-
-    pub  4096R/0xFF3E7D88647EBCDB  created: 2016-05-24  expires: never       usage: SC
-                                   trust: ultimate      validity: unknown
-    sub  4096R/0xBECFA3C1AE191D15  created: 2016-05-24  expires: never       usage: S
-    sub  4096R/0x5912A795E90DD2CF  created: 2016-05-24  expires: never       usage: E
-    sub  4096R/0x3F29127E79649A3D  created: 2016-05-24  expires: never       usage: A
-    [ unknown] (1). Dr Duh <doc@duh.to>
-    Please note that the shown key validity is not necessarily correct
-    unless you restart the program.
-
-    gpg> quit
-
-### 4.4b Encryption
-
-Encrypt some sample text:
-
-**Note for Windows users:**
-Replace `echo "$(uname -a)"` with `echo "Test123"`
-
-    $ echo "$(uname -a)" | gpg --encrypt --armor --recipient 0xFF3E7D88647EBCDB
-    -----BEGIN PGP MESSAGE-----
-
-    hQIMA1kSp5XpDdLPAQ/+JyYfLaUS/+llEzQaKDb5mWhG4HlUgD99dNJUXakm085h
-    PSSt3I8Ac0ctwyMnenZvBEbHMqdRnfZJsj5pHidKcAZrhgs+he+B1tdZ/KPa8inx
-    NIGqd8W1OraVSFmPEdC1kQ5he6R/WCDH1NNel9+fvLtQDCBQaFae/s3yXCSSQU6q
-    HKCJLyHK8K9hDvgFmXOY8j1qTknBvDbmYdcCKVE1ejgpUCi3WatusobpWozsp0+b
-    6DN8bXyfxLPYm1PTLfW7v4kwddktB8eVioV8A45lndJZvliSqDwxhrwyE5VGsArS
-    NmqzBkCaOHQFr0ofL91xgwpCI5kM2ukIR5SxUO4hvzlHn58QVL9GfAyCHMFtJs3o
-    Q9eiR0joo9TjTwR8XomVhRJShrrcPeGgu3YmIak4u7OndyBFpu2E79RQ0ehpl2gY
-    tSECB6mNd/gt0Wy3y15ccaFI4CVP6jrMN6q3YhXqNC7GgI/OWkVZIAgUFYnbmIQe
-    tQ3z3wlbvFFngeFy5IlhsPduK8T9XgPnOtgQxHaepKz0h3m2lJegmp4YZ4CbS9h6
-    kcBTUjys5Vin1SLuqL4PhErzmlAZgVzG2PANsnHYPe2hwN4NlFtOND1wgBCtBFBs
-    1pqz1I0O+jmyId+jVlAK076c2AwdkVbokKUcIT/OcTc0nwHjOUttJGmkUHlbt/nS
-    iAFNniSfzf6fwAFHgsvWiRJMa3keolPiqoUdh0tBIiI1zxOMaiTL7C9BFdpnvzYw
-    Krj0pDc7AlF4spWhm58WgAW20P8PGcVQcN6mSTG8jKbXVSP3bvgPXkpGAOLKMV/i
-    pLORcRPbauusBqovgaBWU/i3pMYrbhZ+LQbVEaJlvblWu6xe8HhS/jo=
-    =pzkv
-    -----END PGP MESSAGE-----
-
-### 4.4c Decryption
-
-Decrypt the sample text by pasting it:
-
-    $ gpg --decrypt --armor
-    -----BEGIN PGP MESSAGE-----
-
-    hQIMA1kSp5XpDdLPAQ/+JyYfLaUS/+llEzQaKDb5mWhG4HlUgD99dNJUXakm085h
-    PSSt3I8Ac0ctwyMnenZvBEbHMqdRnfZJsj5pHidKcAZrhgs+he+B1tdZ/KPa8inx
-    NIGqd8W1OraVSFmPEdC1kQ5he6R/WCDH1NNel9+fvLtQDCBQaFae/s3yXCSSQU6q
-    HKCJLyHK8K9hDvgFmXOY8j1qTknBvDbmYdcCKVE1ejgpUCi3WatusobpWozsp0+b
-    6DN8bXyfxLPYm1PTLfW7v4kwddktB8eVioV8A45lndJZvliSqDwxhrwyE5VGsArS
-    NmqzBkCaOHQFr0ofL91xgwpCI5kM2ukIR5SxUO4hvzlHn58QVL9GfAyCHMFtJs3o
-    Q9eiR0joo9TjTwR8XomVhRJShrrcPeGgu3YmIak4u7OndyBFpu2E79RQ0ehpl2gY
-    tSECB6mNd/gt0Wy3y15ccaFI4CVP6jrMN6q3YhXqNC7GgI/OWkVZIAgUFYnbmIQe
-    tQ3z3wlbvFFngeFy5IlhsPduK8T9XgPnOtgQxHaepKz0h3m2lJegmp4YZ4CbS9h6
-    kcBTUjys5Vin1SLuqL4PhErzmlAZgVzG2PANsnHYPe2hwN4NlFtOND1wgBCtBFBs
-    1pqz1I0O+jmyId+jVlAK076c2AwdkVbokKUcIT/OcTc0nwHjOUttJGmkUHlbt/nS
-    iAFNniSfzf6fwAFHgsvWiRJMa3keolPiqoUdh0tBIiI1zxOMaiTL7C9BFdpnvzYw
-    Krj0pDc7AlF4spWhm58WgAW20P8PGcVQcN6mSTG8jKbXVSP3bvgPXkpGAOLKMV/i
-    pLORcRPbauusBqovgaBWU/i3pMYrbhZ+LQbVEaJlvblWu6xe8HhS/jo=
-    =pzkv
-    -----END PGP MESSAGE-----
-    gpg: encrypted with 4096-bit RSA key, ID 0x5912A795E90DD2CF, created
-    2016-05-24
-          "Dr Duh <doc@duh.to>"
-
-    (Press Control-D)
-
-    Linux workstation 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt25-2 (2016-04-08) x86_64 GNU/Linux
-
-### 4.4d Signing
-
-Sign some sample text using the signing subkey:
-
-    $ echo "$(uname -a)" | gpg --armor --clearsign --default-key 0xBECFA3C1AE191D15
-    -----BEGIN PGP SIGNED MESSAGE-----
-    Hash: SHA512
-
-    Linux workstation 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt25-2 (2016-04-08) x86_64 GNU/Linux
-    -----BEGIN PGP SIGNATURE-----
-
-    iQIcBAEBCgAGBQJXRPo8AAoJEL7Po8GuGR0Vh8wP/jYXTR8SAZIZSMVCOyAjH37f
-    k6JxB0rF928WDYPihjo/d0Jd+XpoV1g+oipDRjP78xqR9H/CJZlE10IPQbNaomFs
-    +3RGxA3Zr085cVFoixI8rxYOSu0Vs2cAzAbJHNcOcD7vXxTHcX4T8kfKoF9A4U1u
-    XTJ42eEjpO0fX76tFX2/Uzxl43ES0dO7Y82ho7xcnaYwakVUEcWfUpfDAroLKZOs
-    wCZGr8Z64QDQzxQ9L45Zc61wMx9JEIWD4BnagllfeOYrEwTJfYG8uhDDNYx0jjJp
-    j1PBHn5d556aX6DHUH05kq3wszvQ4W40RctLgAA3l1VnEKebhBKjLZA/EePAvQV4
-    QM7MFUV1X/pi2zlyoZSnHkVl8b5Q7RU5ZtRpq9fdkDDepeiUo5PNBUMJER1gn4bm
-    ri8DtavkwTNWBRLnVR2gHBmVQNN7ZDOkHcfyqR4I9chx6TMpfcxk0zATAHh8Donp
-    FVPKySifuXpunn+0MwdZl5XkhHGdpdYQz4/LAZUGhrA9JTnFtc4cl4JrTzufF8Sr
-    c3JJumMsyGvw9OQKQHF8gHme4PBu/4P31LpfX9wzPOTpJaI31Sg5kdJLTo9M9Ppo
-    uvkmJS7ETjLQZOsRyAEn7gcEKZQGPQcNAgfEgQPoepS/KvvI68u+JMJm4n24k2kQ
-    fEkp501u8kAZkWauhiL+
-    =+ylJ
-    -----END PGP SIGNATURE-----
-
-### 4.4e Verifying signature
-
-Verify the previous signature:
-
-    $ gpg
-    gpg: Go ahead and type your message ...
-    -----BEGIN PGP SIGNED MESSAGE-----
-    Hash: SHA512
-
-    Linux workstation 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt25-2 (2016-04-08) x86_64 GNU/Linux
-    -----BEGIN PGP SIGNATURE-----
-
-    iQIcBAEBCgAGBQJXRPo8AAoJEL7Po8GuGR0Vh8wP/jYXTR8SAZIZSMVCOyAjH37f
-    +3RGxA3Zr085cVFoixI8rxYOSu0Vs2cAzAbJHNcOcD7vXxTHcX4T8kfKoF9A4U1u
-    XTJ42eEjpO0fX76tFX2/Uzxl43ES0dO7Y82ho7xcnaYwakVUEcWfUpfDAroLKZOs
-    wCZGr8Z64QDQzxQ9L45Zc61wMx9JEIWD4BnagllfeOYrEwTJfYG8uhDDNYx0jjJp
-    j1PBHn5d556aX6DHUH05kq3wszvQ4W40RctLgAA3l1VnEKebhBKjLZA/EePAvQV4
-    QM7MFUV1X/pi2zlyoZSnHkVl8b5Q7RU5ZtRpq9fdkDDepeiUo5PNBUMJER1gn4bm
-    ri8DtavkwTNWBRLnVR2gHBmVQNN7ZDOkHcfyqR4I9chx6TMpfcxk0zATAHh8Donp
-    FVPKySifuXpunn+0MwdZl5XkhHGdpdYQz4/LAZUGhrA9JTnFtc4cl4JrTzufF8Sr
-    c3JJumMsyGvw9OQKQHF8gHme4PBu/4P31LpfX9wzPOTpJaI31Sg5kdJLTo9M9Ppo
-    uvkmJS7ETjLQZOsRyAEn7gcEKZQGPQcNAgfEgQPoepS/KvvI68u+JMJm4n24k2kQ
-    fEkp501u8kAZkWauhiL+
-    =+ylJ
-    -----END PGP SIGNATURE-----
-
-    (Press Control-D)
-
-    gpg: Signature made Wed 25 May 2016 00:00:00 AM UTC
-    gpg:                using RSA key 0xBECFA3C1AE191D15
-    gpg: Good signature from "Dr Duh <doc@duh.to>" [ultimate]
-    Primary key fingerprint: 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
-         Subkey fingerprint: 07AA 7735 E502 C5EB E09E  B8B0 BECF A3C1 AE19 1D15
-
-## 4.5 SSH - Linux/macOS
-
-### 4.5a A Note on GPG Agent's SSH Agent
+# SSH
 
 [gpg-agent](https://wiki.archlinux.org/index.php/GnuPG#SSH_agent) supports the OpenSSH ssh-agent protocol (`enable-ssh-support`), as well as Putty's Pageant on Windows (`enable-putty-support`). This means it can be used instead of the traditional ssh-agent / pageant. There are some differences from ssh-agent, notably that gpg-agent does not _cache_ keys rather it converts, encrypts and stores them - persistently - as GPG keys and then makes them available to ssh clients. Any existing ssh private keys that you'd like to keep in `gpg-agent` should be deleted after they've been imported to the GPG agent.
 
@@ -1206,144 +1220,153 @@ When importing the key to `gpg-agent`, you'll be prompted for a passphrase to pr
 
 Probably the biggest thing missing from `gpg-agent`'s ssh agent support is being able to remove keys. `ssh-add -d/-D` have no effect. Instead, you need to use the `gpg-connect-agent` utility to lookup a key's keygrip, match that with the desired ssh key fingerprint (as an MD5) and then delete that keygrip. The [gnupg-users mailing list](https://lists.gnupg.org/pipermail/gnupg-users/2016-August/056499.html) has more information.
 
-### 4.5b Update configuration
+## Create configuration
+
+Create a hardened configuration for gpg-agent with the following options or by downloading my [recommended](https://github.com/drduh/config/blob/master/gpg-agent.conf) version directly:
 
-Paste the following text into a terminal window to create a [recommended](https://github.com/drduh/config/blob/master/gpg-agent.conf) GPG agent configuration:
+```
+$ curl -Lfo ~/.gnupg/gpg-agent.conf https://raw.githubusercontent.com/drduh/config/master/gpg-agent.conf
 
-    $ cat << EOF > ~/.gnupg/gpg-agent.conf
-    enable-ssh-support
-    pinentry-program /usr/bin/pinentry-curses
-    default-cache-ttl 60
-    max-cache-ttl 120
-    EOF
+$ cat ~/.gnupg/gpg-agent.conf
+enable-ssh-support
+pinentry-program /usr/bin/pinentry-curses
+default-cache-ttl 60
+max-cache-ttl 120
+```
 
-If you are using Linux on the desktop, you may want to use `/usr/bin/pinentry-gnome3` to use a GUI manager. For macOS, try `brew install pinentry-mac`, and adjust the `pinentry-program` setting to suit.
+Alternatively, you may want to use `/usr/bin/pinentry-gnome3` to use a GUI manager. On macOS, use `brew install pinentry-mac` and adjust the program path to suit.
 
-### 4.5c Replace ssh-agent with gpg-agent
+## Replace agents
 
-To launch `gpg-agent` for use by ssh use the `gpg-connect-agent /bye` or `gpgconf --launch gpg-agent` commands.
+To launch `gpg-agent` for use by SSH, use the `gpg-connect-agent /bye` or `gpgconf --launch gpg-agent` commands.
 
-Depending on how your environment is set up, you might need to add these to your shell `rc` file:
+Add these to your shell `rc` file:
 
-    export GPG_TTY="$(tty)"
-    export SSH_AUTH_SOCK=$(gpgconf --list-dirs agent-ssh-socket)
-    gpgconf --launch gpg-agent
+```
+export GPG_TTY="$(tty)"
+export SSH_AUTH_SOCK=$(gpgconf --list-dirs agent-ssh-socket)
+gpgconf --launch gpg-agent
+```
 
-**Note** On some systems, for example Arch Linux-based distributions, you may need to replace the second and the third line with:
+On some systems, you may need to use the following instead:
 
 ```
+export GPG_TTY="$(tty)"
 export SSH_AUTH_SOCK="/run/user/$UID/gnupg/S.gpg-agent.ssh"
 gpg-connect-agent updatestartuptty /bye
 ```
 
-### 4.5d Copy public key to server
+## Copy public key
 
-There is a `-L` option of `ssh-add` that lists public key parameters of all identities currently represented by the agent.  Copy and paste the following output to the server authorized_keys file:
+Copy and paste the output from `ssh-add` to the server's `authorized_keys` file:
 
 ```
 $ ssh-add -L
 ssh-rsa AAAAB4NzaC1yc2EAAAADAQABAAACAz[...]zreOKM+HwpkHzcy9DQcVG2Nw== cardno:000605553211
 ```
 
-#### (Optional) Save public key for identity file configuration
+## (Optional) Save public key for identity file configuration
 
-By default `ssh` attempts to use all the identities available via the ssh agent. It's often a good idea to manage exactly which key(s) `ssh` will use to connect to a server, for example to separate different roles or [to avoid being fingerprinted by untrusted ssh servers](https://blog.filippo.io/ssh-whoami-filippo-io/). To do this you'll need to use the `ssh` command line argument `-l [identity_file]` or the `IdentityFile` and `IdentitiesOnly` options in `.ssh/config`.
+By default, SSH attempts to use all the identities available via the agent. It's often a good idea to manage exactly which keys SSH will use to connect to a server, for example to separate different roles or [to avoid being fingerprinted by untrusted ssh servers](https://blog.filippo.io/ssh-whoami-filippo-io/). To do this you'll need to use the command line argument `-l [identity_file]` or the `IdentityFile` and `IdentitiesOnly` options in `.ssh/config`.
 
 The argument provided to `IdentityFile` is traditionally the path to the _private_ key file (for example `IdentityFile ~/.ssh/id_rsa`). For the Yubikey - indeed, in general for keys stored in an ssh agent - `IdentityFile` should point to the _public_ key file, `ssh` will select the appropriate private key from those available via the ssh agent. To prevent `ssh` from trying all keys in the agent use the `IdentitiesOnly yes` option along with one or more `-i` or `IdentityFile` options for the target host.
 
 To reiterate, with `IdentitiesOnly yes`, `ssh` will not automatically enumerate public keys loaded into `ssh-agent` or `gpg-agent`. This means `publickey` authentication will not proceed unless explicitly named by `ssh -i [identity_file]` or in `.ssh/config` on a per-host basis.
 
-In the case of Yubikey usage, to extract the public key from the ssh agent:
+In the case of YubiKey usage, to extract the public key from the ssh agent:
 
-    $ ssh-add -L | grep "cardno:000605553211" > ~/.ssh/id_rsa_yubikey.pub
+```
+$ ssh-add -L | grep "cardno:000605553211" > ~/.ssh/id_rsa_yubikey.pub
+```
 
 Then you can explicitly associate this Yubikey-stored key for used with a host, `github.com` for example, as follows:
 
-    $ cat << EOF >> ~/.ssh/config
-    Host github.com
-        IdentitiesOnly yes
-        IdentityFile ~/.ssh/id_rsa_yubikey.pub
-    EOF
-
-
-### 4.5e Connect with public key authentication
-
-    $ ssh git@github.com -vvv
-    [...]
-    debug2: key: cardno:000605553211 (0x1234567890),
-    debug1: Authentications that can continue: publickey
-    debug3: start over, passed a different list publickey
-    debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
-    debug3: authmethod_lookup publickey
-    debug3: remaining preferred: keyboard-interactive,password
-    debug3: authmethod_is_enabled publickey
-    debug1: Next authentication method: publickey
-    debug1: Offering RSA public key: cardno:000605553211
-    debug3: send_pubkey_test
-    debug2: we sent a publickey packet, wait for reply
-    debug1: Server accepts key: pkalg ssh-rsa blen 535
-    debug2: input_userauth_pk_ok: fp e5:de:a5:74:b1:3e:96:9b:85:46:e7:28:53:b4:82:c3
-    debug3: sign_and_send_pubkey: RSA e5:de:a5:74:b1:3e:96:9b:85:46:e7:28:53:b4:82:c3
-    debug1: Authentication succeeded (publickey).
-    [...]
-
-
-**Note** To make multiple connections or securely transfer many files, consider using the [ControlMaster](https://en.wikibooks.org/wiki/OpenSSH/Cookbook/Multiplexing) ssh option. Also see [drduh/config/ssh_config](https://github.com/drduh/config/blob/master/ssh_config).
+```
+$ cat << EOF >> ~/.ssh/config
+Host github.com
+    IdentitiesOnly yes
+    IdentityFile ~/.ssh/id_rsa_yubikey.pub
+EOF
+```
 
-### 4.5f (Optional) Import SSH Keys to `gpg-agent`
+## Connect with public key authentication
 
-If you have existing ssh keys that you wish to make available via `gpg-agent` you'll need to import them. You should then remove the original private keys. When importing the key, `gpg-agent` uses the key's filename as the key's label; this makes it easier to follow where the key originated from. In this example, we're starting with just the Yubikey's key in place and importing `~/.ssh/id_rsa`:
+```
+$ ssh git@github.com -vvv
+[...]
+debug2: key: cardno:000605553211 (0x1234567890),
+debug1: Authentications that can continue: publickey
+debug3: start over, passed a different list publickey
+debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
+debug3: authmethod_lookup publickey
+debug3: remaining preferred: keyboard-interactive,password
+debug3: authmethod_is_enabled publickey
+debug1: Next authentication method: publickey
+debug1: Offering RSA public key: cardno:000605553211
+debug3: send_pubkey_test
+debug2: we sent a publickey packet, wait for reply
+debug1: Server accepts key: pkalg ssh-rsa blen 535
+debug2: input_userauth_pk_ok: fp e5:de:a5:74:b1:3e:96:9b:85:46:e7:28:53:b4:82:c3
+debug3: sign_and_send_pubkey: RSA e5:de:a5:74:b1:3e:96:9b:85:46:e7:28:53:b4:82:c3
+debug1: Authentication succeeded (publickey).
+[...]
+```
 
-    $ ssh-add -l
-    4096 SHA256:... cardno:00060123456 (RSA)
-    $ ssh-add ~/.ssh/id_rsa && rm ~/.ssh/id_rsa
+**Note** To make multiple connections or securely transfer many files, consider using the [ControlMaster](https://en.wikibooks.org/wiki/OpenSSH/Cookbook/Multiplexing) ssh option. Also see [drduh/config/ssh_config](https://github.com/drduh/config/blob/master/ssh_config).
 
-When invoking `ssh-add`, it will prompt for the ssh key's passphrase if present, then the `pinentry` program will prompt and confirm for a new passphrase to use to encrypt the converted key within the gpg key store.
+## Touch to authenticate
 
-The migrated key should be listed in `ssh-add -l`:
+**Note** This is only possible on the Yubikey 4 line.
 
-    $ ssh-add -l
-    4096 SHA256:... cardno:00060123456 (RSA)
-    2048 SHA256:... /Users/username/.ssh/id_rsa (RSA)
+By default, YubiKey will perform key operations without requiring a touch from the user. To require a touch for every SSH connection, use the [YubiKey Manager](https://developers.yubico.com/yubikey-manager/) and Admin PIN:
 
-Or to show the keys with MD5 fingerprints, as used by `gpg-connect-agent`'s `KEYINFO` and `DELETE_KEY` commands:
+    ykman openpgp touch aut on
 
-    $ ssh-add -E md5 -l
-    4096 MD5:... cardno:00060123456 (RSA)
-    2048 MD5:... /Users/username/.ssh/id_rsa (RSA)
+To require a touch for the signing and encrypting keys as well:
 
-When using the key `pinentry` will be invoked to request the key's passphrase. The passphrase will be cached for up to 10 minutes idle time between uses, to a maximum of 2 hours.
+    ykman openpgp touch sig on
+    ykman openpgp touch enc on
 
-## 4.6 SSH - Windows
+The YubiKey will blink when it's waiting for touch.
 
-Begin by exporting your SSH key from GPG:
+## Import SSH keys
 
-	$ gpg --export-ssh-key $USERID
+If there are existing SSH keys that you wish to make available via `gpg-agent`, you'll need to import them. You should then remove the original private keys. When importing the key, `gpg-agent` uses the key's filename as the key's label; this makes it easier to follow where the key originated from. In this example, we're starting with just the YubiKey's key in place and importing `~/.ssh/id_rsa`:
 
+```
+$ ssh-add -l
+4096 SHA256:... cardno:00060123456 (RSA)
 
-Copy this key to a file and keep it for later use. It represents the public SSH key corresponding to the secret key on your YubiKey. You can upload this key to any server you wish to SSH into.
+$ ssh-add ~/.ssh/id_rsa && rm ~/.ssh/id_rsa
+```
 
-To authenticate SSH sessions via our YubiKey we need to enable Gpg4Win's PuTTY integration. Create a file named `gpg-agent.conf` and place it in the directory `C:\%APPDATA%\gnupg`.
-The file should contain the line `enable-putty-support`.
+When invoking `ssh-add`, it will prompt for the ssh key's passphrase if present, then the `pinentry` program will prompt and confirm for a new passphrase to use to encrypt the converted key within the gpg key store.
 
-Then, open a terminal and run the following commands:
+The migrated key should be listed in `ssh-add -l`:
 
-	> gpg-connect-agent killagent /bye
-	> gpg-connect-agent /bye
+```
+$ ssh-add -l
+4096 SHA256:... cardno:00060123456 (RSA)
+2048 SHA256:... /Users/username/.ssh/id_rsa (RSA)
+```
 
-Create a shortcut that points to `gpg-connect-agent /bye` and place it in your startup folder to make sure the agent starts after a system shutdown.
+Or to show the keys with MD5 fingerprints, as used by `gpg-connect-agent`'s `KEYINFO` and `DELETE_KEY` commands:
 
-Now you can use PuTTY for public key SSH authentication. When the server asks for publickey verification, PuTTY will foward the request to GPG, whcih will prompt you for your PIN and authorize the login using your YubiKey.
+```
+$ ssh-add -E md5 -l
+4096 MD5:... cardno:00060123456 (RSA)
+2048 MD5:... /Users/username/.ssh/id_rsa (RSA)
+```
 
-### 4.6a GitHub
+When using the key `pinentry` will be invoked to request the key's passphrase. The passphrase will be cached for up to 10 minutes idle time between uses, to a maximum of 2 hours.
 
-You can use your YubiKey to sign GitHub commits and tags. It can also be used for GitHub SSH authentication, allowing you to push, pull, and commit without your GitHub password.
+## GitHub
 
-Log into GitHub and upload your SSH and PGP public keys.
+You can use YubiKey to sign GitHub commits and tags. It can also be used for GitHub SSH authentication, allowing you to push, pull, and commit without a password.
 
-#### Signing
+Log into GitHub and upload SSH and PGP public keys in Settings.
 
-Then run the following commands:
+To sign:
 
 	> git config --global user.signingkey $KEYID
 
@@ -1351,7 +1374,7 @@ Make sure your user.email option matches the email associated with your PGP iden
 
 Now, to sign commits or tags simply use the `-S` option. GPG will automatically query your YubiKey and prompt you for your PIN.
 
-#### Authentication
+To authenticate:
 
 Run the following commands **(only for Windows)**:
 
@@ -1360,32 +1383,41 @@ Run the following commands **(only for Windows)**:
 You can then change your repository url to:
 `git@github.com:USERNAME/repository`. Any authenticated commands will be authorized by your YubiKey.
 
-**Note:** If you encounter the error `gpg: signing failed: No secret key`, run `gpg --card-status` with your YubiKey plugged in and try the git command again.
+**Note** If you encounter the error `gpg: signing failed: No secret key` - run `gpg --card-status` with YubiKey plugged in and try the git command again.
 
-## 4.7 Requiring touch to authenticate
+## OpenBSD
 
-Note: this is only possible on the Yubikey 4 line.
+Install `pcsc-tools` and enable with `sudo rcctl enable pcscd`, then reboot in order to recognize YubiKey.
 
-By default the Yubikey will perform key operations without requiring a touch from the user. To require a touch for every SSH connection, use the [Yubikey Manager](https://developers.yubico.com/yubikey-manager/) (you'll need the Admin PIN):
+## Windows
 
-    ykman openpgp touch aut on
+Begin by exporting the SSH key from GPG:
 
-To require a touch for the signing and encrypting keys as well:
+```
+$ gpg --export-ssh-key $USERID
+```
 
-    ykman openpgp touch sig on
-    ykman openpgp touch enc on
+Copy this key to a file and keep it for later use. It represents the public SSH key corresponding to the secret key on your YubiKey. You can upload this key to any server you wish to SSH into.
 
-The Yubikey will blink when it's waiting for the touch.
+To authenticate SSH sessions via our YubiKey we need to enable Gpg4Win's PuTTY integration. Create a file named `gpg-agent.conf` and place it in the directory `C:\%APPDATA%\gnupg`.
+The file should contain the line `enable-putty-support`.
 
-### 4.8 OpenBSD
+Then, open a terminal and run the following commands:
+
+```
+> gpg-connect-agent killagent /bye
+> gpg-connect-agent /bye
+```
+
+Create a shortcut that points to `gpg-connect-agent /bye` and place it in your startup folder to make sure the agent starts after a system shutdown.
 
-On OpenBSD, you will need to install `pcsc-tools` and enable with `sudo rcctl enable pcscd`, then reboot in order to recognize the key.
+Now you can use PuTTY for public key SSH authentication. When the server asks for public key verification, PuTTY will foward the request to GPG, whcih will prompt you for your PIN and authorize the login using your YubiKey.
 
-# 5. Troubleshooting
+# Troubleshooting
 
-- If you don't understand some option, read `man gpg`.
+- If you don't understand some option - read `man gpg`.
 
-- If you encounter problems connecting to YubiKey with GPG, simply try unplugging and re-inserting your YubiKey, and restarting the `gpg-agent` process.
+- If you encounter problems connecting to YubiKey with GPG - try unplugging and re-inserting your YubiKey, and restarting the `gpg-agent` process.
 
 - If you receive the error, `gpg: decryption failed: secret key not available` - you likely need to install GnuPG version 2.x.
 
@@ -1407,11 +1439,13 @@ On OpenBSD, you will need to install `pcsc-tools` and enable with `sudo rcctl en
 
 - If you totally screw up, you can [reset the card](https://developers.yubico.com/ykneo-openpgp/ResetApplet.html).
 
-## 5.1 Yubikey OTP Mode and cccccccc....
+# Notes
 
-The Yubikey has two configurations, one invoked with a short press, and the other with a long press. By default the short-press mode is configured for HID OTP - a brief touch will emit an OTP string starting with `cccccccc`. If you rarely use the OTP mode, you can swap it to the second configuration via the Yubikey Personalization tool. If you *never* use OTP, you can disable it entirely using the [Yubikey Manager](https://developers.yubico.com/yubikey-manager) application (note, this not the similarly named Yubikey NEO Manager).
+1. YubiKey has two configurations: one invoked with a short press, and the other with a long press. By default, the short-press mode is configured for HID OTP - a brief touch will emit an OTP string starting with `cccccccc`. If you rarely use the OTP mode, you can swap it to the second configuration via the Yubikey Personalization tool. If you *never* use OTP, you can disable it entirely using the [Yubikey Manager](https://developers.yubico.com/yubikey-manager) application (note, this not the similarly named Yubikey NEO Manager).
+1. Programming YubiKey for GPG keys still lets you use its two configurations - [OTP](https://www.yubico.com/faq/what-is-a-one-time-password-otp/) and [static password](https://www.yubico.com/products/services-software/personalization-tools/static-password/) modes, for example.
+1. Setting an expiry essentially forces you to manage your subkeys and announces to the rest of the world that you are doing so. Setting an expiry on a primary key is ineffective for protecting the key from loss - whoever has the primary key can simply extend its expiry period. Revocation certificates are [better suited](https://security.stackexchange.com/questions/14718/does-openpgp-key-expiration-add-to-security/79386#79386) for this purpose. It may be appropriate for your use case to set expiry dates on subkeys.
 
-# 6. References and similar work
+# Similar work
 
 * https://developers.yubico.com/yubikey-personalization/
 * https://developers.yubico.com/PGP/Card_edit.html