More entropy cleanup, move batch instructions to alt

1 files changed, 68 insertions, 87 deletions

diff --git a/README.md b/README.md
index ba709f3..ce99cb7 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@ This is a guide to using [YubiKey](https://www.yubico.com/products/yubikey-hardw
 
 Keys stored on YubiKey are [non-exportable](http://web.archive.org/web/20201125172759/https://support.yubico.com/hc/en-us/articles/360016614880-Can-I-Duplicate-or-Back-Up-a-YubiKey-) (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. All signing and encryption operations happen on the card, rather than in OS memory.
 
-**New!** [drduh/Purse](https://github.com/drduh/Purse) is a password manager which uses GPG and YubiKey.
+**Tip** [drduh/Purse](https://github.com/drduh/Purse) is a password manager which uses GPG and YubiKey to securely store and read credentials.
 
 > **Security Note**: If you followed this guide before Jan 2021, your GPG *PIN* and *Admin PIN* may be set to their default values (`123456` and `12345678` respectively). This would allow an attacker to use your Yubikey or reset your PIN. Please see the [Change PIN](#change-pin) section for details on how to change your PINs.
 
@@ -30,7 +30,6 @@ If you have a comment or suggestion, please open an [Issue](https://github.com/d
   * [Encryption](#encryption)
   * [Authentication](#authentication)
   * [Add extra identities](#add-extra-identities)
-- [Create keys with --batch and --quick-add-key](#create-keys-with---batch-and---quick-add-keys)
 - [Verify](#verify)
 - [Export secret keys](#export-secret-keys)
 - [Revocation certificate](#revocation-certificate)
@@ -86,6 +85,7 @@ If you have a comment or suggestion, please open an [Issue](https://github.com/d
 - [Notes](#notes)
 - [Troubleshooting](#troubleshooting)
 - [Alternatives](#alternatives)
+  * [Create keys with batch](#create-keys-with-batch)
 - [Links](#links)
 
 
@@ -470,33 +470,27 @@ You may also need more recent versions of [yubikey-personalization](https://deve
 
 Generating cryptographic keys requires high-quality [randomness](https://www.random.org/randomness/), measured as entropy.
 
-Most operating systems use software-based pseudorandom number generators. On newer machines there are CPU based hardware random number generators (HRNG) or you can use a separate hardware device like the White Noise or [OneRNG](https://onerng.info/onerng/) will [increase the speed](https://lwn.net/Articles/648550/) of entropy generation and possibly the quality.
+Most operating systems use software-based pseudorandom number generators or CPU-based hardware random number generators (HRNG).
 
-YubiKey firmware version 5.2.3 introduced "Enhancements to OpenPGP 3.4 Support" - which can optionally gather additional entropy from YubiKey via the SmartCard interface.
+Optionally, you can use a separate hardware device like [OneRNG](https://onerng.info/onerng/) to [increase the speed](https://lwn.net/Articles/648550/) of entropy generation and possibly also the quality.
 
 ## YubiKey
 
-To feed the system's PRNG with entropy generated by the YubiKey itself, issue:
+YubiKey firmware version 5.2.3 introduced "Enhancements to OpenPGP 3.4 Support" - which can optionally gather additional entropy from YubiKey via the SmartCard interface.
+
+To seed the kernel's PRNG with additional 512 bytes retrieved from the YubiKey:
 
 ```console
 $ echo "SCD RANDOM 512" | gpg-connect-agent | sudo tee /dev/random | hexdump -C
 ```
 
-This will seed the Linux kernel's PRNG with additional 512 bytes retrieved from the YubiKey.
-
 ## OneRNG
 
 Install [rng-tools](https://wiki.archlinux.org/index.php/Rng-tools) software:
 
 ```console
 $ sudo apt -y install at rng-tools python3-gnupg openssl
-```
-
-If you have a hardware device other than the CPU based one, install the accompany software and point rng-tools to its `/dev/` device.
 
-OneRNG specific example:
-
-```
 $ wget https://github.com/OneRNG/onerng.github.io/raw/master/sw/onerng_3.7-1_all.deb
 
 $ sha256sum onerng_3.7-1_all.deb
@@ -577,7 +571,7 @@ $ gpg --gen-random --armor 0 24
 ydOmByxmDe63u7gqx2XI9eDgpvJwibNH
 ```
 
-Use upper case letters for improved readability if they are written down:
+Use upper case letters for improved readability if passwords are written down by hand:
 
 ```console
 $ LC_ALL=C tr -dc '[:upper:]' < /dev/urandom | fold -w 20 | head -n1
@@ -1010,77 +1004,6 @@ gpg> save
 
 By default, the last identity added will be the primary user ID - use `primary` to change that.
 
-# Create keys with `--batch` and `--quick-add-keys`
-
-To remove some complexity from the process, we will show an alternate procedure to generate the keys using template files and the `--batch` parameter. For futher details, full GNUPG documentation can be found [at this link](https://www.gnupg.org/documentation/manuals/gnupg/Unattended-GPG-key-generation.html). This procedure will have just the same result as described above.
-
-For your convenience you can start from this RSA4096 key template: [gen-params-rsa4096](contrib/gen-params-rsa4096). If you're using GnuPG v2.1.7 or newer we strongly recommend generating ED25519 keys ([gen-params-ed25519](contrib/gen-params-ed25519), the procedure is the same). These templates will not set the master key to expire - see [Note #3](#notes).
-
-Generate a RSA4096 master key:
-
-```console
-$ gpg --batch --generate-key gen-params-rsa4096
-gpg: Generating a basic OpenPGP key
-gpg: key 0xEA5DE91459B80592 marked as ultimately trusted
-gpg: revocation certificate stored as '/tmp.FLZC0xcM/openpgp-revocs.d/D6F924841F78D62C65ABB9588B461860159FFB7B.rev'
-gpg: done
-```
-
-Let's check the result:
-
-```console
-$ gpg --list-key
-gpg: checking the trustdb
-gpg: marginals needed: 3  completes needed: 1  trust model: pgp
-gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
-/tmp.FLZC0xcM/pubring.kbx
--------------------------------
-pub   rsa4096/0xFF3E7D88647EBCDB 2021-08-22 [C]
-       Key fingerprint = 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
-uid                   [ultimate] Dr Duh <doc@duh.to>
-```
-
-The key fingerprint (`011C E16B D45B 27A5 5BA8 776D FF3E 7D88 647E BCDB`) will be used to create the three subkeys for signing, authentication and encryption.
-
-Now create the three subkeys for signing, authentication and encryption. Use a 1 year expiration for sub-keys - they can be renewed using the offline master key, see [rotating keys](#rotating-keys).
-
-We will use the the quick key manipulation interface of GNUPG (with `--quick-add-key`), see [the documentation](https://www.gnupg.org/documentation/manuals/gnupg/Unattended-GPG-key-generation.html#Unattended-GPG-key-generation).
-
-Create a [signing subkey](https://stackoverflow.com/questions/5421107/can-rsa-be-both-used-as-encryption-and-signature/5432623#5432623):
-
-```console
-$ gpg --quick-add-key "011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB" \
-  rsa4096 sign 1y
-```
-
-Now create an [encryption subkey](https://www.cs.cornell.edu/courses/cs5430/2015sp/notes/rsa_sign_vs_dec.php):
-
-```console
-$ gpg --quick-add-key "011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB" \
-  rsa4096 encrypt 1y
-```
-
-Finally, create an [authentication subkey](https://superuser.com/questions/390265/what-is-a-gpg-with-authenticate-capability-used-for):
-
-```console
-$ gpg --quick-add-key "011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB" \
-  rsa4096 auth 1y
-```
-
-Let's check the final result:
-
-```console
-$ gpg --list-keys
-/tmp.FLZC0xcM/pubring.kbx
--------------------------------
-pub   rsa4096/0xFF3E7D88647EBCDB 2021-08-22 [C]
-      Key fingerprint = 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
-uid                   [ultimate] Dr Duh <doc@duh.to>
-sub   rsa4096/0xBECFA3C1AE191D15 2017-10-09 [S] [expires: 2018-10-09]
-sub   rsa4096/0x5912A795E90DD2CF 2017-10-09 [E] [expires: 2018-10-09]
-sub   rsa4096/0x3F29127E79649A3D 2017-10-09 [A] [expires: 2018-10-09]
-```
-
 # Verify
 
 List the generated secret keys and verify the output:
@@ -1727,7 +1650,7 @@ $ cp -avi /mnt/encrypted-storage/tmp.XXX $GNUPGHOME
 $ cd $GNUPGHOME
 ```
 
-## Switching between two or more Yubikeys.
+## Switching between two or more Yubikeys
 	
 When you add a GPG key to a Yubikey using the *keytocard* command, GPG deletes the key from your keyring and adds a *stub* pointing to that exact Yubikey (the stub identifies the GPG KeyID and the Yubikey's serial number).
 	
@@ -1861,7 +1784,7 @@ sub  4096R/0x3F29127E79649A3D  created: 2017-10-09  expires: 2018-10-09  usage:
 gpg> quit
 ```
 
-Remove and re-insert YubiKey and check the status:
+Remove and re-insert YubiKey and verify the status:
 
 ```console
 $ gpg --card-status
@@ -2942,6 +2865,64 @@ Before you unmount your backup, ask yourself if you should make another one just
 * [`piv-agent`](https://github.com/smlx/piv-agent) is an SSH and GPG agent which you can use with your PIV hardware security device (e.g. a Yubikey).
 * [`keytotpm`](https://www.gnupg.org/documentation/manuals/gnupg/OpenPGP-Key-Management.html) is an option to use GnuPG with TPM systems.
 
+## Create keys with batch
+
+Keys can also be generated using template files and the `--batch` parameter - see [GnuPG documentation](https://www.gnupg.org/documentation/manuals/gnupg/Unattended-GPG-key-generation.html)
+
+Start from the [gen-params-rsa4096](contrib/gen-params-rsa4096) template. If you're using GnuPG v2.1.7 or newer, you can also use the ([gen-params-ed25519](contrib/gen-params-ed25519) template. These templates will not set the master key to expire - see [Note #3](#notes).
+
+Generate master key:
+
+```console
+$ gpg --batch --generate-key gen-params-rsa4096
+gpg: Generating a basic OpenPGP key
+gpg: key 0xEA5DE91459B80592 marked as ultimately trusted
+gpg: revocation certificate stored as '/tmp.FLZC0xcM/openpgp-revocs.d/D6F924841F78D62C65ABB9588B461860159FFB7B.rev'
+gpg: done
+```
+
+Verify the result:
+
+```console
+$ gpg --list-key
+gpg: checking the trustdb
+gpg: marginals needed: 3  completes needed: 1  trust model: pgp
+gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
+/tmp.FLZC0xcM/pubring.kbx
+-------------------------------
+pub   rsa4096/0xFF3E7D88647EBCDB 2021-08-22 [C]
+       Key fingerprint = 011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB
+uid                   [ultimate] Dr Duh <doc@duh.to>
+```
+
+The key fingerprint (`011C E16B D45B 27A5 5BA8 776D FF3E 7D88 647E BCDB`) will be used to create the three subkeys for signing, authentication and encryption.
+
+Now create the three subkeys for signing, authentication and encryption. Use a 1 year expiration for sub-keys - they can be renewed using the offline master key, see [rotating keys](#rotating-keys).
+
+We will use the the quick key manipulation interface of GNUPG (with `--quick-add-key`), see [the documentation](https://www.gnupg.org/documentation/manuals/gnupg/Unattended-GPG-key-generation.html#Unattended-GPG-key-generation).
+
+Create a [signing subkey](https://stackoverflow.com/questions/5421107/can-rsa-be-both-used-as-encryption-and-signature/5432623#5432623):
+
+```console
+$ gpg --quick-add-key "011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB" \
+  rsa4096 sign 1y
+```
+
+Now create an [encryption subkey](https://www.cs.cornell.edu/courses/cs5430/2015sp/notes/rsa_sign_vs_dec.php):
+
+```console
+$ gpg --quick-add-key "011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB" \
+  rsa4096 encrypt 1y
+```
+
+Finally, create an [authentication subkey](https://superuser.com/questions/390265/what-is-a-gpg-with-authenticate-capability-used-for):
+
+```console
+$ gpg --quick-add-key "011C E16B D45B 27A5 5BA8  776D FF3E 7D88 647E BCDB" \
+  rsa4096 auth 1y
+```
+
+
 # Links
 
 * https://alexcabal.com/creating-the-perfect-gpg-keypair/