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Add section to quickly create keys
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apiraino committed Apr 15, 2022
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80 changes: 79 additions & 1 deletion README.md
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Expand Up @@ -29,6 +29,7 @@ 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)
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## Add extra identities

(Optional) To add additional email addresses or identities, use `adduid`:
(Optional) To add additional email addresses or identities, use `adduid`.

First open the keyring:
```console
$ gpg --expert --edit-key $KEYID
```

Then add the new identity:
```console
gpg> adduid
Real name: Dr Duh
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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:
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2 changes: 1 addition & 1 deletion contrib/gen-params-ed25519
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Expand Up @@ -21,7 +21,7 @@ Key-Usage: cert

# select a name and email address - neither has to be valid nor existing
Name-Real: Dr Duh
Name-Email: <doc@duh.to>
Name-Email: doc@duh.to

# Do not set the key to expire
Expire-Date: 0
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2 changes: 1 addition & 1 deletion contrib/gen-params-rsa4096
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Expand Up @@ -18,7 +18,7 @@ Key-Usage: cert

# select a name and email address - neither has to be valid nor existing
Name-Real: Dr Duh
Name-Email: <doc@duh.to>
Name-Email: doc@duh.to

# Do not set the key to expire
Expire-Date: 0
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