Merge pull request #91 from kalbasit/yubikey_improve-security

Master key should have Certify-capability only!
pull/94/head
drduh 5 years ago committed by GitHub
commit ae3e9703f9
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23

@ -206,17 +206,53 @@ $ gpg --gen-random -a 0 24
ydOmByxmDe63u7gqx2XI9eDgpvJwibNH
```
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](#notes).
Generate a new key with GPG, selecting `(8) RSA (set your own capabilities)`, `Certify`-only and `4096` bit keysize. Do not set the key to expire - see [Note #3](#notes).
```console
$ gpg --full-generate-key
$ gpg --expert --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
(7) DSA (set your own capabilities)
(8) RSA (set your own capabilities)
(9) ECC and ECC
(10) ECC (sign only)
(11) ECC (set your own capabilities)
(13) Existing key
Your selection? 8
Possible actions for a RSA key: Sign Certify Encrypt Authenticate
Current allowed actions: Sign Certify 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 Certify Encrypt Authenticate
Current allowed actions: Sign Certify
(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 Certify Encrypt Authenticate
Current allowed actions: Certify
(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
@ -252,7 +288,7 @@ 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]
pub rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [C]
Key fingerprint = 011C E16B D45B 27A5 5BA8 776D FF3E 7D88 647E BCDB
uid Dr Duh <doc@duh.to>
```
@ -275,7 +311,7 @@ $ gpg --expert --edit-key $KEYID
Secret key is available.
sec rsa4096/0xEA5DE91459B80592
created: 2017-10-09 expires: never usage: SC
created: 2017-10-09 expires: never usage: C
trust: ultimate validity: ultimate
[ultimate] (1). Dr Duh <doc@duh.to>
```
@ -323,10 +359,10 @@ 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
created: 2017-10-09 expires: never usage: C
trust: ultimate validity: ultimate
ssb rsa4096/0xBECFA3C1AE191D15
created: 2017-10-09 expires: 2018-10-09 usage: S
created: 2017-10-09 expires: 2018-10-09 usage: S
[ultimate] (1). Dr Duh <doc@duh.to>
```
@ -367,12 +403,12 @@ 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
created: 2017-10-09 expires: never usage: C
trust: ultimate validity: ultimate
ssb rsa4096/0xBECFA3C1AE191D15
created: 2017-10-09 expires: 2018-10-09 usage: S
created: 2017-10-09 expires: 2018-10-09 usage: S
ssb rsa4096/0x5912A795E90DD2CF
created: 2017-10-09 expires: 2018-10-09 usage: E
created: 2017-10-09 expires: 2018-10-09 usage: E
[ultimate] (1). Dr Duh <doc@duh.to>
```
@ -455,14 +491,14 @@ 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
created: 2017-10-09 expires: never usage: C
trust: ultimate validity: ultimate
ssb rsa4096/0xBECFA3C1AE191D15
created: 2017-10-09 expires: 2018-10-09 usage: S
created: 2017-10-09 expires: 2018-10-09 usage: S
ssb rsa4096/0x5912A795E90DD2CF
created: 2017-10-09 expires: 2018-10-09 usage: E
created: 2017-10-09 expires: 2018-10-09 usage: E
ssb rsa4096/0x3F29127E79649A3D
created: 2017-10-09 expires: 2018-10-09 usage: A
created: 2017-10-09 expires: 2018-10-09 usage: A
[ultimate] (1). Dr Duh <doc@duh.to>
gpg> save
@ -476,7 +512,7 @@ List the generated secret keys and verify the output:
$ gpg --list-secret-keys
/tmp.FLZC0xcM/pubring.kbx
-------------------------------------------------------------------------
sec rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [SC]
sec rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [C]
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]
@ -782,14 +818,14 @@ $ gpg --edit-key $KEYID
Secret key is available.
sec rsa4096/0xFF3E7D88647EBCDB
created: 2017-10-09 expires: never usage: SC
created: 2017-10-09 expires: never usage: C
trust: ultimate validity: ultimate
ssb rsa4096/0xBECFA3C1AE191D15
created: 2017-10-09 expires: 2018-10-09 usage: S
created: 2017-10-09 expires: 2018-10-09 usage: S
ssb rsa4096/0x5912A795E90DD2CF
created: 2017-10-09 expires: 2018-10-09 usage: E
created: 2017-10-09 expires: 2018-10-09 usage: E
ssb rsa4096/0x3F29127E79649A3D
created: 2017-10-09 expires: 2018-10-09 usage: A
created: 2017-10-09 expires: 2018-10-09 usage: A
[ultimate] (1). Dr Duh <doc@duh.to>
```
@ -801,7 +837,7 @@ Select and move the signature key. You will be prompted for the key passphrase a
gpg> key 1
sec rsa4096/0xFF3E7D88647EBCDB
created: 2017-10-09 expires: never usage: SC
created: 2017-10-09 expires: never usage: C
trust: ultimate validity: ultimate
ssb* rsa4096/0xBECFA3C1AE191D15
created: 2017-10-09 expires: 2018-10-09 usage: S
@ -832,7 +868,7 @@ gpg> key 1
gpg> key 2
sec rsa4096/0xFF3E7D88647EBCDB
created: 2017-10-09 expires: never usage: SC
created: 2017-10-09 expires: never usage: C
trust: ultimate validity: ultimate
ssb rsa4096/0xBECFA3C1AE191D15
created: 2017-10-09 expires: 2018-10-09 usage: S
@ -860,7 +896,7 @@ gpg> key 2
gpg> key 3
sec rsa4096/0xFF3E7D88647EBCDB
created: 2017-10-09 expires: never usage: SC
created: 2017-10-09 expires: never usage: C
trust: ultimate validity: ultimate
ssb rsa4096/0xBECFA3C1AE191D15
created: 2017-10-09 expires: 2018-10-09 usage: S
@ -886,7 +922,7 @@ Verify the subkeys have moved to YubiKey as indicated by `ssb>`:
$ gpg --list-secret-keys
/tmp.FLZC0xcM/pubring.kbx
-------------------------------------------------------------------------
sec rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [SC]
sec rsa4096/0xFF3E7D88647EBCDB 2017-10-09 [C]
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]
@ -1008,7 +1044,7 @@ $ gpg --edit-key $KEYID
Secret key is available.
gpg> trust
pub 4096R/0xFF3E7D88647EBCDB created: 2016-05-24 expires: never usage: SC
pub 4096R/0xFF3E7D88647EBCDB created: 2016-05-24 expires: never usage: C
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
@ -1028,7 +1064,7 @@ Please decide how far you trust this user to correctly verify other users' keys
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
pub 4096R/0xFF3E7D88647EBCDB created: 2016-05-24 expires: never usage: C
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
@ -1081,7 +1117,7 @@ ssb> 4096R/0x3F29127E79649A3D created: 2017-10-09 expires: 2018-10-09
# Encryption
```console
$ echo "test message string" | gpg --encrypt --armor --recipient $KEYID
$ echo "test message string" | gpg --encrypt --armor --recipient $KEYID
-----BEGIN PGP MESSAGE-----
hQIMA1kSp5XpDdLPAQ/+JyYfLaUS/+llEzQaKDb5mWhG4HlUgD99dNJUXakm085h
@ -1386,7 +1422,7 @@ $ scp ~/.gnupg/pubring.kbx remote:~/.gnupg/
* Finally, to enable agent forwarding for a given machine, add the following to the local machine's ssh config file `~/.ssh/config` (your agent sockets may be different):
```
Host
Host
Hostname your-domain
ForwardAgent yes
RemoteForward /run/user/1000/gnupg/S.gpg-agent /run/user/1000/gnupg/S.gpg-agent.extra

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