まずは現在の鍵の情報を確認。今のところ副鍵は1つ。
$ gpg --list-key XXXXXXXX pub 4096R/XXXXXXXX 2012-02-10 uid AYANOKOUZI, Ryuunosuke uid AYANOKOUZI, Ryuunosuke <i38w7i3@yahoo.co.jp> sub 4096R/YYYYYYYY 2012-02-10
この鍵に副鍵を追加する。途中でこの鍵のパスフレーズと、新しい副鍵のパスフレーズを聞かれる。
$ gpg --edit-key XXXXXXXX
gpg (GnuPG) 1.4.10; Copyright (C) 2008 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.
Secret key is available.
pub 4096R/XXXXXXXX created: 2012-02-10 expires: never usage: SC
trust: ultimate validity: ultimate
sub 4096R/YYYYYYYY created: 2012-02-10 expires: never usage: E
[ultimate] (1). AYANOKOUZI, Ryuunosuke
[ultimate] (2) AYANOKOUZI, Ryuunosuke <i38w7i3@yahoo.co.jp>
gpg> addkey
Key is protected.
You need a passphrase to unlock the secret key for
user: "AYANOKOUZI, Ryuunosuke"
4096-bit RSA key, ID XXXXXXXX, created 2012-02-10
Please select what kind of key you want:
(3) DSA (sign only)
(4) RSA (sign only)
(5) Elgamal (encrypt only)
(6) RSA (encrypt only)
Your selection?
Invalid selection.
Your selection? 4
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048)
Requested keysize is 2048 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)
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.
Not enough random bytes available. Please do some other work to give
the OS a chance to collect more entropy! (Need 281 more bytes)
..........+++++
..+++++
pub 4096R/XXXXXXXX created: 2012-02-10 expires: never usage: SC
trust: ultimate validity: ultimate
sub 4096R/YYYYYYYY created: 2012-02-10 expires: never usage: E
sub 2048R/ZZZZZZZZ created: 2012-02-10 expires: never usage: S
[ultimate] (1). AYANOKOUZI, Ryuunosuke
[ultimate] (2) AYANOKOUZI, Ryuunosuke <i38w7i3@yahoo.co.jp>
gpg> quit
Save changes? (y/N) y
最後に変更内容の確認。副鍵が追加されたことがわかる。
$ gpg --list-key XXXXXXXX pub 4096R/XXXXXXXX 2012-02-10 uid AYANOKOUZI, Ryuunosuke uid AYANOKOUZI, Ryuunosuke <i38w7i3@yahoo.co.jp> sub 4096R/YYYYYYYY 2012-02-10 sub 2048R/ZZZZZZZZ 2012-02-10