gpg is the OpenPGP part of the GNU Privacy Guard (GnuPG). It is a tool to provide digital encryption and signing services using the OpenPGP standard. You can use the gpg command for complete key management including setting up keys, change key passphrase, list keys and much more.
Change the passphrase of the secret key
The syntax is:
gpg --edit-key Your-Key-ID-Here
You need type the passwd command followed by the save command at gpg> prompt to change the passphrase for your key-ID.
First, list your keys with the following command:
/root/.gnupg/pubring.gpg ------------------------ pub 4096R/9AABBCD8 2013-10-04 uid Home Nas Server (Home Nas Server Backup)
sub 4096R/149D60C7 2013-10-04
You need to note down the public key 9AABBCD8. Next, type the following command:
gpg --edit-key 9AABBCD8
gpg (GnuPG) 1.4.12; Copyright (C) 2012 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/9AABBCD8 created: 2013-10-04 expires: never usage: SC trust: ultimate validity: ultimate sub 4096R/149D60C7 created: 2013-10-04 expires: never usage: E [ultimate] (1). Home Nas Server (Home Nas Server Backup)
Type the passwd command at gpg> prompt to change the passphrase:
You need to supply old passphrase to unlock the secret key:
Key is protected.
You need a passphrase to unlock the secret key for user: "Home Nas Server (Home Nas Server Backup)
" 4096-bit RSA key, ID 9AABBCD8, created 2013-10-04
Enter passphrase: TYPE-YOUR-OLD-PASSPHRASE-HERE
Finally, enter the new passphrase:
Enter the new passphrase for this secret key.
Enter passphrase: TYPE-YOUR-new-PASSPHRASE-HERE Repeat passphrase: again-TYPE-YOUR-new-PASSPHRASE-HERE
To save all changes to the key rings and quit, type save at gpg> prompt:
For more information read gpg(1) man page.