I manage my backups with duply. Today I wanted to fetch some backuped files from an old machine that got lost on my current machine. Unfortunately I got the error that the storage was signed with another key than the key which was autoselected by duply:
Autoset found secret key of first GPG_KEY entry 'B8C46F4D410B8E334BBA1ECA68D101873E261004' for signing. … Datenträger wurde von Schlüssel 68D101873E261004, anstatt von B8C46F4D410B8E334BBA1ECA68D101873E261004 unterschrieben
(sorry for the 2. message in German but it says what I've just described)
The curious thing is that I am convinced that it is the same key. First, I haven't changed any key duply copied into the profile folder when I created the profile. Second, the numbers of the signing key used by the storag (first key number) is just the last part of the key that was autoselected by duply from the profile folder. Thus, I do not understand what really is happening here.
The keys which were stored by duply in the profile folder during profile generation look like this:
$ ls gpgkey.B8C4_6F4D_410B_8E33_4BBA_1ECA_68D1_0187_3E26_1004.pub.asc gpgkey.B8C46F4D410B8E334BBA1ECA68D101873E261004.pub.asc gpgkey.B8C4_6F4D_410B_8E33_4BBA_1ECA_68D1_0187_3E26_1004.sec.asc gpgkey.B8C46F4D410B8E334BBA1ECA68D101873E261004.sec.asc
which looks kind of redundant as well.
In my duply profile config, it says
Another thing is, that I did not have any trouble when I used the setup the last time and since then I haven't changed anything manually