[Duplicity-talk] 0.5.18 weird GPG error ([key_I_dont_mention] unusable public key)

[Andrew Kohlsmith (Mailing List Account)]

Good morning,

I am running into an unusual problem with duplicity. It fails when doing a 
full backup, stating that a key has no indication that it really belongs to 
the owner, followed by an "encryption failed: unusable public key" error.

The problem is that the fingerprint it's giving me as being the problem is NOT 
one that I have specified!

My command line:
# duplicity --full-if-older-than 26W --archive-dir 
/var/data/duplicity/archivedir/test --encrypt-key KEYONE --encrypt-key KEYTWO 
--encrypt-key KEYTHREE /var/data/cvs file:///var/data/duplicity/test            
                                 

obviously KEYONE, KEYTWO and KEYTHREE are my GPG keys. (I encrypt to my 
personal key, a backup key, and a company key.)

The backup fails almost immediately with the following message:

Last full backup date: none                                                     
          
Last full backup is too old, forcing full backup
Exception in thread wait26030:
Traceback (most recent call last):
  File "/usr/lib/python2.3/threading.py", line 436, in __bootstrap
    self.run()
  File "/usr/lib/python2.3/threading.py", line 416, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib/python2.3/site-packages/duplicity/GnuPGInterface.py", line 
668, in threaded_waitpid
    process.returned = os.waitpid(process.pid, 0)[1]
OSError: [Errno 10] No child processes

Exception in thread wait26027:
Traceback (most recent call last):
  File "/usr/lib/python2.3/threading.py", line 436, in __bootstrap
    self.run()
  File "/usr/lib/python2.3/threading.py", line 416, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib/python2.3/site-packages/duplicity/GnuPGInterface.py", line 
668, in threaded_waitpid
    process.returned = os.waitpid(process.pid, 0)[1]
OSError: [Errno 10] No child processes

GPGError: GPG Failed, see log below:
===== Begin GnuPG log =====
gpg: FF873F7F: There is no indication that this key really belongs to the 
owner
gpg: [stdin]: encryption failed: unusable public key
===== End GnuPG log =====

Now the curious part is that that key, FF873F7F, is NOT one I have specified on 
my command line.  After some initial debugging, I have found the source of 
that key.  It's a "sub" key on my personal signing/encryption key:

# gpg --list-key EAF7ACB0
pub  1024D/EAF7ACB0 2001-08-27 Andrew Kohlsmith <address@hidden>
uid                            Andrew Kohlsmith <address@hidden>
uid                            Andrew Kohlsmith (mailing lists account) 
<address@hidden>
sub  2048g/FF873F7F 2001-08-27

Now I don't have any problem with this key with anything else; why is 
duplicity unhappy?

-A.