Error: There is no assurance this key belongs to the named user

[Jens Tröger]

Hello,

I’ve been happily using `pass` for many years, and have been keeping up-to-date using MacPorts: https://ports.macports.org/port/pass/

A few weeks ago, however, when I wanted to edit an existing entry, I received the following error:

    jens at pooh ~ > pass edit Some/Entry
    gpg: WARNING: server 'gpg-agent' is older than us (2.5.17 < 2.5.18)
    gpg: 81............98: There is no assurance this key belongs to the named user
    gpg: /var/folders/2r/yyz1661s4j91vhdkzktg66z80000gn/T//pass.kF4Gb3qAp07WP/QHBHgP-Some-Entry: encryption failed: Unusable public key
    GPG encryption failed. Would you like to try again? [y/N] n

In the past I could just ignore the first line WARNING and update at a later point; that had no impact on using the agent. But now, with this error, I’m able to `pass show` but both `pass generate` and `pass edit` stopped working.

When I list the keys associated with that “faulty” one:

    jens at pooh ~ > gpg -k 81............98
    pub   rsa4096 2017-04-18 [SC]
          1E1..................................EA7
    uid           [ unknown] Jens Tröger <jens.troeger at light-speed.de>
    sub   rsa4096 2017-04-18 [E]
          09D..................................798

and when I manually use the subkey to encrypt something I get the same error:

    jens at pooh ~ > gpg --recipient 09D..................................798 --encrypt --armor
    gpg: 81............98: There is no assurance this key belongs to the named user

    sub  rsa4096/81............98 2017-04-18 Jens Tröger <jens.troeger at light-speed.de>
          1E1..................................EA7
          09D..................................798

    It is NOT certain that the key belongs to the person named
    in the user ID.  If you *really* know what you are doing,
    you may answer the next question with yes.

    Use this key anyway? (y/N) y
    Hello
    ^D

So this works, although I get that exact same warning.

Now the question I have is: how can I fix this? And what happened here, why did that subkey suddenly (?) stop working?

Any insight would be appreciated, thank you!
Jens