Can’t sign another user’s key

Dominik Hoffmann's Avatar

Dominik Hoffmann

23 Nov, 2022 03:33 AM

Which of our tools is giving you problems?

GPG Keychain

Attach a screenshot of the version info for all installed components (how to:

The screenshot of the alert is attached. The wording of the alert text is

Signing failed.

Sign userlD failed! (Invalid digest algorithm)

Code = 5

Error text:

gpg: Note: third-party key signatures using the SHA1 algorithm are rejected

gpg: signing failed: Invalid digest algorithm gpg: signing failed: Invalid digest algorithm

Describe your problem. Add as much detail as possible.

When I try to sign another user’s key, which I have imported into GPG Keychain, after successfully inputting my passphrase, the alert comes up.

What did you expect instead

I expected the target key to have been signed and submitted to the key server.

Describe steps leading to the problem.

  1. Select public key to be signed.
  2. Right-click on it.
  3. Select “Sign….”
  4. In the next dialog select the “Publish” checkbox and hit the “Sign” button.
  5. The error alert comes up.

Are you using any other plugins?


P.S.: Upon request from developers I can provide a system report.

  1. Support Staff 1 Posted by Steve on 23 Nov, 2022 08:25 PM

    Steve's Avatar

    Hi Dominik,

    welcome to the GPGTools support platform. Sorry to hear you are having problems using GPG Suite.

    The error message Invalid digest algorithm along the note Third-party key signatures using the SHA1 algorithm are rejected indicates, that the algorithm preferences for your key are outdated or your key is too old to support better algorithms.

    To check your algorithm preferences you need to enable expert settings. Then select the key and in the menubar Key > Algorithm Preferences…. Make sure to disable the expert settings once you are done.

    Feel free to send a screenshot of your algorithm preferences view along with the key details after double-clicking your sec/pub key in GPG Keychain.

    All the best,

  2. Steve closed this discussion on 09 Feb, 2023 12:31 AM.

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