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Apparently, there are some problems with the new defaults that are set when one creates a PGP key using a recent version of GnuPG (2.4).

I ran into this after generating a new ECC/ED25519 key to replace my "old" RSA one. The problem showed up when I re-encrypted my pass password store passwords with the new key: After transferring the key to my Android phone and importing it into OpenKeychain, I could not decrypt any passwords anymore.

After some research, I found https://github.com/open-keychain/open-keychain/issues/2886, describing this exact issue. As a possible fix, disabling the unsupported AEAD mechanism in the key itself was mentioned.

I'm not that deep into cryptography. I'm not sure I completely grasp what AEAD and OCB mean.

So: Is it wise and/or necessary to disable that for new GnuPG generated keys, for the sake of interoperability? Or will the others catch up and implement it? Or is there a good reason not to do so? Should one keep using legacy RSA keys? Is it too early to switch to more modern ones?

Thanks to all cryptography experts for all clarification!

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  • en.wikipedia.org/wiki/… and more specifically en.wikipedia.org/wiki/OCB_mode are relatively recent advances that provide more robust integrity protection against possible tampering of your data than the standard-OpenPGP MDC (Manipulation Detection Code), but for data you don't exchange with other people/systems (and I sure hope you aren't sending your password file to other people!) this is probably unnecessary. If you want to go into this in more detail, security.SX is probably more suitable. ...
    – dave_thompson_085
    Commented Mar 4 at 0:58
  • ... Note this is independent of the keypair(s). You can use AEAD/OCB on any of RSA DSA/EG or ECC keypairs, and you can use not-AEAD/OCB on any of them. Ed25519 cannot encrypt, but is usually used with a cv25519 subkey; as long as your systems (all) support these, they are considered quite secure.
    – dave_thompson_085
    Commented Mar 4 at 1:03
  • Thanks for the hints. I'll ask at security.SX additionally as you advised.
    – Tobias Leupold
    Commented Mar 4 at 6:27
  • A nice answer was given there: security.stackexchange.com/questions/275883/…
    – Tobias Leupold
    Commented Mar 5 at 13:24

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