From an issue raised on Stack Exchange (https://security.stackexchange.com/questions/248320/how-to-properly-export-and-re-import-gpg-secret-key-and-all-its-subkeys)
When a batch mode key is created with "Subkey-Type: ECC" and "Subkey-Curve: Ed25519", the key is generated without errors and appears to function normally. However, importing the secret keys will yield an unusable secret subkey: $ gpg --batch --gen-key <<EOF > Key-Type: default > Subkey-Type: ECC > Subkey-Curve: Ed25519 > Name-Real: testkey > EOF gpg: key 4C95665DD06F8126 marked as ultimately trusted gpg: revocation certificate stored as '/home/me/.gnupg/openpgp-revocs.d/1CB8F79F656BCD71BF9A89694C95665DD06F8126.rev' $ gpg -K gpg: checking the trustdb gpg: marginals needed: 3 completes needed: 1 trust model: pgp gpg: depth: 0 valid: 2 signed: 0 trust: 0-, 0q, 0n, 0m, 0f, 2u /home/me/.gnupg/pubring.kbx ----------------------------- sec rsa3072 2021-04-17 [SC] 1CB8F79F656BCD71BF9A89694C95665DD06F8126 uid [ultimate] testkey ssb ed25519 2021-04-17 [E] $ gpg -ao test --export-secret-keys 1CB8F79F656BCD71BF9A89694C95665DD06F8126 $ gpg --yes --delete-secret-and-public-keys 1CB8F79F656BCD71BF9A89694C95665DD06F8126 $ gpg --import test gpg: key 4C95665DD06F8126: public key "testkey" imported gpg: key 4C95665DD06F8126: secret key imported gpg: Total number processed: 1 gpg: imported: 1 gpg: secret keys read: 1 gpg: secret keys imported: 1 $ gpg -K /home/me/.gnupg/pubring.kbx ----------------------------- sec rsa3072 2021-04-17 [SC] 1CB8F79F656BCD71BF9A89694C95665DD06F8126 uid [ unknown] testkey ssb# ed25519 2021-04-17 [E] The imported secret subkey is unusable. Files can be encrypted, but decryption fails with "no secret key". This occurs on GnuPG 2.2.19 and GnuPG 2.2.27. _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users