Private key required for backup encryption?

[tgranqvist]

It seems that a PGP private key is required to get asymmetric encryption to work. Setting only DB01_ENCRYPT_PUBLIC_KEY causes an error and leaves the produced backup unencrypted. Why? The recipients public key should be enough for encryption, yes? What's the private key needed for? I don't see any attempt to sign the output, which would need a private key.

I believe the issue comes from row 1350 in install/assets/functions/10-db-backup:

elif [ -z "${backup_job_encrypt_passphrase}" ] && [ -n "${backup_job_encrypt_public_key}" ] && [ -n "${backup_job_encrypt_private_key}" ]; then