I'd like to encrypt a file with AES256 and provide my own 32-bytes for the encryption, rather than having GPG derive it from the passphrase.
I could not find such option, but I'm thinking about a possible workaround.
Per this message:
The other use of passphrases is symmetric-only encryption (command -c) but in most use cases the passphrase comes from another application or a database and is not entered manually. In this case I consider it better to use --s2k-mode=0 along with a full entropy passphrase
Is my understanding correct that I could just pass a 256-bit key as the passphrase to GPG and set some options like: --s2k-mode=0 --s2k-count=0 to get as close as possible to the goal of passing my own AES key? (I guess that some transformation still needs to happen so PGP can ensure that the key is in proper format for AES256)
Are there any extra options to make the output key as plain as possible? Are there any security implications of using it like this?