With OpenSSL, I can select a what type of block cipher to use for encrypting a file.
For example, if I want to encrypt a file with AES256 CBC block cipher mode:
openssl aes-256-cbc -a -salt -pass pass:MYPASSWORD -in secrets.txt -out secrets.txt.enc
In gpg2, I try to encrypt a file with the following:
gpg2 --cipher-algo AES256 -a --no-use-agent --passphrase MYPASSWORD -c secrets.txt
There are two problems I could get some help with:
There is no option to specify what cipher block to use. What if I want AES256 CTR or XTS instead of CBC? What cipher block does
--cipher-algo AES256use and how do I specify something specific?
The command completely fails if I don't enter the passphrase in the gnu password agent (I'm trying to supply the passphrase in the command with
--no-use-agent, for possible automation on a trusted machine):
gpg: WARNING: "--no-use-agent" is an obsolete option - it has no effect
gpg: problem with the agent: Invalid card
gpg: error creating passphrase: Operation cancelled
gpg: symmetric encryption of `secrets.txt' failed: Operation cancelled