GPG

• GPG (GNU Privacy Guard) is an open-source implementation of the OpenPGP standard used for encryption, signing, and verifying data
• GPG2 (GNU Privacy Guard 2) is an updated version of GPG (GnuPG) that provides improved cryptographic features, better security, and supports modern encryption algorithms.

gpg --symmetric --cipher-algo AES256 --passphrase-file password.txt --batch secret.txt

gpg --decrypt --passphrase-file password.txt --batch secret.txt.gpg > secret.txt

• --batch: Prevent GPG from prompting for interactive input.