Galois/Counter Mode (GCM)

wikipedia:Galois/Counter Mode

aws ec2 export-client-vpn-client-configuration
.../...
cipher AES-256-GCM
.../...

/var/log/openvpn.log
Thu Jan 13 11:51:17 2022 xx.193.213.1:52709 Data Channel: using negotiated cipher 'AES-256-GCM'

\conninfo 

See also

• Public-key cryptography: RSA, DSA, ECDSA, EdDSA (Ed25519), AES, RSA Conference, hash, pkeyutl, Signature, key length, Easyrsa, OAEP, Ron Rivest, Adi Shamir, Leonard Adleman
• Cipher, Supported Ciphers, AES, DES, Galois/Counter Mode (GCM), CBC, ChaCha20