AES-GCM
also: GCM, Galois/Counter Mode, AES-256-GCM, AES-128-GCM
AES-GCM is a modern encryption cipher that combines AES (Advanced Encryption Standard) with Galois/Counter Mode, providing both data confidentiality and authentication in a single operation.
AES-GCM stands for Advanced Encryption Standard with Galois/Counter Mode. It encrypts data using AES and simultaneously generates an authentication tag that verifies the data hasn't been tampered with. This authenticated encryption is more secure than using encryption and authentication separately.
The GCM mode operates as a stream cipher, processing data block-by-block and producing ciphertext plus an authentication tag. Unlike older modes like CBC, GCM can verify both confidentiality and integrity in one pass, making it efficient for modern applications.
Example: When using openssl with AES-256-GCM, the command might be: openssl enc -aes-256-gcm -in plaintext.txt -out encrypted.bin. This encrypts the file and generates an authentication tag, ensuring that only the intended recipient can decrypt it and verify it hasn't been modified.
AES-GCM is widely used in TLS/SSL encryption, disk encryption, and secure messaging protocols because it's fast, secure, and prevents both eavesdropping and tampering attacks.