PHP Manual: Encrypt then authenticate with AES-256-GCM

Description

string sodium_crypto_aead_aes256gcm_encrypt(
    #[\SensitiveParameter]string $message,
    string $additional_data,
    string $nonce,
    #[\SensitiveParameter]string $key
)

Encrypt then authenticate with AES-256-GCM. Only available if sodium_crypto_aead_aes256gcm_is_available returns true.

Parameters

message: The plaintext message to encrypt.
additional_data: Additional, authenticated data. This is used in the verification of the authentication tag appended to the ciphertext, but it is not encrypted or stored in the ciphertext.
nonce: A number that must be only used once, per message. 12 bytes long.
key: Encryption key (256-bit).

Return Values

Returns the ciphertext and authentication tag as a string of raw binary bytes. (Format: ciphertext, then tag.)