Authenticated encryption apparatus with initialization-vector misuse resistance and method therefor

Abstract

A module has a processor for executing an encryption process to encrypt a message to a cipher-text with authentication. The encryption process includes generating a tag from a secret message authentication code (MAC) key, a nonce, a message, and optionally an additional data using a Poly1305 function, generating a pseudorandom initialization vector (IV) from a secret encryption key and the tag using a first encryption function, and generating a cipher-text from the secret encryption key, the generated IV, and the message using a second encryption function. The module or a similar module may execute a corresponding decryption process to decrypt the cipher-text to a decrypted message and verify the authenticity of the cipher-text. At least one of the first and second encryption functions may be an Advanced Encryption Standard (AES) encryption function such as an AES-CTR encryption function, an AES-like encryption function, and/or other suitable encryption functions.