A computer-implemented authenticated encryption method for converting a plaintext message into a ciphertext message. The method includes dividing the plaintext message into at least two working blocks, each working block having a mathematical relationship to the plaintext message. For each working block, a working block ciphertext is computed as a function of such working block, a deterministic working block initialization vector, and a deterministic working block encryption key. For each working block, a message authentication tag is computed as a function of a deterministic working block message authentication key and at least one of (a) the working block ciphertext computed for such working block and an indication corresponding to the mathematical relationship of such working block to the plaintext message and (b) such working block. The method further includes computing a global message authentication tag as a function of the message authentication tag computed for each working block and a global message authentication key. The ciphertext message comprises the working block ciphertext computed for each working block and the global message authentication tag.