A computer-implemented authenticated encryption method for converting a plaintext message into a ciphertext message, said method comprising: dividing said plaintext message into at least two working blocks (504a, 504b, 504c), each respective working block of said at least two working blocks having a mathematical relationship to said plaintext message; for each respective working block of said at least two working blocks: computing a working block ciphertext (506a, 506b, 506c) as a function of said respective working block (504a, 504b, 504c), a deterministic working block initialization vector (518a, 518b, 518c), and a deterministic working block encryption key; and computing a message authentication tag (508a, 508b, 508c) as a function of: a deterministic working block message authentication key, the working block ciphertext (506a, 506b, 506c) computed for said respective working block, said deterministic working block initialization vector (518a, 518b, 518c) used to compute said working block ciphertext for said respective working block, said deterministic working block initialization vector providing a distinct input to said computing of said message authentication tag (508a, 508b, 508c), and an indication corresponding to said mathematical relationship of said respective working block to said plaintext message; computing a global message authentication tag as a function of the message authentication tag (508a, 508b, 508c) computed for each respective working block of said at least two working blocks and the global message authentication key; and wherein said ciphertext message comprises the working block ciphertext (506a, 506b, 506c) computed for each respective working block of said working blocks (504a, 504b, 504c) and said global message authentication tag. dividing said plaintext message into at least two working blocks (504a, 504b, 504c), each respective working block of said at least two working blocks having a mathematical relationship to said plaintext message; for each respective working block of said at least two working blocks: computing a working block ciphertext (506a, 506b, 506c) as a function of said respective working block (504a, 504b, 504c), a deterministic working block initialization vector (518a, 518b, 518c), and a deterministic working block encryption key; and computing a message authentication tag (508a, 508b, 508c) as a function of: a deterministic working block message authentication key, the working block ciphertext (506a, 506b, 506c) computed for said respective working block, said deterministic working block initialization vector (518a, 518b, 518c) used to compute said working block ciphertext for said respective working block, said deterministic working block initialization vector providing a distinct input to said computing of said message authentication tag (508a, 508b, 508c), and an indication corresponding to said mathematical relationship of said respective working block to said plaintext message; computing a working block ciphertext (506a, 506b, 506c) as a function of said respective working block (504a, 504b, 504c), a deterministic working block initialization vector (518a, 518b, 518c), and a deterministic working block encryption key; and computing a message authentication tag (508a, 508b, 508c) as a function of: a deterministic working block message authentication key, the working block ciphertext (506a, 506b, 506c) computed for said respective working block, said deterministic working block initialization vector (518a, 518b, 518c) used to compute said working block ciphertext for said respective working block, said deterministic working block initialization vector providing a distinct input to said computing of said message authentication tag (508a, 508b, 508c), and an indication corresponding to said mathematical relationship of said respective working block to said plaintext message; computing a global message authentication tag as a function of the message authentication tag (508a, 508b, 508c) computed for each respective working block of said at least two working blocks and the global message authentication key; and wherein said ciphertext message comprises the working block ciphertext (506a, 506b, 506c) computed for each respective working block of said working blocks (504a, 504b, 504c) and said global message authentication tag.