Disclosed embodiments relate to a unified Advanced Encryption Standard (AES), SMS4, and Camellia (CML) accelerator. In one example, a processor includes fetch circuitry to fetch a cipher instruction specifying an opcode, a datum, and a key, the opcode to specify one of three cryptographic modes and an operation, decode circuitry to decode the fetched cipher instruction, and execution circuitry to respond to the decoded cipher instruction by performing the operation using a selected one of three block ciphers corresponding to the specified cryptographic mode and a unified cipher datapath shared by the three block ciphers, the unified cipher datapath comprising a plurality of hybrid substitution boxes (Sboxes) to perform Galois Field (GF) multiplications and inverse computations, wherein the unified cipher datapath is to implement an eighth-order polynomial isomorphically equivalent to each polynomial used by the three block ciphers by calculating and then combining two fourth-order polynomials.