NewCMAC(b *aes.Block) *CMAC { c := &CMAC{b: *b} c.deriveSubkeys() return c } func (c *CMAC) deriveSubkeys() { aes.EncryptBlockInternal(&c.b, c.k1[:], c.k1[:]) msb := shiftLeft(&c.k1) c.k1[len(c.k1)-1] ^= msb * 0b10000111 c.k2 = c.k1 msb = shiftLeft(&c.k2) c.k2[len(c.k2)-1] ^= msb * 0b10000111 } func (c *CMAC) MAC(m []byte) [aes.BlockSize]byte { fips140.RecordApproved() _ = c.b // Hoist the nil check out of the loop. var x [aes.BlockSize]byte if len(m) == 0 { // Special-cased as a single empty partial...