Function cryptBlock

aes.js:27–61

(M, keySchedule, SUB_MIX, SBOX, nRounds)

}

function cryptBlock (M, keySchedule, SUB_MIX, SBOX, nRounds) {
  var SUB_MIX0 = SUB_MIX[0]
  var SUB_MIX1 = SUB_MIX[1]
  var SUB_MIX2 = SUB_MIX[2]
  var SUB_MIX3 = SUB_MIX[3]

  var s0 = M[0] ^ keySchedule[0]
  var s1 = M[1] ^ keySchedule[1]
  var s2 = M[2] ^ keySchedule[2]
  var s3 = M[3] ^ keySchedule[3]
  var t0, t1, t2, t3
  var ksRow = 4

  for (var round = 1; round < nRounds; round++) {
    t0 = SUB_MIX0[s0 >>> 24] ^ SUB_MIX1[(s1 >>> 16) & 0xff] ^ SUB_MIX2[(s2 >>> 8) & 0xff] ^ SUB_MIX3[s3 & 0xff] ^ keySchedule[ksRow++]
    t1 = SUB_MIX0[s1 >>> 24] ^ SUB_MIX1[(s2 >>> 16) & 0xff] ^ SUB_MIX2[(s3 >>> 8) & 0xff] ^ SUB_MIX3[s0 & 0xff] ^ keySchedule[ksRow++]
    t2 = SUB_MIX0[s2 >>> 24] ^ SUB_MIX1[(s3 >>> 16) & 0xff] ^ SUB_MIX2[(s0 >>> 8) & 0xff] ^ SUB_MIX3[s1 & 0xff] ^ keySchedule[ksRow++]
    t3 = SUB_MIX0[s3 >>> 24] ^ SUB_MIX1[(s0 >>> 16) & 0xff] ^ SUB_MIX2[(s1 >>> 8) & 0xff] ^ SUB_MIX3[s2 & 0xff] ^ keySchedule[ksRow++]
    s0 = t0
    s1 = t1
    s2 = t2
    s3 = t3
  }

  t0 = ((SBOX[s0 >>> 24] << 24) | (SBOX[(s1 >>> 16) & 0xff] << 16) | (SBOX[(s2 >>> 8) & 0xff] << 8) | SBOX[s3 & 0xff]) ^ keySchedule[ksRow++]
  t1 = ((SBOX[s1 >>> 24] << 24) | (SBOX[(s2 >>> 16) & 0xff] << 16) | (SBOX[(s3 >>> 8) & 0xff] << 8) | SBOX[s0 & 0xff]) ^ keySchedule[ksRow++]
  t2 = ((SBOX[s2 >>> 24] << 24) | (SBOX[(s3 >>> 16) & 0xff] << 16) | (SBOX[(s0 >>> 8) & 0xff] << 8) | SBOX[s1 & 0xff]) ^ keySchedule[ksRow++]
  t3 = ((SBOX[s3 >>> 24] << 24) | (SBOX[(s0 >>> 16) & 0xff] << 16) | (SBOX[(s1 >>> 8) & 0xff] << 8) | SBOX[s2 & 0xff]) ^ keySchedule[ksRow++]
  t0 = t0 >>> 0
  t1 = t1 >>> 0
  t2 = t2 >>> 0
  t3 = t3 >>> 0

  return [t0, t1, t2, t3]
}

// AES constants
var RCON = [0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36]