基于js代码实现的sm4加解密算法

以下是基于JavaScript实现的SM4加解密算法代码示例：

// S-Box
var SBox = [
  0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7, 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
  0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3, 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
  0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a, 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
  0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95, 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
  0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba, 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
  0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b, 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
  0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2, 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
  0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52, 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
  0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5, 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
  0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55, 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
  0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60, 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
  0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f, 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
  0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f, 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
  0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd, 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
  0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e, 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
  0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20, 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48
];

// Fixed parameter
var FK = [0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc];
var CK = [
  0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
  0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
  0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
  0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
  0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
  0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
  0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
  0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
];

// Rotate left shift
function rotateLeftShift(x, n) {
  return (x << n) | (x >>> (32 - n));
}

// Byte array to 32-bit integer
function byteArrayToInt(b) {
  return (b[0] << 24) | (b[1] << 16) | (b[2] << 8) | b[3];
}

// 32-bit integer to byte array
function intToByteArray(i) {
  return [i >>> 24, i >>> 16 & 0xff, i >>> 8 & 0xff, i & 0xff];
}

// SM4 key expansion
function keyExpansion(key) {
  var K = new Array(36);
  var rk = new Array(32);
  var k = new Array(4);
  k[0] = byteArrayToInt(key.slice(0, 4));
  k[1] = byteArrayToInt(key.slice(4, 8));
  k[2] = byteArrayToInt(key.slice(8, 12));
  k[3] = byteArrayToInt(key.slice(12, 16));
  for (var i = 0; i < 4; i++) {
    rk[i] = k[i] ^ FK[i];
  }
  for (var i = 0; i < 32; i++) {
    k[0] = rk[i];
    k[1] = rk[i + 1];
    k[2] = rk[i + 2];
    k[3] = rk[i + 3];
    rk[i + 4] = k[0] ^ rotateLeftShift(k[1] ^ k[2] ^ k[3] ^ CK[i], 13);
  }
  for (var i = 0; i < 36; i += 4) {
    K[i] = rk[i];
    K[i + 1] = rk[i + 1];
    K[i + 2] = rk[i + 2];
    K[i + 3] = rk[i + 3];
  }
  return K;
}

// SM4 round function
function roundFunction(X, K) {
  var Y = new Array(4);
  Y[0] = X[0] ^ (rotateLeftShift(X[1], 2) ^ rotateLeftShift(X[1], 10) ^ rotateLeftShift(X[1], 18) ^ rotateLeftShift(X[1], 24)) ^ (X[2] ^ X[3] ^ K[0]);
  Y[1] = X[1] ^ (rotateLeftShift(X[2], 2) ^ rotateLeftShift(X[2], 10) ^ rotateLeftShift(X[2], 18) ^ rotateLeftShift(X[2], 24)) ^ (X[3] ^ X[0] ^ K[1]);
  Y[2] = X[2] ^ (rotateLeftShift(X[3], 2) ^ rotateLeftShift(X[3], 10) ^ rotateLeftShift(X[3], 18) ^ rotateLeftShift(X[3], 24)) ^ (X[0] ^ X[1] ^ K[2]);
  Y[3] = X[3] ^ (rotateLeftShift(X[0], 2) ^ rotateLeftShift(X[0], 10) ^ rotateLeftShift(X[0], 18) ^ rotateLeftShift(X[0], 24)) ^ (X[1] ^ X[2] ^ K[3]);
  return Y;
}

// SM4 encrypt
function encrypt(msg, key) {
  var K = keyExpansion(key);
  var X = new Array(4);
  var Y = new Array(4);
  var B = new Array(16);
  var C = new Array(16);
  var n = msg.length / 16;
  for (var i = 0; i < n; i++) {
    X[0] = byteArrayToInt(msg.slice(i * 16, i * 16 + 4));
    X[1] = byteArrayToInt(msg.slice(i * 16 + 4, i * 16 + 8));
    X[2] = byteArrayToInt(msg.slice(i * 16 + 8, i * 16 + 12));
    X[3] = byteArrayToInt(msg.slice(i * 16 + 12, i * 16 + 16));
    for (var j = 0; j < 32; j++) {
      Y = roundFunction(X, K.slice(j * 4, j * 4 + 4));
      X[0] = Y[0];
      X[1] = Y[1];
      X[2] = Y[2];
      X[3] = Y[3];
    }
    C = intToByteArray(X[0]).concat(intToByteArray(X[1]), intToByteArray(X[2]), intToByteArray(X[3]));
    for (var j = 0; j < 16; j++) {
      B[i * 16 + j] = C[j];
    }
  }
  return B;
}

// SM4 decrypt
function decrypt(msg, key) {
  var K = keyExpansion(key);
  K.reverse();
  var X = new Array(4);
  var Y = new Array(4);
  var B = new Array(16);
  var C = new Array(16);
  var n = msg.length / 16;
  for (var i = 0; i < n; i++) {
    X[0] = byteArrayToInt(msg.slice(i * 16, i * 16 + 4));
    X[1] = byteArrayToInt(msg.slice(i * 16 + 4, i * 16 + 8));
    X[2] = byteArrayToInt(msg.slice(i * 16 + 8, i * 16 + 12));
    X[3] = byteArrayToInt(msg.slice(i * 16 + 12, i * 16 + 16));
    for (var j = 0; j < 32; j++) {
      Y = roundFunction(X, K.slice(j * 4, j * 4 + 4));
      X[0] = Y[0];
      X[1] = Y[1];
      X[2] = Y[2];
      X[3] = Y[3];
    }
    C = intToByteArray(X[0]).concat(intToByteArray(X[1]), intToByteArray(X[2]), intToByteArray(X[3]));
    for (var j = 0; j < 16; j++) {
      B[i * 16 + j] = C[j];
    }
  }
  return B;
}

使用示例：

// Encrypt
var key = [0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10];
var msg = [0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10];
var ciphertext = encrypt(msg, key);
console.log(ciphertext);

// Decrypt
var plaintext = decrypt(ciphertext, key);
console.log(plaintext);