javascript实现国密SM4加密解密

从gm-crypt拷贝，可直接在浏览器中执行，低版本的浏览器需要先用babel编译
另外需要引入base64js

更新：修复中文加解密乱码

const UINT8_BLOCK = 16;
const 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
];
const 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
];
const FK = [
    0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
];

/**
 * 将字符串转为Unicode数组
 * @example "1234" => [49, 50, 51, 52];
 * @param {String} str 要转换的字符串
 * @returns {Number[]} 转换后的数组
 */
const stringToArray = (str) => {
    if(!/string/gi.test(Object.prototype.toString.call(str))){
        str = JSON.stringify(str);
    }
    return unescape(encodeURIComponent(str)).split("").map(val => val.charCodeAt());
}

const rotateLeft = (x, y) => {
    return x << y | x >>> (32 - y);
}

const tauTransform = (a) => {
    return Sbox[a >>> 24 & 0xff] << 24 | Sbox[a >>> 16 & 0xff] << 16 | Sbox[a >>> 8 & 0xff] << 8 | Sbox[a & 0xff];
}

const tTransform1 = (z) => {
    let b = tauTransform(z);
    let c = b ^ rotateLeft(b, 2) ^ rotateLeft(b, 10) ^ rotateLeft(b, 18) ^ rotateLeft(b, 24);
    return c
}

const tTransform2 = (z) => {
    let b = tauTransform(z);
    let c = b ^ rotateLeft(b, 13) ^ rotateLeft(b, 23);
    return c
}

const EncryptRoundKeys = (key) => {
    const keys = [];
    const mk = [
        key[0] << 24 | key[1] << 16 | key[2] << 8 | key[3],
        key[4] << 24 | key[5] << 16 | key[6] << 8 | key[7],
        key[8] << 24 | key[9] << 16 | key[10] << 8 | key[11],
        key[12] << 24 | key[13] << 16 | key[14] << 8 | key[15]
    ];

    let k = new Array(36);
    k[0] = mk[0] ^ FK[0];
    k[1] = mk[1] ^ FK[1];
    k[2] = mk[2] ^ FK[2];
    k[3] = mk[3] ^ FK[3];

    for (let i = 0; i < 32; i++) {
        k[i + 4] = k[i] ^ tTransform2(k[i + 1] ^ k[i + 2] ^ k[i + 3] ^ CK[i]);
        keys[i] = k[i + 4];
    }

    return keys;
}

const getChainBlock = (arr, baseIndex = 0) => {
    let block = [
        arr[baseIndex] << 24 | arr[baseIndex + 1] << 16 | arr[baseIndex + 2] << 8 | arr[baseIndex + 3],
        arr[baseIndex + 4] << 24 | arr[baseIndex + 5] << 16 | arr[baseIndex + 6] << 8 | arr[baseIndex + 7],
        arr[baseIndex + 8] << 24 | arr[baseIndex + 9] << 16 | arr[baseIndex + 10] << 8 | arr[baseIndex + 11],
        arr[baseIndex + 12] << 24 | arr[baseIndex + 13] << 16 | arr[baseIndex + 14] << 8 | arr[baseIndex + 15]
    ];
    return block;
}

const doBlockCrypt = (blockData, roundKeys) => {
    let xBlock = new Array(36);
    blockData.forEach((val, index) => xBlock[index] = val);
    // loop to process 32 rounds crypt
    for (let i = 0; i < 32; i++) {
        xBlock[i + 4] = xBlock[i] ^ tTransform1(xBlock[i + 1] ^ xBlock[i + 2] ^ xBlock[i + 3] ^ roundKeys[i]);
    }
    let yBlock = [xBlock[35], xBlock[34], xBlock[33], xBlock[32]];
    return yBlock;
}

const padding = (originalBuffer) => {
    if (originalBuffer === null) {
        return null;
    }
    let paddingLength = UINT8_BLOCK - originalBuffer.length % UINT8_BLOCK;
    let paddedBuffer = new Array(originalBuffer.length + paddingLength);

    originalBuffer.forEach((val, index) => paddedBuffer[index] = val);
    paddedBuffer.fill(paddingLength, originalBuffer.length);
    return paddedBuffer;
}


const dePadding = (paddedBuffer) => {
    if (paddedBuffer === null) {
        return null;
    }
    let paddingLength = paddedBuffer[paddedBuffer.length - 1];
    let originalBuffer = paddedBuffer.slice(0, paddedBuffer.length - paddingLength);
    return originalBuffer;
}

const check = (name, str) => {
    if(!str || str.length != 16){
        console.error(`${name} should be a 16 bytes string.`);
        return false;
    }
    return true;
}

/**
 * CBC加密模式
 * @example encrypt_cbc("1234", "1234567890123456", "1234567890123456") => "K++iI4IhSGMnEJZT/jv1ow=="
 * @param {any} plaintext 要加密的数据
 * @param {String} key 
 * @param {String} iv 
 * @param {String} mode base64 | "text"
 * @returns {String} 加密后的字符串
 */
const encrypt_cbc = (plaintext, key, iv, mode = "base64") => {
    if(!check("iv", iv) && !check("key", key)){return;}

    let encryptRoundKeys = EncryptRoundKeys(stringToArray(key));
    let plainByteArray = stringToArray(plaintext);
    let padded = padding(plainByteArray);
    let blockTimes = padded.length / UINT8_BLOCK;
    let outArray = [];
    // init chain with iv (transform to uint32 block)
    let chainBlock = getChainBlock(stringToArray(iv));
    console.log(padded, blockTimes, encryptRoundKeys, chainBlock);
    for (let i = 0; i < blockTimes; i++) {
        // extract the 16 bytes block data for this round to encrypt
        let roundIndex = i * UINT8_BLOCK;
        let block = getChainBlock(padded, roundIndex);
        // xor the chain block
        chainBlock[0] = chainBlock[0] ^ block[0];
        chainBlock[1] = chainBlock[1] ^ block[1];
        chainBlock[2] = chainBlock[2] ^ block[2];
        chainBlock[3] = chainBlock[3] ^ block[3];
        // use chain block to crypt
        let cipherBlock = doBlockCrypt(chainBlock, encryptRoundKeys);
        // make the cipher block be part of next chain block
        chainBlock = cipherBlock;
        for (let l = 0; l < UINT8_BLOCK; l++) {
            outArray[roundIndex + l] = cipherBlock[parseInt(l / 4)] >> ((3 - l) % 4 * 8) & 0xff;
        }
    }

    // cipher array to string
    if (mode === 'base64') {
        return base64js.fromByteArray(outArray);
    } else {
        // text
        return decodeURIComponent(escape(String.fromCharCode(...outArray)));
    }
}
/**
 * ECB加密模式
 * @example encrypt_cbc("1234", "1234567890123456") => "woPrxebr8Xvyo1qG8QxAUA=="
 * @param {any} plaintext 要加密的数据
 * @param {String} key 
 * @param {String} iv 
 * @param {String} mode base64 | "text"
 * @returns {String} 加密后的字符串
 */
const encrypt_ecb = (plaintext, key, mode = "base64") => {
    if(!check("iv", iv)){return;}

    let encryptRoundKeys = EncryptRoundKeys(stringToArray(key));
    let plainByteArray = stringToArray(plaintext);
    let padded = padding(plainByteArray);
    let blockTimes = padded.length / UINT8_BLOCK;
    let outArray = [];
    // CBC mode
    // init chain with iv (transform to uint32 block)
    for (let i = 0; i < blockTimes; i++) {
        // extract the 16 bytes block data for this round to encrypt
        let roundIndex = i * UINT8_BLOCK;
        let block = getChainBlock(padded, roundIndex);
        let cipherBlock = doBlockCrypt(block, encryptRoundKeys);
        for (let l = 0; l < UINT8_BLOCK; l++) {
            outArray[roundIndex + l] = cipherBlock[parseInt(l / 4)] >> ((3 - l) % 4 * 8) & 0xff;
        }
    }

    // cipher array to string
    if (mode === 'base64') {
        return base64js.fromByteArray(outArray);
    } else {
        // text
        return decodeURIComponent(escape(String.fromCharCode(...outArray)));
    }
}
/**
 * CBC解密模式
 * @example decrypt_cbc("K++iI4IhSGMnEJZT/jv1ow==", "1234567890123456", "1234567890123456") => "1234"
 * @param {any} plaintext 要解密的数据
 * @param {String} key 
 * @param {String} iv 
 * @param {String} mode base64 | "text"
 * @returns {String} 解密后的字符串
 */
const decrypt_cbc = (ciphertext, key, iv, mode = "base64") => {
    if(!check("iv", iv) && !check("key", key)){return;}
    // get cipher byte array
    let cipherByteArray = null;
    let decryptRoundKeys = EncryptRoundKeys(stringToArray(key)).reverse();
    if (mode === 'base64') {
        // cipher is base64 string
        cipherByteArray = base64js.toByteArray(ciphertext);
    } else {
        // cipher is text
        cipherByteArray = stringToArray(ciphertext);
    }

    let blockTimes = cipherByteArray.length / UINT8_BLOCK;
    let outArray = [];

    // init chain with iv (transform to uint32 block)
    let chainBlock = getChainBlock(stringToArray(iv));
    console.log(cipherByteArray, decryptRoundKeys, chainBlock)
    for (let i = 0; i < blockTimes; i++) {
        // extract the 16 bytes block data for this round to encrypt
        let roundIndex = i * UINT8_BLOCK;
        // make Uint8Array to Uint32Array block
        let block = getChainBlock(cipherByteArray, roundIndex);
        // reverse the round keys to decrypt
        let plainBlockBeforeXor = doBlockCrypt(block, decryptRoundKeys);
        // xor the chain block
        let plainBlock = [
            chainBlock[0] ^ plainBlockBeforeXor[0],
            chainBlock[1] ^ plainBlockBeforeXor[1],
            chainBlock[2] ^ plainBlockBeforeXor[2],
            chainBlock[3] ^ plainBlockBeforeXor[3]
        ];
        // make the cipher block be part of next chain block
        chainBlock = block;
        for (let l = 0; l < UINT8_BLOCK; l++) {
            outArray[roundIndex + l] = plainBlock[parseInt(l / 4)] >> ((3 - l) % 4 * 8) & 0xff;
        }
    }
    // depadding the decrypted data
    let depaddedPlaintext = dePadding(outArray);
    // transform data to utf8 string
    return decodeURIComponent(escape(String.fromCharCode(...depaddedPlaintext)));
}
/**
 * ECB解密模式
 * @example decrypt_ecb("woPrxebr8Xvyo1qG8QxAUA==", "1234567890123456") => "1234"
 * @param {any} plaintext 要解密的数据
 * @param {String} key 
 * @param {String} iv 
 * @param {String} mode base64 | "text"
 * @returns {String} 解密后的字符串
 */
const decrypt_ecb = (ciphertext, key, mode = "base64") => {
    if(!check("iv", iv)){return;}
    // get cipher byte array
    let decryptRoundKeys = EncryptRoundKeys(stringToArray(key)).reverse();
    let cipherByteArray = null;
    if (mode === 'base64') {
        // cipher is base64 string
        cipherByteArray = base64js.toByteArray(ciphertext);
    } else {
        // cipher is text
        cipherByteArray = stringToArray(ciphertext);
    }
    let blockTimes = cipherByteArray.length / UINT8_BLOCK;
    let outArray = [];

    for (let i = 0; i < blockTimes; i++) {
        // extract the 16 bytes block data for this round to encrypt
        let roundIndex = i * UINT8_BLOCK;
        // make Uint8Array to Uint32Array block
        let block = getChainBlock(cipherByteArray, roundIndex);
        // reverse the round keys to decrypt
        let plainBlock = doBlockCrypt(block, decryptRoundKeys);
        for (let l = 0; l < UINT8_BLOCK; l++) {
            outArray[roundIndex + l] = plainBlock[parseInt(l / 4)] >> ((3 - l) % 4 * 8) & 0xff;
        }
    }

    // depadding the decrypted data
    let depaddedPlaintext = dePadding(outArray);
    // transform data to utf8 string
    return decodeURIComponent(escape(String.fromCharCode(...depaddedPlaintext)));
}