perf：完善加密模块

2023-03-06 23:15:03 +08:00
parent a1a986950d
commit 96f83612a1
5 changed files with 591 additions and 81 deletions
--- a/index.js
+++ b/index.js
@@ -3,7 +3,7 @@ const Storage = require('./src/utils/Storage')
 const HttpUtil = require('./src/https/HttpUtil')

 module.exports = {
-  HttpUtil,
-  Common,
-  Storage,
-}
+    HttpUtil,
+    Common,
+    Storage,
+}
--- a/package.json
+++ b/package.json
@@ -20,7 +20,7 @@
    "@tiesheng:registry": "http://git.kepai365.com/api/v4/projects/417/packages/npm/"
  },
  "dependencies": {
-    "cryptsm2-sm4": "^1.0.1",
+    "base64-js": "1.5.1",
    "umi-request": "1.4.0"
  }
 }
--- a/src/https/HttpUtil.js
+++ b/src/https/HttpUtil.js
@@ -1,71 +1,82 @@
 const {extend} = require('umi-request');
 const Storage = require('../utils/Storage');
 const Common = require('../utils/Common');
+const crypto = require("../utils/Crypto");

 const codeMessage = {
-  200: "服务器成功返回请求的数据。",
-  201: "新建或修改数据成功。",
-  202: "一个请求已经进入后台排队（异步任务）。",
-  204: "删除数据成功。",
-  400: "发出的请求有错误，服务器没有进行新建或修改数据的操作。",
-  401: "用户没有权限（令牌、用户名、密码错误）。",
-  403: "用户得到授权，但是访问是被禁止的。",
-  404: "发出的请求针对的是不存在的记录，服务器没有进行操作。",
-  406: "请求的格式不可得。",
-  410: "请求的资源被永久删除，且不会再得到的。",
-  422: "当创建一个对象时，发生一个验证错误。",
-  500: "服务器发生错误，请检查服务器。",
-  502: "网关错误。",
-  503: "服务不可用，服务器暂时过载或维护。",
-  504: "网关超时。",
+    200: "服务器成功返回请求的数据。",
+    201: "新建或修改数据成功。",
+    202: "一个请求已经进入后台排队（异步任务）。",
+    204: "删除数据成功。",
+    400: "发出的请求有错误，服务器没有进行新建或修改数据的操作。",
+    401: "用户没有权限（令牌、用户名、密码错误）。",
+    403: "用户得到授权，但是访问是被禁止的。",
+    404: "发出的请求针对的是不存在的记录，服务器没有进行操作。",
+    406: "请求的格式不可得。",
+    410: "请求的资源被永久删除，且不会再得到的。",
+    422: "当创建一个对象时，发生一个验证错误。",
+    500: "服务器发生错误，请检查服务器。",
+    502: "网关错误。",
+    503: "服务不可用，服务器暂时过载或维护。",
+    504: "网关超时。",
 };

 /**
 * 异常处理程序
 */
 const errorHandler = (error) => {
-  const {response = {}} = error;
-  let res = {code: -1, message: "参数错误或服务器异常"};
-  if (!Common.isEmpty(res)) {
-    res = {code: response.status, message: codeMessage[response.status] || response.statusText};
-  }
-  return res;
+    const {response = {}} = error;
+    let res = {code: -1, message: "参数错误或服务器异常"};
+    if (!Common.isEmpty(res)) {
+        res = {code: response.status, message: codeMessage[response.status] || response.statusText};
+    }
+    return res;
 };

 /**
 * 配置request请求时的默认参数
 */
 const request = extend({
-  errorHandler, // 默认错误处理
-  credentials: "include", // 默认请求是否带上cookie,
-  requestType: "json", // 表单提交post请求
+    errorHandler, // 默认错误处理
+    credentials: "include", // 默认请求是否带上cookie,
+    requestType: "json", // 表单提交post请求
 });

+
+/**
+ * 请求配置
+ * @type {{encryptBody: boolean}}
+ */
+let httpConfig = {
+    encryptBody: true,
+}
+
+
 /**
 * 通用数据处理
 * @param options
 */
 const dealParamsBody = (options) => {
-  // 存在分页器的时候
-  if (options.params?.pagination) {
-    options.params.length = options.params.pagination.pageSize;
-    options.params.start = options.params.length * (options.params.pagination.current - 1);
-    delete options.params['pagination'];
-  }
+    // 存在分页器的时候
+    if (options.params?.pagination) {
+        options.params.length = options.params.pagination.pageSize;
+        options.params.start = options.params.length * (options.params.pagination.current - 1);
+        delete options.params['pagination'];
+    }

-  // equals 处理
-  if (options.params && options.params.equals) {
-    let ids = [];
-    let equalsObj = options.params.equals;
-    Object.keys(equalsObj).map((key) => {
-      if (!Common.isEmpty(equalsObj[key])) {
-        ids.push(key + '=' + equalsObj[key]);
-      }
-    });
-    options.params.equals = ids.join(',');
-  }
+    // equals 处理
+    if (options.params && options.params.equals) {
+        let ids = [];
+        let equalsObj = options.params.equals;
+        Object.keys(equalsObj).map((key) => {
+            if (!Common.isEmpty(equalsObj[key])) {
+                ids.push(key + '=' + equalsObj[key]);
+            }
+        });
+        options.params.equals = ids.join(',');
+    }

-  return options;
+    return options;
 };

 /**
@@ -75,29 +86,28 @@ const dealParamsBody = (options) => {
 * @returns {Promise<<any>>}
 */
 async function req(url, options) {
-  return new Promise((resolve, reject) => {
-    request(url, {
-      ...dealParamsBody(options),
-      headers: {
-        ...options.headers,
-        token: Storage.getUserToken() || '',
-      },
-    })
-        .then((res) => {
-          if (res.code == 200) {
-            let data = res.data;
-            if (res.encrypt) {
-
-            }
-            resolve(data)
-          } else {
-            reject(res)
-          }
+    return new Promise((resolve, reject) => {
+        request(url, {
+            ...dealParamsBody(options),
+            headers: {
+                ...options.headers, token: Storage.getUserToken() || '',
+            },
        })
-        .catch((err) => {
-          reject({code: err.data.status, message: err.data.error});
-        });
-  });
+            .then((res) => {
+                if (res.code == 200) {
+                    let data = res.data;
+                    if (res.encrypt) {
+                        data = crypto.decrypt(data);
+                    }
+                    resolve(data)
+                } else {
+                    reject(res)
+                }
+            })
+            .catch((err) => {
+                reject({code: err.data.status, message: err.data.error});
+            });
+    });
 }

 /**
@@ -106,7 +116,7 @@ async function req(url, options) {
 * @param params
 */
 async function get(url, params = {}) {
-  return req(url, {method: 'GET', params});
+    return req(url, {method: 'GET', params});
 }

 /**
@@ -115,7 +125,17 @@ async function get(url, params = {}) {
 * @param data
 */
 async function post(url, data = {}) {
-  return req(url, {method: 'POST', data});
+
+    let newData = {}
+    if (httpConfig.encryptBody) {
+        newData.encryptData = crypto.encrypt(JSON.stringify(data));
+    } else {
+        newData = {...data};
+    }
+
+    console.log(newData);
+
+    return req(url, {method: 'POST', data: newData});
 }

 /**
@@ -125,13 +145,22 @@ async function post(url, data = {}) {
 * @returns {Promise<unknown>}
 */
 async function form(url, data = {}) {
-  return req(url, {method: 'POST', data, requestType: 'form'});
+    return req(url, {method: 'POST', data, requestType: 'form'});
+}
+
+/**
+ * 网络请求配置
+ * @param obj
+ */
+function setConfig(obj) {
+    httpConfig = obj;
 }


 module.exports = {
-  req,
-  get,
-  post,
-  form,
+    req,
+    get,
+    post,
+    form,
+    setConfig,
 }
--- a/src/utils/Crypto.js
+++ b/src/utils/Crypto.js
@@ -1,8 +1,34 @@
-const {SM4} = require('cryptsm2-sm4');
+const base64js = require("base64-js");
+const keyBase64 = "WmdUzPJXbngVNiaSsQrihg==";
+const SM4 = require("./SM4");
+
+class Crypto {
+
+    constructor() {
+        this.sm4 = new SM4({
+            keyBuffer: base64js.toByteArray(keyBase64),
+            mode: "ecb",
+            cipherType: 'base64'
+        })
+    }


-// let decryptByDataKey = app.decryptByDataKey("LT7Wd2k7tk0EXuGtUAyz0Q==", );
+    /**
+     * 加密数据
+     * @param content
+     */
+    encrypt(content) {
+        return this.sm4.encrypt(content);
+    }

-const sm4 = new SM4("WmdUzPJXbngVNiaSsQrihg==");
-sm4.
-console.log(sm4);
+
+    /**
+     * 解密数据
+     * @param base64
+     */
+    decrypt(base64) {
+        return this.sm4.decrypt(base64);
+    }
+}
+
+module.exports = new Crypto();
--- a/src/utils/SM4.js
+++ b/src/utils/SM4.js
@@ -0,0 +1,455 @@
+const base64js = require('base64-js')
+
+const UINT8_BLOCK = 16
+
+const Sbox = Uint8Array.from([
+    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 = Uint32Array.from([
+    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 = Uint32Array.from([
+    0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
+])
+
+class Crypt {
+    /**
+     * Converts a JS string to an UTF-8 uint8array.
+     *
+     * @static
+     * @param {String} str 16-bit unicode string.
+     * @return {Uint8Array} UTF-8 Uint8Array.
+     * @memberof Crypt
+     */
+    static stringToArrayBufferInUtf8 (str) {
+        // if not browser env, then require node.js's util. otherwise just use window's
+        const TextEncoder = (typeof window === 'undefined') ? require('util').TextEncoder : window.TextEncoder
+        // always utf-8
+        let encoder = new TextEncoder()
+        return encoder.encode(str)
+    }
+
+    /**
+     * Converts an UTF-8 uint8array to a JS string.
+     *
+     * @static
+     * @param {Uint8Array} strBuffer UTF-8 Uint8Array.
+     * @return {String} 16-bit unicode string.
+     * @memberof Crypt
+     */
+    static utf8ArrayBufferToString (strBuffer) {
+        // if not browser env, then require node.js's util. otherwise just use window's
+        const TextDecoder = (typeof window === 'undefined') ? require('util').TextDecoder : window.TextDecoder
+        let decoder = new TextDecoder('utf-8')
+        return decoder.decode(strBuffer)
+    }
+
+    /**
+     * crypt a utf8 byteArray to base64 string
+     *
+     * @static
+     * @param {Uint8Array} strBuffer UTF-8 Uint8Array.
+     * @returns {String} base64 str
+     * @memberof Crypt
+     */
+    static arrayBufferToBase64 (strBuffer) {
+        return base64js.fromByteArray(strBuffer)
+    }
+
+    /**
+     * crypt base64 stringa to utf8 byteArray
+     *
+     * @static
+     * @param {String} base64 str
+     * @returns {Uint8Array} strBuffer UTF-8 Uint8Array.
+     * @memberof Crypt
+     */
+    static base64ToArrayBuffer (base64) {
+        return base64js.toByteArray(base64)
+    }
+}
+
+class SM4 {
+    /**
+     * Creates an instance of SM4.
+     * @param {Object} config
+     * @memberof SM4
+     */
+    constructor(config) {
+        if (config.keyBuffer.length !== 16) {
+            throw new Error('key should be a 16 bytes string')
+        }
+        /**
+         * key should be 16 bytes string
+         * @member {Uint8Array} key
+         */
+        this.key = config.keyBuffer
+        /**
+         * iv also should be 16 bytes string
+         * @member {Uint8Array} iv
+         */
+        let ivBuffer = new Uint8Array(0)
+        if (config.iv !== undefined && config.iv !== null) {
+            // need iv
+            ivBuffer = Crypt.stringToArrayBufferInUtf8(config.iv)
+            if (ivBuffer.length !== 16) {
+                throw new Error('iv should be a 16 bytes string')
+            }
+        }
+        this.iv = ivBuffer
+        /**
+         * sm4's encrypt mode
+         * @member {Enum} mode
+         */
+        this.mode = 'cbc'
+        if (['cbc', 'ecb'].indexOf(config.mode) >= 0) {
+            // set encrypt mode. default is cbc
+            this.mode = config.mode
+        }
+        /**
+         * sm4's cipher data type
+         * @member {Enum} outType
+         */
+        this.cipherType = 'base64'
+        if (['base64', 'text'].indexOf(config.outType) >= 0) {
+            // set encrypt mode. default is cbc
+            this.cipherType = config.outType
+        }
+        /**
+         * sm4's encrypt round key array
+         * @member {Uint32Array} encryptRoundKeys
+         */
+        this.encryptRoundKeys = new Uint32Array(32)
+        // spawn 32 round keys
+        this.spawnEncryptRoundKeys()
+
+        /**
+         * sm4's decrypt round key array
+         * @member {Uint32Array} encryptRoundKeys
+         */
+        this.decryptRoundKeys = Uint32Array.from(this.encryptRoundKeys)
+        this.decryptRoundKeys.reverse()
+    }
+
+    /**
+     * general sm4 encrypt/decrypt algorithm for a 16 bytes block using roundKey
+     *
+     * @param {Uint32Array} blockData
+     * @param {Uint32Array} roundKeys
+     * @return {Uint32Array} return a 16 bytes cipher block
+     * @memberof SM4
+     */
+    doBlockCrypt(blockData, roundKeys) {
+        let xBlock = new Uint32Array(36)
+        xBlock.set(blockData, 0)
+        // loop to process 32 rounds crypt
+        for (let i = 0; i < 32; i++) {
+            xBlock[i + 4] = xBlock[i] ^ this.tTransform1(xBlock[i + 1] ^ xBlock[i + 2] ^ xBlock[i + 3] ^ roundKeys[i])
+        }
+        let yBlock = new Uint32Array(4)
+        // reverse last 4 xBlock member
+        yBlock[0] = xBlock[35]
+        yBlock[1] = xBlock[34]
+        yBlock[2] = xBlock[33]
+        yBlock[3] = xBlock[32]
+        return yBlock
+    }
+
+    /**
+     * spawn round key array for encrypt. reverse this key array when decrypt.
+     * every round key's length is 32 bytes.
+     * there are 32 round keys.
+     * @return {Uint32Array}
+     * @memberof SM4
+     */
+    spawnEncryptRoundKeys() {
+        // extract mk in key
+        let mk = new Uint32Array(4)
+        mk[0] = this.key[0] << 24 | this.key[1] << 16 | this.key[2] << 8 | this.key[3]
+        mk[1] = this.key[4] << 24 | this.key[5] << 16 | this.key[6] << 8 | this.key[7]
+        mk[2] = this.key[8] << 24 | this.key[9] << 16 | this.key[10] << 8 | this.key[11]
+        mk[3] = this.key[12] << 24 | this.key[13] << 16 | this.key[14] << 8 | this.key[15]
+        // calculate the K array
+        let k = new Uint32Array(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]
+        // loop to spawn 32 round keys
+        for (let i = 0; i < 32; i++) {
+            k[i + 4] = k[i] ^ this.tTransform2(k[i + 1] ^ k[i + 2] ^ k[i + 3] ^ CK[i])
+            this.encryptRoundKeys[i] = k[i + 4]
+        }
+    }
+
+    /**
+     * left rotate x by y bits
+     *
+     * @param {*} x
+     * @param {Number} y
+     * @returns
+     * @memberof SM4
+     */
+    rotateLeft(x, y) {
+        return x << y | x >>> (32 - y)
+    }
+
+    /**
+     * L transform function for encrypt
+     *
+     * @param {Uint32Number} b
+     * @returns {Uint32Number}
+     * @memberof SM4
+     */
+    linearTransform1(b) {
+        return b ^ this.rotateLeft(b, 2) ^ this.rotateLeft(b, 10) ^ this.rotateLeft(b, 18) ^ this.rotateLeft(b, 24)
+    }
+
+    /**
+     * L' transform function for key expand
+     *
+     * @param {Uint32Number} b
+     * @returns {Uint32Number}
+     * @memberof SM4
+     */
+    linearTransform2(b) {
+        return b ^ this.rotateLeft(b, 13) ^ this.rotateLeft(b, 23)
+    }
+
+    /**
+     * τ transform function
+     *
+     * @param {Uint32Number} a
+     * @returns {Uint32Number}
+     * @memberof SM4
+     */
+    tauTransform(a) {
+        return Sbox[a >>> 24 & 0xff] << 24 | Sbox[a >>> 16 & 0xff] << 16 | Sbox[a >>> 8 & 0xff] << 8 | Sbox[a & 0xff]
+    }
+
+    /**
+     * mix replacement T transform for encrypt
+     *
+     * @param {Uint32Number} z
+     * @returns {Uint32Number}
+     * @memberof SM4
+     */
+    tTransform1(z) {
+        let b = this.tauTransform(z)
+        let c = this.linearTransform1(b)
+        return c
+    }
+
+    /**
+     * mix replacement T transform for key expand
+     *
+     * @param {Uint32Number} z
+     * @returns {Uint32Number}
+     * @memberof SM4
+     */
+    tTransform2(z) {
+        let b = this.tauTransform(z)
+        let c = this.linearTransform2(b)
+        return c
+    }
+
+    /**
+     * padding the array length to multiple of BLOCK
+     *
+     * @param {ByteArray} originalBuffer
+     * @returns {ByteArray}
+     * @memberof SM4
+     */
+    padding(originalBuffer) {
+        if (originalBuffer === null) {
+            return null
+        }
+        let paddingLength = UINT8_BLOCK - originalBuffer.length % UINT8_BLOCK
+        let paddedBuffer = new Uint8Array(originalBuffer.length + paddingLength)
+        paddedBuffer.set(originalBuffer, 0)
+        paddedBuffer.fill(paddingLength, originalBuffer.length)
+        return paddedBuffer
+    }
+
+    /**
+     * depadding the byte array to its original length
+     *
+     * @param {ByteArray} paddedBuffer
+     * @returns {ByteArray}
+     * @memberof SM4
+     */
+    dePadding(paddedBuffer) {
+        if (paddedBuffer === null) {
+            return null
+        }
+        let paddingLength = paddedBuffer[paddedBuffer.length - 1]
+        let originalBuffer = paddedBuffer.slice(0, paddedBuffer.length - paddingLength)
+        return originalBuffer
+    }
+
+    /**
+     * exctract uint32 array block from uint8 array
+     *
+     * @param {Uint8Array} uint8Array
+     * @param {Number} baseIndex
+     * @returns {Uint32Array}
+     * @memberof SM4
+     */
+    uint8ToUint32Block(uint8Array, baseIndex = 0) {
+        let block = new Uint32Array(4)// make Uint8Array to Uint32Array block
+        block[0] = uint8Array[baseIndex] << 24 | uint8Array[baseIndex + 1] << 16 | uint8Array[baseIndex + 2] << 8 | uint8Array[baseIndex + 3]
+        block[1] = uint8Array[baseIndex + 4] << 24 | uint8Array[baseIndex + 5] << 16 | uint8Array[baseIndex + 6] << 8 | uint8Array[baseIndex + 7]
+        block[2] = uint8Array[baseIndex + 8] << 24 | uint8Array[baseIndex + 9] << 16 | uint8Array[baseIndex + 10] << 8 | uint8Array[baseIndex + 11]
+        block[3] = uint8Array[baseIndex + 12] << 24 | uint8Array[baseIndex + 13] << 16 | uint8Array[baseIndex + 14] << 8 | uint8Array[baseIndex + 15]
+        return block
+    }
+
+    /**
+     * encrypt the string plaintext
+     *
+     * @param {String} plaintext
+     * @memberof SM4
+     * @return {String} ciphertext
+     */
+    encrypt(plaintext) {
+        let plainByteArray = Crypt.stringToArrayBufferInUtf8(plaintext)
+        let padded = this.padding(plainByteArray)
+        let blockTimes = padded.length / UINT8_BLOCK
+        let outArray = new Uint8Array(padded.length)
+        if (this.mode === 'cbc') {
+            // CBC mode
+            if (this.iv === null || this.iv.length !== 16) {
+                throw new Error('iv error')
+            }
+            // init chain with iv (transform to uint32 block)
+            let chainBlock = this.uint8ToUint32Block(this.iv)
+            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 = this.uint8ToUint32Block(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 = this.doBlockCrypt(chainBlock, this.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
+                }
+            }
+        } else {
+            // this will be ECB mode
+            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 = this.uint8ToUint32Block(padded, roundIndex)
+                let cipherBlock = this.doBlockCrypt(block, this.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 (this.cipherType === 'base64') {
+            return Crypt.arrayBufferToBase64(outArray)
+        } else {
+            // text
+            return Crypt.utf8ArrayBufferToString(outArray)
+        }
+    }
+
+    /**
+     * decrypt the string ciphertext
+     *
+     * @param {String} ciphertext
+     * @memberof SM4
+     */
+    decrypt(ciphertext) {
+        // get cipher byte array
+        let cipherByteArray = new Uint8Array()
+        if (this.cipherType === 'base64') {
+            // cipher is base64 string
+            cipherByteArray = Crypt.base64ToArrayBuffer(ciphertext)
+        } else {
+            // cipher is text
+            cipherByteArray = Crypt.stringToArrayBufferInUtf8(ciphertext)
+        }
+        let blockTimes = cipherByteArray.length / UINT8_BLOCK
+        let outArray = new Uint8Array(cipherByteArray.length)
+        // decrypt the ciphertext by block
+        if (this.mode === 'cbc') {
+            // todo CBC mode
+            if (this.iv === null || this.iv.length !== 16) {
+                throw new Error('iv error')
+            }
+            // init chain with iv (transform to uint32 block)
+            let chainBlock = this.uint8ToUint32Block(this.iv)
+            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 = this.uint8ToUint32Block(cipherByteArray, roundIndex)
+                // reverse the round keys to decrypt
+                let plainBlockBeforeXor = this.doBlockCrypt(block, this.decryptRoundKeys)
+                // xor the chain block
+                let plainBlock = new Uint32Array(4)
+                plainBlock[0] = chainBlock[0] ^ plainBlockBeforeXor[0]
+                plainBlock[1] = chainBlock[1] ^ plainBlockBeforeXor[1]
+                plainBlock[2] = chainBlock[2] ^ plainBlockBeforeXor[2]
+                plainBlock[3] = 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
+                }
+            }
+        } else {
+            // ECB mode
+            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 = this.uint8ToUint32Block(cipherByteArray, roundIndex)
+                // reverse the round keys to decrypt
+                let plainBlock = this.doBlockCrypt(block, this.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 = this.dePadding(outArray)
+        // transform data to utf8 string
+        return Crypt.utf8ArrayBufferToString(depaddedPlaintext)
+    }
+}
+
+module.exports = SM4