微信小程序使用 aes 加密

提供两种库的实现方式。

使用 crypto-js 实现

注：只能使用 3.x 版本， 4.x 版本不支持微信小程序。

小程序构建后依赖体积大约为 218kb

const message = CryptoJS.enc.Utf8.parse(data);
const key = CryptoJS.enc.Utf8.parse(encryptKey);
const iv = CryptoJS.enc.Utf8.parse(encryptIV);
const cryptoStr = CryptoJS.AES.encrypt(message, key, {
  iv,
});
// 以下分别是以base64以及hex格式输出
const base64Str = CryptoJS.format.OpenSSL.stringify(cryptoStr); // 或者直接 cryptoStr.toString()
const hexStr = CryptoJS.format.Hex.stringify(cryptoStr);

使用 aes-js 实现

小程序构建后依赖体积大约为 64kb

const message = aesjs.padding.pkcs7.pad(aesjs.utils.utf8.toBytes(data));
const key = aesjs.utils.utf8.toBytes(encryptKey);
const iv = aesjs.utils.utf8.toBytes(encryptIV);
const aesCbc = new aesjs.ModeOfOperation.cbc(key, iv);
const encryptedBytes = aesCbc.encrypt(message);
// 以下分别是以base64以及hex格式输出
const hexStr = aesjs.utils.hex.fromBytes(encryptedBytes);
const base64Str = arrayBufferToBase64(encryptedBytes);

aes-js 自带的工具函数只支持输出 hex 格式，若需要输出 base64 格式，需要自行转换

var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
exports.weBtoa = function (string) {
  string = String(string);
  var bitmap,
    a,
    b,
    c,
    result = "",
    i = 0,
    rest = string.length % 3;
  for (; i < string.length; ) {
    if (
      (a = string.charCodeAt(i++)) > 255 ||
      (b = string.charCodeAt(i++)) > 255 ||
      (c = string.charCodeAt(i++)) > 255
    )
      throw new TypeError(
        "Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the Latin1 range."
      );
    bitmap = (a << 16) | (b << 8) | c;
    result +=
      b64.charAt((bitmap >> 18) & 63) +
      b64.charAt((bitmap >> 12) & 63) +
      b64.charAt((bitmap >> 6) & 63) +
      b64.charAt(bitmap & 63);
  }
  return rest ? result.slice(0, rest - 3) + "===".substring(rest) : result;
};
function arrayBufferToBase64(bytes) {
  let binary = "";
  var len = bytes.byteLength;
  for (var i = 0; i < len; i++) {
    binary += String.fromCharCode(bytes[i]);
  }
  return weBtoa(binary);
}

补充：小程序加解密工具函数

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
var b64re =
  /^(?:[A-Za-z\d+\/]{4})*?(?:[A-Za-z\d+\/]{2}(?:==)?|[A-Za-z\d+\/]{3}=?)?$/;
exports.weBtoa = function (string) {
  string = String(string);
  var bitmap,
    a,
    b,
    c,
    result = "",
    i = 0,
    rest = string.length % 3;
  for (; i < string.length; ) {
    if (
      (a = string.charCodeAt(i++)) > 255 ||
      (b = string.charCodeAt(i++)) > 255 ||
      (c = string.charCodeAt(i++)) > 255
    )
      throw new TypeError(
        "Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the Latin1 range."
      );
    bitmap = (a << 16) | (b << 8) | c;
    result +=
      b64.charAt((bitmap >> 18) & 63) +
      b64.charAt((bitmap >> 12) & 63) +
      b64.charAt((bitmap >> 6) & 63) +
      b64.charAt(bitmap & 63);
  }
  return rest ? result.slice(0, rest - 3) + "===".substring(rest) : result;
};
exports.weAtob = function (string) {
  string = String(string).replace(/[\t\n\f\r ]+/g, "");
  if (!b64re.test(string))
    throw new TypeError(
      "Failed to execute 'atob' on 'Window': The string to be decoded is not correctly encoded."
    );
  string += "==".slice(2 - (string.length & 3));
  var bitmap,
    result = "",
    r1,
    r2,
    i = 0;
  for (; i < string.length; ) {
    bitmap =
      (b64.indexOf(string.charAt(i++)) << 18) |
      (b64.indexOf(string.charAt(i++)) << 12) |
      ((r1 = b64.indexOf(string.charAt(i++))) << 6) |
      (r2 = b64.indexOf(string.charAt(i++)));
    result +=
      r1 === 64
        ? String.fromCharCode((bitmap >> 16) & 255)
        : r2 === 64
        ? String.fromCharCode((bitmap >> 16) & 255, (bitmap >> 8) & 255)
        : String.fromCharCode(
            (bitmap >> 16) & 255,
            (bitmap >> 8) & 255,
            bitmap & 255
          );
  }
  return result;
};
function b64DecodeUnicode(str) {
  return decodeURIComponent(
    exports.weAtob(str).replace(/(.)/g, function (p) {
      var code = p.charCodeAt(0).toString(16).toUpperCase();
      if (code.length < 2) {
        code = "0" + code;
      }
      return "%" + code;
    })
  );
}
function base64_url_decode(str) {
  var output = str.replace(/-/g, "+").replace(/_/g, "/");
  switch (output.length % 4) {
    case 0:
      break;
    case 2:
      output += "==";
      break;
    case 3:
      output += "=";
      break;
    default:
      throw "Illegal base64url string!";
  }
  try {
    return b64DecodeUnicode(output);
  } catch (err) {
    return exports.weAtob(output);
  }
}
function weappJwtDecode(token, options) {
  if (typeof token !== "string") {
    throw "Invalid token specified";
  }
  options = options || {};
  var pos = options.header === true ? 0 : 1;
  try {
    return JSON.parse(base64_url_decode(token.split(".")[pos]));
  } catch (e) {
    throw "Invalid token specified: " + e.message;
  }
}
exports.default = weappJwtDecode;