1

我们有一个用 ActionScript 编写的遗留工具，它使用 AES-CBC 和硬编码的共享密钥对输入进行加密。我正在尝试在 Typescript 中编写相应的解密函数但没有成功。AS3 端使用带有 NullPad 和空（例如长度 0）IV 的 Hurlant as3crypto 库。另外值得注意的是，共享密钥只有 15 个字节而不是 16 个。as3crypto 似乎并不介意这一点，我也尝试过使用 16 字节密钥但没有成功。我的目标是修复 Javascript 中的 aesDecrypt() 函数，以便我可以成功解密 AS3 aesEncrypt() 函数的输出。

下面我有 AS3 中的 encypt（以及工作解密对应物），然后是我在 Typescript 中尝试的解密（和相应的加密）函数。在此示例中，输入“test”在 AS3 中被加密为“ryhkw3BmJ85+qBr0E9bYqw==”，但 Javascript 解密不会产生“test”。

AS3

<?xml version="1.0"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" visible="false">
    <fx:Script><![CDATA[
        import com.hurlant.crypto.Crypto;
        import com.hurlant.crypto.symmetric.ICipher;
        import com.hurlant.crypto.symmetric.IPad;
        import com.hurlant.crypto.symmetric.IVMode;
        import com.hurlant.crypto.symmetric.NullPad;
        import com.hurlant.util.Hex;

        import mx.utils.Base64Decoder;
        import mx.utils.Base64Encoder;

        static var KEY:String = "vI^diTubIwH]Gag";

        internal static function aesEncrypt(decoded:String):String
        {
            var pad:IPad = new NullPad();
            var mode:ICipher = Crypto.getCipher("aes-cbc", Hex.toArray(Hex.fromString(KEY)), pad);
            pad.setBlockSize(mode.getBlockSize());

            var iv:ByteArray = new ByteArray();
            if (mode is IVMode) {
                (mode as IVMode).IV = iv;
            }

            var encoder:Base64Encoder = new Base64Encoder();
            var ba:ByteArray = Hex.toArray(Hex.fromString(decoded));
            mode.encrypt(ba);
            encoder.reset();
            encoder.encodeBytes(ba);
            return encoder.toString();
        }

        internal static function aesDecrypt(encoded:String):String
        {
            var pad:IPad = new NullPad();
            var mode:ICipher = Crypto.getCipher("aes-cbc", Hex.toArray(Hex.fromString(KEY)), pad);
            pad.setBlockSize(mode.getBlockSize());

            var iv:ByteArray = new ByteArray();
            if (mode is IVMode) {
                (mode as IVMode).IV = iv;
            }
            var decoder:Base64Decoder = new Base64Decoder();
            decoder.reset();
            decoder.decode(encoded);
            var ba:ByteArray = decoder.toByteArray();
            mode.decrypt(ba);
            return Hex.toString(Hex.fromArray(ba));
        }

        trace(aesEncrypt('test'));
        trace(aesDecrypt('ryhkw3BmJ85+qBr0E9bYqw=='));
        ]]></fx:Script>
</s:Application>

节点.js

let crypto = require('crypto');

function aesEncrypt(cleartext:string, cipherType:string = 'AES', keyBitLength:number = 128, mode:string = 'CBC', cryptkey:string = 'vI^diTubIwH]Gag') {
  const algorithm = `${cipherType.toLowerCase()}-${keyBitLength}-${mode.toLowerCase()}`;
  const blockSize = keyBitLength / 8;
  const key = Buffer.from(cryptkey);
  const paddedKey = nullPad(key, blockSize);
  const iv = Buffer.alloc(blockSize, 0);
  const cipher = crypto.createCipheriv(algorithm, paddedKey, iv);
  cipher.setAutoPadding(false);
  const encodedInputBuffer = Buffer.from(cleartext, 'utf8');
  const encodedInput = encodedInputBuffer.toString('hex');
  const paddedInputBuffer = nullPad(Buffer.from(encodedInput), blockSize);
  const encrypted = Buffer.concat([cipher.update(paddedInputBuffer), cipher.final()])
  return encrypted.toString('base64');
}

function aesDecrypt(encoded:string, cipherType:string = 'AES', keyBitLength:number = 128, mode:string = 'CBC', cryptkey:string = 'vI^diTubIwH]Gag') {
  const algorithm = `${cipherType.toLowerCase()}-${keyBitLength}-${mode.toLowerCase()}`;
  const blockSize = keyBitLength / 8;
  const key = Buffer.from(cryptkey);
  const paddedKey = nullPad(key, blockSize);
  let iv = Buffer.alloc(blockSize, 0);
  const decipher = crypto.createDecipheriv(algorithm, paddedKey, iv);
  decipher.setAutoPadding(false);
  const decodedInput = Buffer.from(encoded, 'base64').toString( 'binary');
  let decrypted = Buffer.concat([decipher.update(decodedInput, 'binary'), decipher.final()]);
  return decrypted.toString().trim();
}

function nullPad(input:Buffer, length:number) {
  const nullPad = Buffer.alloc(length);
  let padLength = length - (input.length % length);
  if (padLength == length) {
    padLength = 0;
  }

  if(padLength > 0) {
    input = Buffer.concat([input, nullPad.slice(0, padLength)]);
  }
  return input;
}

// should output "ryhkw3BmJ85+qBr0E9bYqw=="
console.log("Encrypt 'test'\t\t\t\t>>>\t" + aesEncrypt("test"));

// should output "test"
console.log("Decrypt 'ryhkw3BmJ85+qBr0E9bYqw=='\t>>>\t" + aesDecrypt("ryhkw3BmJ85+qBr0E9bYqw=="));
// working roundtrips
console.log("Decrypt '+3C9rjmO7W7hIQqcJMPgXQ=='\t>>>\t" + Buffer.from(aesDecrypt("+3C9rjmO7W7hIQqcJMPgXQ=="), 'hex').toString());
console.log("Decrypt 'elaKkhcvG75EBFvZwB1KiA=='\t>>>\t" + aesDecrypt("elaKkhcvG75EBFvZwB1KiA=="));

不幸的是，我们无法像我们希望的那样更新 ActionScript 工具的旧代码（尤其是因为空 IV 和空填充都不好，更不用说非标准密钥长度了）。如果有人可以帮助向我展示如何修复 Javascript 端以便能够解密，我将不胜感激。我更喜欢纯 Node-crypto 解决方案，但很高兴使用 CryptoJS 或 Forge（如果两者都可以的话）（我也没有成功使用它们来完成这项任务）。

4

0 回答 0