Java AES加密无法正确解密

Question

我在下面进行了此测试，我正在尝试验证我的AES加密/解密与压缩/解压缩是否正常工作。我只测试加密/解密和仅压缩/解压缩的测试，我个人知道它们正常工作，但由于某些原因，当我将它们组合起来时，IV在解压缩后被搞砸了。我被困住了，不知道还有什么可以寻找，有人可以提供任何建议或帮助吗？如果我需要发布更多代码，请告诉我。我想我包括了重要的东西。

对于上下文：我要做的是获取一些敏感数据，使用AES加密它，使用RSA公钥加密AES密钥，然后压缩这两个数据，以便通过网络发送它们。然后在另一端我要解压缩数据，使用RSA私钥解密AES密钥，然后使用它来解密数据。如果还有另一种方法可以实现这一目标，那么我就不会把自己写成一切。如果您建议使用图书馆，请仅建议我可以在商业产品中使用的图书馆。

@Test
public void testEncryptionDecryptionProcesses() throws SSHException {

    SSHKey key1 = generateKeyPair();

    UnencryptedData data = new UnencryptedData();
    data.setUserName("hardy");
    data.setHashedPassword("somepassword");
    data.setRequest("eat");
    data.setResponse("");
    data.setTimestamp(new Timestamp(new Date().getTime()).toString());
    data.setPublicKeyMod(key1.getPublicMod().toString());
    data.setPublicKey(key1.getPublicKey().toString());

    byte[] bytes = encryptAndCompress(data, key1);

    assertTrue(bytes != null);
    assertTrue(bytes.length > 0);

    UnencryptedData decryptedData = decompressAndDecrypt(bytes, key1);
    assertEquals(data.getDataForEncryption(), decryptedData.getDataForEncryption());

}

public static byte[] encryptAndCompress(UnencryptedData data, SSHKey sshKey) {

    byte[] results = null;

    try {
        byte[] aesKey = createKeyForAES(AES_BIT_LENGTH);
        //this should use the servers public key so that only the server can decrypt it
        //gather data, get a digest, encrypt the data
        UnencryptedData digestedData = createDigest(data);
        //encrypt it
        EncryptedData toCompress = encryptDataAES(digestedData, aesKey);
        String encryptedAESKey = encryptKey(sshKey, aesKey);
        toCompress.setEncryptedAESKey(encryptedAESKey);
        //compress it
        byte[] compressed = compressString(toCompress.getDataForCompression());
        //return the compressed and encrypted data.
        results = compressed;
    } catch(SSHException e) {

        Log.e("SSHFunctions.encryption", "Unable to run the encryption/compression process on the data");
    } catch (UnsupportedEncodingException e) {

        Log.e("SSHFunctions.encryption", "Charset not supported");
    } 

    return results;
}

public static UnencryptedData decompressAndDecrypt(byte[] data, SSHKey sshKey) {

    UnencryptedData results = null;

    try {
        //take the data and decompress it, should result in encryptedData|encryptedAESKey
        byte[] decompressed = decompressString(data);
        String decompressedStr = new String(decompressed, CHAR_SET);
        String[] decompressedArr = decompressedStr.split(SPLIT_STRING);
        //using the users private key decrypt the data
        byte[] decryptedKey = decryptKey(sshKey, decompressedArr[1]);
        EncryptedData encryptedData = new EncryptedData();
        encryptedData.setAesEncryptedData(decompressedArr[0].getBytes(CHAR_SET));
        encryptedData.setIV(decompressedArr[2].getBytes(CHAR_SET)); //TODO: this doesn't seem to decompress correctly
        //create a digest from the decrypted data and compare it with the digest that was included.
        UnencryptedData decryptedDate = decryptDataAES(encryptedData, decryptedKey);
        if(validDigest(decryptedDate)) {

            results = decryptedDate;
        }
        //if equal return the data, if not equal return null
    } catch(Exception e) {

        Log.e("SSHFunctions.decryption", "Unable to run the uncompress/decrypt process on the data");
    }

    return results;
}

public static byte[] decompressString(byte[] toDecompress) {

    ByteArrayInputStream bis = new ByteArrayInputStream(toDecompress);
    byte[] uncompressed;

    try {

        ByteArrayOutputStream buffer = new ByteArrayOutputStream();
        GZIPInputStream is = new GZIPInputStream(bis);

        byte[] tmp = new byte[256];

        while (true) {

            int r = is.read(tmp);
            if (r < 0) {

                break;
            }
            buffer.write(tmp, 0, r);
        }
        is.close();

        uncompressed = buffer.toByteArray();

        try {
            bis.close();
        } catch (IOException e) {
            ;
        }

        try {
            buffer.close();
        } catch (IOException e) {
            ;
        }
    } catch(IOException e) {

        uncompressed = null;
        Log.e("Zipfunctions.decompress", "Unable to decompress");
    }

    return uncompressed;    
}

public static byte[] compressString(byte[] toCompress) {

    byte[] toCompressBytes = toCompress;
    byte[] compressed;

    ByteArrayOutputStream bos = new ByteArrayOutputStream(toCompressBytes.length);
    try {
        GZIPOutputStream compressor = new GZIPOutputStream(bos);

        compressor.write(toCompressBytes, 0, toCompress.length);
        compressor.close();

        compressed = bos.toByteArray();

        try {
            bos.close();
        } catch(IOException e) {
            ;
        }
    } catch(IOException e) {

        compressed = null;
        Log.e("ZipFunctions.compress", "Unable to compress data");
    }

    return compressed;      
}

Answer 1

您正在尝试实施类似于OpenPGP的加密系统。也就是说，您希望使用对称密钥加密任意数量的数据，并与收件人安全地共享此密钥（以及加密数据）。

因此，我建议您考虑使用Java OpenPGP库provided by the BouncyCastle team。

他们的执照是very permissive。但是，他们的文档很差，因此您需要通过Google的许多示例来了解如何实现目标。

Answer 2

首先，您不应该使用字符串分隔符来分隔字节缓冲区的各个部分。如果您的数据中存在分隔符，则会导致问题。

我建议你阅读TLV structure！

以下是传输数据的简单实现！

class TransportData {
private byte[] iv;
private byte[] aesKey;
private byte[] encryptedData;

public TransportData() {
}

public TransportData(byte[] iv, byte[] aesKey, byte[] encryptedData) {
this.iv = iv;
this.aesKey = aesKey;
this.encryptedData = encryptedData;
}

public byte[] encode() throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(baos);
dos.writeInt(iv.length);
dos.write(iv);
dos.writeInt(aesKey.length);
dos.write(aesKey);
dos.writeInt(encryptedData.length);
dos.write(encryptedData);
dos.close();
return baos.toByteArray();
}

public void decode(byte[] buffer) throws IOException {
ByteArrayInputStream bais = new ByteArrayInputStream(buffer);
DataInputStream dis = new DataInputStream(bais);
iv = new byte[dis.readInt()];
dis.read(iv);
aesKey = new byte[dis.readInt()];
dis.read(aesKey);
encryptedData = new byte[dis.readInt()];
dis.read(encryptedData);
dis.close();
}

public byte[] getAesKey() {
return aesKey;
}
public byte[] getEncryptedData() {
return encryptedData;
}
public byte[] getIv() {
return iv;
}
}