java - C#.net 到 Java-使用带密码的 AES 加密和解密

Question

我试图在 Java 中重现以下加密/解密算法，但我找不到多种方法的替代方案，例如 Rfc2898DeriveBytes() 和 RijndaelManaged()。我该怎么做呢？

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;

namespace CryptingTest
{   
    public static class StringCipher
    {
        // This constant is used to determine the keysize of the encryption algorithm in bits.
        // We divide this by 8 within the code below to get the equivalent number of bytes.
        private const int Keysize = 128;

        // This constant determines the number of iterations for the password bytes generation function.
        private const int DerivationIterations = 1000;

        public static string Encrypt(string plainText, string passPhrase)
        {
            // Salt and IV is randomly generated each time, but is preprended to encrypted cipher text
            // so that the same Salt and IV values can be used when decrypting.  
            var saltStringBytes = Generate128BitsOfRandomEntropy();
            var ivStringBytes = Generate128BitsOfRandomEntropy();
            var plainTextBytes = Encoding.UTF8.GetBytes(plainText);
            using (var password = new Rfc2898DeriveBytes(passPhrase, saltStringBytes, DerivationIterations))
            {
                var keyBytes = password.GetBytes(Keysize / 8);
                using (var symmetricKey = new RijndaelManaged())
                {
                    symmetricKey.BlockSize = 128;
                    symmetricKey.Mode = CipherMode.CBC;
                    symmetricKey.Padding = PaddingMode.PKCS7;
                    using (var encryptor = symmetricKey.CreateEncryptor(keyBytes, ivStringBytes))
                    {
                        using (var memoryStream = new MemoryStream())
                        {
                            using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
                            {
                                cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
                                cryptoStream.FlushFinalBlock();
                                // Create the final bytes as a concatenation of the random salt bytes, the random iv bytes and the cipher bytes.
                                var cipherTextBytes = saltStringBytes;
                                cipherTextBytes = cipherTextBytes.Concat(ivStringBytes).ToArray();
                                cipherTextBytes = cipherTextBytes.Concat(memoryStream.ToArray()).ToArray();
                                memoryStream.Close();
                                cryptoStream.Close();
                                return Convert.ToBase64String(cipherTextBytes);
                            }
                        }
                    }
                }
            }
        }

        public static string Decrypt(string cipherText, string passPhrase)
        {
            // Get the complete stream of bytes that represent:
            // [32 bytes of Salt] + [16 bytes of IV] + [n bytes of CipherText]
            var cipherTextBytesWithSaltAndIv = Convert.FromBase64String(cipherText);
            // Get the saltbytes by extracting the first 16 bytes from the supplied cipherText bytes.
            var saltStringBytes = cipherTextBytesWithSaltAndIv.Take(Keysize / 8).ToArray();
            // Get the IV bytes by extracting the next 16 bytes from the supplied cipherText bytes.
            var ivStringBytes = cipherTextBytesWithSaltAndIv.Skip(Keysize / 8).Take(Keysize / 8).ToArray();
            // Get the actual cipher text bytes by removing the first 64 bytes from the cipherText string.
            var cipherTextBytes = cipherTextBytesWithSaltAndIv.Skip((Keysize / 8) * 2).Take(cipherTextBytesWithSaltAndIv.Length - ((Keysize / 8) * 2)).ToArray();

            using (var password = new Rfc2898DeriveBytes(passPhrase, saltStringBytes, DerivationIterations))
            {
                var keyBytes = password.GetBytes(Keysize / 8);
                using (var symmetricKey = new RijndaelManaged())
                {
                    symmetricKey.BlockSize = 128;
                    symmetricKey.Mode = CipherMode.CBC;
                    symmetricKey.Padding = PaddingMode.PKCS7;
                    using (var decryptor = symmetricKey.CreateDecryptor(keyBytes, ivStringBytes))
                    {
                        using (var memoryStream = new MemoryStream(cipherTextBytes))
                        {
                            using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
                            {
                                var plainTextBytes = new byte[cipherTextBytes.Length];
                                var decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
                                memoryStream.Close();
                                cryptoStream.Close();
                                return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
                            }
                        }
                    }
                }
            }
        }

        private static byte[] Generate128BitsOfRandomEntropy()
        {
            var randomBytes = new byte[16]; // 16 Bytes will give us 128 bits.
            using (var rngCsp = new RNGCryptoServiceProvider())
            {
                // Fill the array with cryptographically secure random bytes.
                rngCsp.GetBytes(randomBytes);
            }
            return randomBytes;
        }
    }
}

任何帮助将非常感激。
这是我迄今为止尝试过的代码片段，但它仍然关闭:

private static byte[] Generate128BitsOfRandomEntropy()
{
    var randomBytes = new byte[16]; // 16 Bytes will give us 128 bits.
       
    SecureRandom rngCsp = new SecureRandom();
    // Fill the array with cryptographically secure random bytes.
    rngCsp.nextBytes(randomBytes);
        
    return randomBytes;
}
    
public static String encrypt(String plainText, String passPhrase) 
{
    try
    {
        var saltStringBytes = Generate128BitsOfRandomEntropy();
        SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
        PBEKeySpec pbeKeySpec = new PBEKeySpec(passPhrase.toCharArray(), saltStringBytes, 1000, 384);
        Key secretKey = factory.generateSecret(pbeKeySpec);
        byte[] key = new byte[16];
        byte[] iv = new byte[16];
        System.arraycopy(secretKey.getEncoded(), 0, key, 0, 16);
        System.arraycopy(secretKey.getEncoded(), 16, iv, 0, 16);

        SecretKeySpec secret = new SecretKeySpec(key, "AES");
        AlgorithmParameterSpec ivSpec = new IvParameterSpec(iv);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secret, ivSpec);

        return Base64.getEncoder().encodeToString(cipher.doFinal(plainText.getBytes("UTF-8")));
    } 
    catch (Exception e) 
    {
        System.out.println("Error while encrypting: " + e.toString());
    }
    return null;
}

Answer 1

Rfc2898DeriveBytes实现 PBKDF2 和 RijndaelManaged块大小为 128 位的情况下实现了 AES。两者似乎都在 Java 代码中正确应用。
但是，在确定IV和连接方面存在差异:在C#代码中，salt和IV是随机确定的，并在最后与密文连接。
在 Java 代码中，只有盐是随机确定的，IV 是与 key 一起导出的，并且缺少连接。
IE。 encrypt() Java 代码中的方法可以更改如下，以便可以使用 C# 代码进行解密:

import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;
import java.util.Base64;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;

...

byte[] salt = Generate128BitsOfRandomEntropy();
byte[] iv = Generate128BitsOfRandomEntropy();

SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
PBEKeySpec pbeKeySpec = new PBEKeySpec(passPhrase.toCharArray(), salt, 1000, 128);
SecretKey secretKey = factory.generateSecret(pbeKeySpec);
SecretKeySpec secretKeySpec = new SecretKeySpec(secretKey.getEncoded(), "AES");

AlgorithmParameterSpec ivSpec = new IvParameterSpec(iv);
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivSpec);
byte[] ciphertext = cipher.doFinal(plainText.getBytes(StandardCharsets.UTF_8));

byte[] saltIvCiphertext = ByteBuffer.allocate(salt.length + iv.length + ciphertext.length).put(salt).put(iv).put(ciphertext).array();
return Base64.getEncoder().encodeToString(saltIvCiphertext);

请注意，对于 PBKDF2，1000 的迭代计数通常太低。