本文介绍了c＃BouncyCastle异常：pad块损坏的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我一直在使用由@nerdybeardo撰写的加密和解密的代码。但是，我得到错误垫块损坏，当尝试解密。
I've been using the code that was posted here to encrypt and decrypt, written by @nerdybeardo. However, I'm getting the error "pad block corrupted" when trying to decrypt.
Encryptor 类看起来像这样，然后实现加密然后MAC：
The Encryptor class looks like this, which implements encrypt then MAC:
/// <summary>
/// Encrypt/decrypt + HMAC using BouncyCastle (C# Java port)
/// </summary>
/// <typeparam name="TBlockCipher">The type of the block cipher.</typeparam>
/// <typeparam name="TDigest">The type of the digest.</typeparam>
/// <see cref="http://stackoverflow.com/a/13511671/119624"/>
public sealed class Encryptor<TBlockCipher, TDigest>
where TBlockCipher : IBlockCipher, new()
where TDigest : IDigest, new()
{
private readonly Encoding encoding;
private readonly byte[] key;
private IBlockCipher blockCipher;
private BufferedBlockCipher cipher;
private HMac mac;
/// <summary>
/// Initializes a new instance of the <see cref="Encryptor{TBlockCipher, TDigest}"/> class.
/// </summary>
/// <param name="encoding">The encoding.</param>
/// <param name="key">The key.</param>
/// <param name="macKey">The mac key.</param>
public Encryptor(Encoding encoding, byte[] key, byte[] macKey)
{
this.encoding = encoding;
this.key = key;
this.Init(key, macKey, new Pkcs7Padding());
}
/// <summary>
/// Initializes a new instance of the <see cref="Encryptor{TBlockCipher, TDigest}"/> class.
/// </summary>
/// <param name="encoding">The encoding.</param>
/// <param name="key">The key.</param>
/// <param name="macKey">The mac key.</param>
/// <param name="padding">The padding.</param>
public Encryptor(Encoding encoding, byte[] key, byte[] macKey, IBlockCipherPadding padding)
{
this.encoding = encoding;
this.key = key;
this.Init(key, macKey, padding);
}
/// <summary>
/// Encrypts the specified plain.
/// </summary>
/// <param name="plain">The plain.</param>
/// <returns></returns>
public string Encrypt(string plain)
{
return Convert.ToBase64String(EncryptBytes(plain));
}
/// <summary>
/// Encrypts the bytes.
/// </summary>
/// <param name="plain">The plain.</param>
/// <returns></returns>
public byte[] EncryptBytes(string plain)
{
byte[] input = this.encoding.GetBytes(plain);
var iv = this.GenerateInitializationVector();
var cipher = this.BouncyCastleCrypto(true, input, new ParametersWithIV(new KeyParameter(key), iv));
byte[] message = CombineArrays(iv, cipher);
this.mac.Reset();
this.mac.BlockUpdate(message, 0, message.Length);
var digest = new byte[this.mac.GetUnderlyingDigest().GetDigestSize()];
this.mac.DoFinal(digest, 0);
var result = CombineArrays(digest, message);
return result;
}
/// <summary>
/// Decrypts the bytes.
/// </summary>
/// <param name="bytes">The bytes.</param>
/// <returns></returns>
/// <exception cref="CryptoException"></exception>
public byte[] DecryptBytes(byte[] bytes)
{
// split the digest into component parts
var digest = new byte[this.mac.GetUnderlyingDigest().GetDigestSize()];
var message = new byte[bytes.Length - digest.Length];
var iv = new byte[this.blockCipher.GetBlockSize()];
var cipher = new byte[message.Length - iv.Length];
Buffer.BlockCopy(bytes, 0, digest, 0, digest.Length);
Buffer.BlockCopy(bytes, digest.Length, message, 0, message.Length);
if (!IsValidHMac(digest, message))
{
throw new CryptoException();
}
Buffer.BlockCopy(message, 0, iv, 0, iv.Length);
Buffer.BlockCopy(message, iv.Length, cipher, 0, cipher.Length);
byte[] result = this.BouncyCastleCrypto(false, cipher, new ParametersWithIV(new KeyParameter(key), iv));
return result;
}
/// <summary>
/// Decrypts the specified bytes.
/// </summary>
/// <param name="bytes">The bytes.</param>
/// <returns></returns>
public string Decrypt(byte[] bytes)
{
return this.encoding.GetString(DecryptBytes(bytes));
}
/// <summary>
/// Decrypts the specified cipher.
/// </summary>
/// <param name="cipher">The cipher.</param>
/// <returns></returns>
public string Decrypt(string cipher)
{
return this.Decrypt(Convert.FromBase64String(cipher));
}
/// <summary>
/// Combines the arrays.
/// </summary>
/// <param name="source1">The source1.</param>
/// <param name="source2">The source2.</param>
/// <returns></returns>
private static byte[] CombineArrays(byte[] source1, byte[] source2)
{
var result = new byte[source1.Length + source2.Length];
Buffer.BlockCopy(source1, 0, result, 0, source1.Length);
Buffer.BlockCopy(source2, 0, result, source1.Length, source2.Length);
return result;
}
/// <summary>
/// Ares the equal.
/// </summary>
/// <param name="digest">The digest.</param>
/// <param name="computed">The computed.</param>
/// <returns></returns>
private static bool AreEqual(byte[] digest, byte[] computed)
{
if (digest.Length != computed.Length)
{
return false;
}
var result = 0;
for (var i = 0; i < digest.Length; i++)
{
result |= digest[i] ^ computed[i];
}
return result == 0;
}
/// <summary>
/// Initializes the specified key.
/// </summary>
/// <param name="key">The key.</param>
/// <param name="macKey">The mac key.</param>
/// <param name="padding">The padding.</param>
private void Init(byte[] key, byte[] macKey, IBlockCipherPadding padding)
{
this.blockCipher = new CbcBlockCipher(new TBlockCipher());
this.cipher = new PaddedBufferedBlockCipher(this.blockCipher, padding);
this.mac = new HMac(new TDigest());
this.mac.Init(new KeyParameter(macKey));
}
/// <summary>
/// Determines whether [is valid h mac] [the specified digest].
/// </summary>
/// <param name="digest">The digest.</param>
/// <param name="message">The message.</param>
/// <returns></returns>
private bool IsValidHMac(byte[] digest, byte[] message)
{
this.mac.Reset();
this.mac.BlockUpdate(message, 0, message.Length);
var computed = new byte[this.mac.GetUnderlyingDigest().GetDigestSize()];
this.mac.DoFinal(computed, 0);
return AreEqual(digest, computed);
}
/// <summary>
/// Bouncy Castle Cryptography.
/// </summary>
/// <param name="forEncrypt">if set to <c>true</c> [for encrypt].</param>
/// <param name="input">The input.</param>
/// <param name="parameters">The parameters.</param>
/// <returns></returns>
private byte[] BouncyCastleCrypto(bool forEncrypt, byte[] input, ICipherParameters parameters)
{
try
{
cipher.Init(forEncrypt, parameters);
return this.cipher.DoFinal(input);
}
catch (CryptoException)
{
throw;
}
}
/// <summary>
/// Generates the initialization vector.
/// </summary>
/// <returns></returns>
private byte[] GenerateInitializationVector()
{
using (var provider = new RNGCryptoServiceProvider())
{
// 1st block
var result = new byte[this.blockCipher.GetBlockSize()];
provider.GetBytes(result);
return result;
}
}
}
我有一个简单的包装器AES引擎。它看起来像这样：
I have a simple wrapper for the AES engine. It looks like this:
public class AesSha256Encryptor
{
private readonly Encryptor<AesEngine, Sha256Digest> provider;
/// <summary>
/// Initializes a new instance of the <see cref="AesSha256Encryptor"/> class.
/// </summary>
/// <param name="key">The key.</param>
/// <param name="hmacKey">The HMAC key.</param>
public AesSha256Encryptor(byte[] key, byte[] hmacKey)
{
provider = new Encryptor<AesEngine, Sha256Digest>(Encoding.UTF8, key, hmacKey);
}
/// <summary>
/// Encrypts the specified plain.
/// </summary>
/// <param name="plain">The plain.</param>
/// <returns></returns>
public string Encrypt(string plain)
{
return provider.Encrypt(plain);
}
/// <summary>
/// Decrypts the specified cipher.
/// </summary>
/// <param name="cipher">The cipher.</param>
/// <returns></returns>
public string Decrypt(string cipher)
{
return provider.Decrypt(cipher);
}
}
我希望能有一个不同的盐数据库行，所以我有一个关键管理器，工作原理如下：
I wanted to be able to have a different salt per database row, so I have a key manager that works like this:
public static class EncryptionKeyManager
{
/// <summary>
/// The salt length limit
/// </summary>
private const int SaltLengthLimit = 32;
/// <summary>
/// Gets the key record.
/// </summary>
/// <returns></returns>
public static KeyRecord GetKeyRecord()
{
// get the shared passphrasefrom appsettings
var sharedPassphrase = GetSharedPassphrase();
// get the client passphrase from config db to sign
var clientPassphrase = GetClientPassphrase();
// generate secure random salt
var salt = GetSalt();
// get both the encryption key and hmac key
// these will be used for Encrypt-then-Mac
var key = GetKeyFromPassphrase(sharedPassphrase, salt);
var hmacKey = GetKeyFromPassphrase(clientPassphrase, salt);
return new KeyRecord
{
SharedKey = key,
HmacKey = hmacKey,
Salt = salt
};
}
/// <summary>
/// Gets the client salt.
/// </summary>
/// <returns></returns>
private static string GetClientPassphrase()
{
var settingsService = ServiceLocator.Current.GetInstance<ISettingService>();
return settingsService.GetSetting(ConstantConfigSettings.EncryptionSettings.ClientPassphrase, defaultValue: "<removed>");
}
/// <summary>
/// Gets the shared passphrase.
/// </summary>
/// <returns></returns>
private static string GetSharedPassphrase()
{
return ConfigurationManager.AppSettings[ConstantConfigSettings.EncryptionSettings.SharedPassphrase] ?? "<removed>";
}
/// <summary>
/// Gets the key from passphrase.
/// </summary>
/// <param name="passphrase">The passphrase.</param>
/// <param name="salt">The salt.</param>
/// <returns></returns>
private static byte[] GetKeyFromPassphrase(string passphrase, string salt)
{
var saltArray = Encoding.UTF8.GetBytes(salt);
var rfcKey = new Rfc2898DeriveBytes(passphrase, saltArray, 10000);
return rfcKey.GetBytes(32); // for a 256-bit key (32*8=128)
}
/// <summary>
/// Gets the salt from a secure random generator..
/// </summary>
/// <param name="maximumSaltLength">Maximum length of the salt.</param>
/// <returns></returns>
private static string GetSalt(int maximumSaltLength = SaltLengthLimit)
{
var salt = new byte[maximumSaltLength];
using (var random = new RNGCryptoServiceProvider())
{
random.GetNonZeroBytes(salt);
}
return Convert.ToBase64String(salt);
}
}
p>
It all gets used like this to encrypt:
// get key and salt from
var keyRecord = EncryptionKeyManager.GetKeyRecord();
var aesSha256Encryptor = new AesSha256Encryptor(keyRecord.SharedKey, keyRecord.HmacKey);
// now encrypt and store, include salt
entity.AccountNumber = aesSha256Encryptor.Encrypt(accountNumber);
entity.SortCode = aesSha256Encryptor.Encrypt(sortCode);
entity.Salt = keyRecord.Salt;
当我要解密时，我执行以下操作：
When I want to decrypt, I do the following:
public static class KeyManager
{
/// <summary>
/// Gets the key from passphrase.
/// </summary>
/// <param name="passphrase">The passphrase.</param>
/// <param name="salt">The salt.</param>
/// <returns>A byte array.</returns>
public static byte[] GetKeyFromPassphrase(string passphrase, string salt)
{
var saltArray = Encoding.UTF8.GetBytes(salt);
var rfcKey = new Rfc2898DeriveBytes(passphrase, saltArray, 10000);
return rfcKey.GetBytes(32); // for a 256-bit key (32*8=128)
}
}
var passphraseKey = KeyManager.GetKeyFromPassphrase(this.Passphrase, this.Salt);
var hmacKey = KeyManager.GetKeyFromPassphrase(this.ClientPassphrase, this.Salt);
var aesSha256Encryptor = new AesSha256Encryptor(passphraseKey, hmacKey);
var plaintext = aesSha256Encryptor.Decrypt(this.CipherText);
这是一个SAAS应用程序。我的基本想法是有一个密码短语是SAAS应用程序的核心，用于加密/解密，但也有一个特定的客户端密码短语用于MAC。其原因是在端点之间传播密钥（一个在数据库中，一个在配置设置中）。盐被保存到数据库，以便它可以用于使用相同的盐进行解密。
This is for a SAAS application. My basic idea was to have a passphrase that is core to the SAAS application that is used to encrypt/decrypt, but also have a specific client passphrase that is used to MAC. The reason for this was to spread the keys between endpoints (one in a database and one in a config setting). The salt gets saved to the database so that it can be used to decrypt using the same salt.
任何人都可以看到我做错了什么？为什么我得到垫块错误？
Can anyone see what I am doing wrong? Why am I getting the pad block error?
FYI：密码短语是马电池订书机正确风格，所以他们有连字符。我不知道，如果这是一个红鲱鱼虽然。
FYI: The passphrases are of the XKCD variety "horse-battery-stapler-correct" style, so they have hyphens in. I'm not sure if that is a red herring though.
我也不知道每行是否需要独特的盐，还是我只能硬编码盐？是多余的吗？
I'm also not sure if the unique salt per row is required, or whether I could just hard code the salt? Is that overkill?
更新
对于发现此问题的任何人，错误仅仅是我认为使用的密码是不正确的。填充错误是结果。
UpdateFor anyone who finds this, the error was simply that the passphrase that I thought was being used was incorrect. The padding error was the result.
推荐答案
不清楚什么代码确切地导致你的问题（我的意思是没有最小的例子我可以只是运行，看看什么是错误），但我建立了一个示例，根据您的代码正确解密，没有错误，所以你可以看看它，可能会发现你的错误。
我创建 EncryptionKeyManager.GetSharedPassphrase（） public，并返回固定字符串 horse-battery-stapler-correct 。我使 EncryptionKeyManager.GetClientPassphrase（）也公开，并返回固定的 horse-battery 。
It is not clear what code exactly causes your problem (I mean there is no minimal example I could just run and see what is wrong), but I built an example which decrypts correctly without errors, based on your code, so you can look at it and probably spot your error.I made EncryptionKeyManager.GetSharedPassphrase() public, and it returns fixed string horse-battery-stapler-correct. I made EncryptionKeyManager.GetClientPassphrase() also public and it returns fixed horse-battery.
class Program {
static void Main(string[] args) {
// get key and salt from
var keyRecord = EncryptionKeyManager.GetKeyRecord();
var aesSha256Encryptor = new AesSha256Encryptor(keyRecord.SharedKey, keyRecord.HmacKey);
string targetData = "4343423343";
var encrypted = aesSha256Encryptor.Encrypt(targetData);
var salt = keyRecord.Salt;
var decrypted = Decrypt(encrypted, salt);
Debug.Assert(targetData == decrypted);
Console.WriteLine(decrypted);
Console.ReadKey();
}
private static string Decrypt(string data, string salt) {
var passphraseKey = KeyManager.GetKeyFromPassphrase(EncryptionKeyManager.GetSharedPassphrase(), salt);
var hmacKey = KeyManager.GetKeyFromPassphrase(EncryptionKeyManager.GetClientPassphrase(), salt);
var aesSha256Encryptor = new AesSha256Encryptor(passphraseKey, hmacKey);
var plaintext = aesSha256Encryptor.Decrypt(data);
return plaintext;
}
}
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