Salt 中的什么导致解密失败
What in the Salt causes it to fail in decryption
下面和 Fiddle 中的代码不是用于生产，而是用于教育目的。我不想修复任何东西，因为我有一个可行的解决方案。但是，我想知道为什么：
var password = "password";
var salt = Encoding.ASCII.GetBytes(password.Length.ToString());
var secret = new PasswordDeriveBytes(password, salt);
当上面的实现后，下面的方法FixedEncryptor将起作用。
// Valid:
public static string FixedEncryptor(string content)
{
var cipher = new RijndaelManaged();
var plain = Encoding.Unicode.GetBytes(content);
var key = new PasswordDeriveBytes(password, salt);
using (var encrypt = cipher.CreateEncryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream())
using (var crypto = new CryptoStream(stream, encrypt, CryptoStreamMode.Write))
{
crypto.Write(plain, 0, plain.Length);
crypto.FlushFinalBlock();
return Convert.ToBase64String(stream.ToArray());
}
}
但是，如果您实施：
var secret = new PasswordDeriveBytes("password",
Encoding.ASCII.GetBytes("password"));
代码会突然产生：
Run-time exception (line 70): Padding is invalid and cannot be
removed.
Stack Trace:
[System.Security.Cryptography.CryptographicException: Padding is
invalid and cannot be removed.] at Crypt.Decryptor(String content):
line 70 at Program.Main(): line 17
如下方法表示：
// Invalid:
public static string Encryptor(string content)
{
var cipher = new RijndaelManaged();
var plain = Encoding.Unicode.GetBytes(content);
var key = new PasswordDeriveBytes("password", Encoding.ASCII.GetBytes("password"));
using (var encrypt = cipher.CreateEncryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream())
using (var crypto = new CryptoStream(stream, encrypt, CryptoStreamMode.Write))
{
crypto.Write(plain, 0, plain.Length);
crypto.FlushFinalBlock();
return Convert.ToBase64String(stream.ToArray());
}
}
那为什么一个能解密成功，而另一个解密不正确，出现上述错误呢？
一个Fiddle的小例子是here.
首先，你生成盐的方法一点都不安全；其次，PasswordDerivedBytes 已弃用，您应该查看其继任者 Rfc2898DeriveBytes.
尝试类似以下的操作 - 请注意，这需要一些 using 语句：System、System.IO、System.Security.Cryptography 和 System.Text。
简单地用Encrypt(PlainText, Password)加密数据并用Decrypt(EncryptedData, Password)再次解密。盐作为前 16 个字节卷入加密数据，并且在每个 encryption/decryption 轮中完全随机。
此代码是我自己的开源密码管理器的一部分。
/*
* Encryption/Decryption, based on AES256 and PBKDF2
*/
public string Encrypt (string plainText, string passPhrase, bool fast_encrypt = false)
{
string result;
using (Rijndael algR = Rijndael.Create ()) {
RNGCryptoServiceProvider rngC = new RNGCryptoServiceProvider ();
byte[] iv = new byte[16];
rngC.GetBytes (iv);
Rfc2898DeriveBytes derived = new Rfc2898DeriveBytes (passPhrase, iv, fast_encrypt ? 10 : 3000);
algR.KeySize = 256;
algR.BlockSize = 128;
algR.Key = derived.GetBytes (32);
algR.IV = iv;
using (MemoryStream memoryStream = new MemoryStream ()) {
memoryStream.Write (iv, 0, 16);
using (CryptoStream cryptoStreamEncrypt = new CryptoStream (memoryStream, algR.CreateEncryptor (algR.Key, algR.IV), CryptoStreamMode.Write)) {
using (StreamWriter streamWriterEncrypt = new StreamWriter (cryptoStreamEncrypt)) {
streamWriterEncrypt.Write (plainText);
}
}
result = Convert.ToBase64String (memoryStream.ToArray ());
}
}
return result;
}
public string Decrypt (string cipherText, string passPhrase, bool fast_decrypt = false)
{
string result;
using (Rijndael algR = Rijndael.Create ()) {
using (MemoryStream memoryStream = new MemoryStream (Convert.FromBase64String (cipherText))) {
byte[] iv = new byte[16];
memoryStream.Read (iv, 0, 16);
Rfc2898DeriveBytes derived = new Rfc2898DeriveBytes (passPhrase, iv, fast_decrypt ? 10 : 3000);
algR.KeySize = 256;
algR.BlockSize = 128;
algR.Key = derived.GetBytes (32);
algR.IV = iv;
using (CryptoStream cryptoStreamDecrypt = new CryptoStream (memoryStream, algR.CreateDecryptor (algR.Key, algR.IV), CryptoStreamMode.Read)) {
using (StreamReader streamReaderDecrypt = new StreamReader (cryptoStreamDecrypt)) {
result = streamReaderDecrypt.ReadToEnd ();
}
}
}
}
return result;
}
根据您发布的代码示例，您的问题来自于您使用了两种不同的盐。
在 FixedEncryptor 中，您使用
的盐
Encoding.ASCII.GetBytes(password.Length.ToString());
编码为等于 { 56 } 的字节数组，这是因为 Length returns 8 然后在 returns 上调用 ToString()您将其转换为 ascii 值 56 的字符串“8”。
在 Encryptor 中，您使用
的盐
Encoding.ASCII.GetBytes("password")
编码为字节数组等于{ 112, 97, 115, 115, 119, 111, 114, 100}，即字符"p"、"a"、"s"、[=46=的ascii值]、"w"、"o"、"r" 和 "d"。
您 运行 遇到的问题是您只尝试在解密函数中使用 { 56 }，所以您的问题归结为 您的加密函数和解密函数使用两种不同的盐.
如果我制作一个新的 Decrypter 以使用与 Encryptor 相同的盐和密码，然后制作一个单独的 FixedDecryptor 以匹配 FixedEncryptor 所有内容的盐会很好
public class Program
{
public static void Main()
{
var message = "Hello World!";
var fixedCipherText = Crypt.FixedEncryptor(message);
var cipherText = Crypt.Encryptor(message);
Console.WriteLine(cipherText);
Console.WriteLine(fixedCipherText);
var plainText = Crypt.Decryptor(cipherText);
var fixedPlainText = Crypt.FixedDecryptor(fixedCipherText);
Console.WriteLine(plainText);
Console.WriteLine(fixedPlainText);
}
}
public static class Crypt
{
private const string password = "password";
private readonly static byte[] salt = Encoding.ASCII.GetBytes(password.Length.ToString());
public static string FixedEncryptor(string content)
{
var cipher = new RijndaelManaged();
var plain = Encoding.Unicode.GetBytes(content);
var key = new PasswordDeriveBytes(password, salt);
using (var encrypt = cipher.CreateEncryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream())
using (var crypto = new CryptoStream(stream, encrypt, CryptoStreamMode.Write))
{
crypto.Write(plain, 0, plain.Length);
crypto.FlushFinalBlock();
return Convert.ToBase64String(stream.ToArray());
}
}
public static string Encryptor(string content)
{
var cipher = new RijndaelManaged();
var plain = Encoding.Unicode.GetBytes(content);
var key = new PasswordDeriveBytes("password", Encoding.ASCII.GetBytes("password"));
using (var encrypt = cipher.CreateEncryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream())
using (var crypto = new CryptoStream(stream, encrypt, CryptoStreamMode.Write))
{
crypto.Write(plain, 0, plain.Length);
crypto.FlushFinalBlock();
return Convert.ToBase64String(stream.ToArray());
}
}
public static string FixedDecryptor(string content)
{
var cipher = new RijndaelManaged();
var encrypted = Convert.FromBase64String(content);
var key = new PasswordDeriveBytes(password, salt);
using (var decryptor = cipher.CreateDecryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream(encrypted))
using (var crypto = new CryptoStream(stream, decryptor, CryptoStreamMode.Read))
{
byte[] plain = new byte[encrypted.Length];
int decrypted = crypto.Read(plain, 0, plain.Length);
string data = Encoding.Unicode.GetString(plain, 0, decrypted);
return data;
}
}
public static string Decryptor(string content)
{
var cipher = new RijndaelManaged();
var encrypted = Convert.FromBase64String(content);
var key = new PasswordDeriveBytes("password", Encoding.ASCII.GetBytes("password"));
using (var decryptor = cipher.CreateDecryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream(encrypted))
using (var crypto = new CryptoStream(stream, decryptor, CryptoStreamMode.Read))
{
byte[] plain = new byte[encrypted.Length];
int decrypted = crypto.Read(plain, 0, plain.Length);
string data = Encoding.Unicode.GetString(plain, 0, decrypted);
return data;
}
}
}
Fiddel的代码。
然而，这仍然不是 "correct" 做事的方式。请参阅 答案
下面和 Fiddle 中的代码不是用于生产，而是用于教育目的。我不想修复任何东西，因为我有一个可行的解决方案。但是，我想知道为什么：
var password = "password";
var salt = Encoding.ASCII.GetBytes(password.Length.ToString());
var secret = new PasswordDeriveBytes(password, salt);
当上面的实现后，下面的方法FixedEncryptor将起作用。
// Valid:
public static string FixedEncryptor(string content)
{
var cipher = new RijndaelManaged();
var plain = Encoding.Unicode.GetBytes(content);
var key = new PasswordDeriveBytes(password, salt);
using (var encrypt = cipher.CreateEncryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream())
using (var crypto = new CryptoStream(stream, encrypt, CryptoStreamMode.Write))
{
crypto.Write(plain, 0, plain.Length);
crypto.FlushFinalBlock();
return Convert.ToBase64String(stream.ToArray());
}
}
但是，如果您实施：
var secret = new PasswordDeriveBytes("password",
Encoding.ASCII.GetBytes("password"));
代码会突然产生：
Run-time exception (line 70): Padding is invalid and cannot be removed.
Stack Trace:
[System.Security.Cryptography.CryptographicException: Padding is invalid and cannot be removed.] at Crypt.Decryptor(String content): line 70 at Program.Main(): line 17
如下方法表示：
// Invalid:
public static string Encryptor(string content)
{
var cipher = new RijndaelManaged();
var plain = Encoding.Unicode.GetBytes(content);
var key = new PasswordDeriveBytes("password", Encoding.ASCII.GetBytes("password"));
using (var encrypt = cipher.CreateEncryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream())
using (var crypto = new CryptoStream(stream, encrypt, CryptoStreamMode.Write))
{
crypto.Write(plain, 0, plain.Length);
crypto.FlushFinalBlock();
return Convert.ToBase64String(stream.ToArray());
}
}
那为什么一个能解密成功，而另一个解密不正确，出现上述错误呢？
一个Fiddle的小例子是here.
首先，你生成盐的方法一点都不安全；其次，PasswordDerivedBytes 已弃用，您应该查看其继任者 Rfc2898DeriveBytes.
尝试类似以下的操作 - 请注意，这需要一些 using 语句：System、System.IO、System.Security.Cryptography 和 System.Text。
简单地用Encrypt(PlainText, Password)加密数据并用Decrypt(EncryptedData, Password)再次解密。盐作为前 16 个字节卷入加密数据，并且在每个 encryption/decryption 轮中完全随机。
此代码是我自己的开源密码管理器的一部分。
/*
* Encryption/Decryption, based on AES256 and PBKDF2
*/
public string Encrypt (string plainText, string passPhrase, bool fast_encrypt = false)
{
string result;
using (Rijndael algR = Rijndael.Create ()) {
RNGCryptoServiceProvider rngC = new RNGCryptoServiceProvider ();
byte[] iv = new byte[16];
rngC.GetBytes (iv);
Rfc2898DeriveBytes derived = new Rfc2898DeriveBytes (passPhrase, iv, fast_encrypt ? 10 : 3000);
algR.KeySize = 256;
algR.BlockSize = 128;
algR.Key = derived.GetBytes (32);
algR.IV = iv;
using (MemoryStream memoryStream = new MemoryStream ()) {
memoryStream.Write (iv, 0, 16);
using (CryptoStream cryptoStreamEncrypt = new CryptoStream (memoryStream, algR.CreateEncryptor (algR.Key, algR.IV), CryptoStreamMode.Write)) {
using (StreamWriter streamWriterEncrypt = new StreamWriter (cryptoStreamEncrypt)) {
streamWriterEncrypt.Write (plainText);
}
}
result = Convert.ToBase64String (memoryStream.ToArray ());
}
}
return result;
}
public string Decrypt (string cipherText, string passPhrase, bool fast_decrypt = false)
{
string result;
using (Rijndael algR = Rijndael.Create ()) {
using (MemoryStream memoryStream = new MemoryStream (Convert.FromBase64String (cipherText))) {
byte[] iv = new byte[16];
memoryStream.Read (iv, 0, 16);
Rfc2898DeriveBytes derived = new Rfc2898DeriveBytes (passPhrase, iv, fast_decrypt ? 10 : 3000);
algR.KeySize = 256;
algR.BlockSize = 128;
algR.Key = derived.GetBytes (32);
algR.IV = iv;
using (CryptoStream cryptoStreamDecrypt = new CryptoStream (memoryStream, algR.CreateDecryptor (algR.Key, algR.IV), CryptoStreamMode.Read)) {
using (StreamReader streamReaderDecrypt = new StreamReader (cryptoStreamDecrypt)) {
result = streamReaderDecrypt.ReadToEnd ();
}
}
}
}
return result;
}
根据您发布的代码示例，您的问题来自于您使用了两种不同的盐。
在 FixedEncryptor 中，您使用
的盐Encoding.ASCII.GetBytes(password.Length.ToString());
编码为等于 { 56 } 的字节数组，这是因为 Length returns 8 然后在 returns 上调用 ToString()您将其转换为 ascii 值 56 的字符串“8”。
在 Encryptor 中，您使用
的盐Encoding.ASCII.GetBytes("password")
编码为字节数组等于{ 112, 97, 115, 115, 119, 111, 114, 100}，即字符"p"、"a"、"s"、[=46=的ascii值]、"w"、"o"、"r" 和 "d"。
您 运行 遇到的问题是您只尝试在解密函数中使用 { 56 }，所以您的问题归结为 您的加密函数和解密函数使用两种不同的盐.
如果我制作一个新的 Decrypter 以使用与 Encryptor 相同的盐和密码，然后制作一个单独的 FixedDecryptor 以匹配 FixedEncryptor 所有内容的盐会很好
public class Program
{
public static void Main()
{
var message = "Hello World!";
var fixedCipherText = Crypt.FixedEncryptor(message);
var cipherText = Crypt.Encryptor(message);
Console.WriteLine(cipherText);
Console.WriteLine(fixedCipherText);
var plainText = Crypt.Decryptor(cipherText);
var fixedPlainText = Crypt.FixedDecryptor(fixedCipherText);
Console.WriteLine(plainText);
Console.WriteLine(fixedPlainText);
}
}
public static class Crypt
{
private const string password = "password";
private readonly static byte[] salt = Encoding.ASCII.GetBytes(password.Length.ToString());
public static string FixedEncryptor(string content)
{
var cipher = new RijndaelManaged();
var plain = Encoding.Unicode.GetBytes(content);
var key = new PasswordDeriveBytes(password, salt);
using (var encrypt = cipher.CreateEncryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream())
using (var crypto = new CryptoStream(stream, encrypt, CryptoStreamMode.Write))
{
crypto.Write(plain, 0, plain.Length);
crypto.FlushFinalBlock();
return Convert.ToBase64String(stream.ToArray());
}
}
public static string Encryptor(string content)
{
var cipher = new RijndaelManaged();
var plain = Encoding.Unicode.GetBytes(content);
var key = new PasswordDeriveBytes("password", Encoding.ASCII.GetBytes("password"));
using (var encrypt = cipher.CreateEncryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream())
using (var crypto = new CryptoStream(stream, encrypt, CryptoStreamMode.Write))
{
crypto.Write(plain, 0, plain.Length);
crypto.FlushFinalBlock();
return Convert.ToBase64String(stream.ToArray());
}
}
public static string FixedDecryptor(string content)
{
var cipher = new RijndaelManaged();
var encrypted = Convert.FromBase64String(content);
var key = new PasswordDeriveBytes(password, salt);
using (var decryptor = cipher.CreateDecryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream(encrypted))
using (var crypto = new CryptoStream(stream, decryptor, CryptoStreamMode.Read))
{
byte[] plain = new byte[encrypted.Length];
int decrypted = crypto.Read(plain, 0, plain.Length);
string data = Encoding.Unicode.GetString(plain, 0, decrypted);
return data;
}
}
public static string Decryptor(string content)
{
var cipher = new RijndaelManaged();
var encrypted = Convert.FromBase64String(content);
var key = new PasswordDeriveBytes("password", Encoding.ASCII.GetBytes("password"));
using (var decryptor = cipher.CreateDecryptor(key.GetBytes(32), key.GetBytes(16)))
using (var stream = new MemoryStream(encrypted))
using (var crypto = new CryptoStream(stream, decryptor, CryptoStreamMode.Read))
{
byte[] plain = new byte[encrypted.Length];
int decrypted = crypto.Read(plain, 0, plain.Length);
string data = Encoding.Unicode.GetString(plain, 0, decrypted);
return data;
}
}
}
Fiddel的代码。
然而，这仍然不是 "correct" 做事的方式。请参阅