在C#中,最现代(最佳)的方法是什么来满足以下需求?
string encryptedString = SomeStaticClass.Encrypt(sourceString);
string decryptedString = SomeStaticClass.Decrypt(encryptedString);
但是最好不要涉及盐、密钥、使用 byte[] 等操作。
我一直在搜索,但是找到的结果让我感到困惑(您可以查看类似的 SO 问题列表来了解这是一个具有误导性的问题)。
在C#中,最现代(最佳)的方法是什么来满足以下需求?
string encryptedString = SomeStaticClass.Encrypt(sourceString);
string decryptedString = SomeStaticClass.Decrypt(encryptedString);
但是最好不要涉及盐、密钥、使用 byte[] 等操作。
我一直在搜索,但是找到的结果让我感到困惑(您可以查看类似的 SO 问题列表来了解这是一个具有误导性的问题)。
更新于2015年12月23日:由于这个答案似乎得到了很多赞,因此我已经根据评论和反馈修复了愚蠢的错误并总体上改进了代码。请参见文章末尾的具体改进列表。
正如其他人所说,加密学并不简单,最好避免“自行开发”加密算法。
但是,您可以“自行开发”一个包装类,用于包装内置的RijndaelManaged
加密类之类的东西。
Rijndael是当前高级加密标准的算法名称,因此您肯定在使用可以被认为是“最佳实践”的加密算法。
RijndaelManaged
类确实通常需要您与字节数组、盐、密钥、初始化向量等打交道,但这正是可以在您的“包装器”类中抽象出的详细信息。
下面的类是我写的一段时间前执行您想要的事情的简单单个方法调用,允许使用基于字符串的密码加密基于字符串的纯文本,并且表示为字符串的结果也被加密。当然,有一个相应的方法使用相同的密码解密加密的字符串。
与此代码的第一版本不同,该版本将在每次生成随机盐和IV值时使用完全相同的盐和IV值。由于盐和IV必须在给定字符串的加密和解密之间相同,因此在加密时将盐和IV附加到密文中,并再次从中提取它们以执行解密。这样做的结果是,使用完全相同的密码加密完全相同的纯文本每次都会得到完全不同的密文结果。
使用这种方法的“强度”来自使用RijndaelManaged
类为您执行加密,以及使用System.Security.Cryptography
命名空间的Rfc2898DeriveBytes函数,该函数将使用基于您提供的基于字符串的密码的标准和安全算法(具体来说是PBKDF2)生成加密密钥。(请注意,这是第一版使用旧PBKDF1算法的改进。)
最后需要注意的是,这仍然是一个未经身份验证的加密。加密本身只提供隐私(即消息对第三方未知),而身份认证加密旨在同时提供隐私和真实性(即接收者知道消息是由发送者发送的)。
如果不知道您的确切需求,很难判断此处的代码是否足够安全,但它已经被设计为在相对简单实现与“质量”之间取得良好的平衡。例如,如果您加密字符串的“接收者”直接从可信“发送者”接收字符串,则可能甚至无需进行身份验证。
如果您需要更复杂的、提供身份认证加密的东西,请查看此文章中的实现。
以下是代码:
using System;
using System.Text;
using System.Security.Cryptography;
using System.IO;
using System.Linq;
namespace EncryptStringSample
{
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 = 256;
// 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 = Generate256BitsOfRandomEntropy();
var ivStringBytes = Generate256BitsOfRandomEntropy();
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 = 256;
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] + [32 bytes of IV] + [n bytes of CipherText]
var cipherTextBytesWithSaltAndIv = Convert.FromBase64String(cipherText);
// Get the saltbytes by extracting the first 32 bytes from the supplied cipherText bytes.
var saltStringBytes = cipherTextBytesWithSaltAndIv.Take(Keysize / 8).ToArray();
// Get the IV bytes by extracting the next 32 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 = 256;
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))
using (var streamReader = new StreamReader(cryptoStream, Encoding.UTF8))
{
return streamReader.ReadToEnd();
}
}
}
}
}
}
private static byte[] Generate256BitsOfRandomEntropy()
{
var randomBytes = new byte[32]; // 32 Bytes will give us 256 bits.
using (var rngCsp = new RNGCryptoServiceProvider())
{
// Fill the array with cryptographically secure random bytes.
rngCsp.GetBytes(randomBytes);
}
return randomBytes;
}
}
}
以上的类可以通过类似以下代码的方式轻松使用:
using System;
namespace EncryptStringSample
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Please enter a password to use:");
string password = Console.ReadLine();
Console.WriteLine("Please enter a string to encrypt:");
string plaintext = Console.ReadLine();
Console.WriteLine("");
Console.WriteLine("Your encrypted string is:");
string encryptedstring = StringCipher.Encrypt(plaintext, password);
Console.WriteLine(encryptedstring);
Console.WriteLine("");
Console.WriteLine("Your decrypted string is:");
string decryptedstring = StringCipher.Decrypt(encryptedstring, password);
Console.WriteLine(decryptedstring);
Console.WriteLine("");
Console.WriteLine("Press any key to exit...");
Console.ReadLine();
}
}
}
您可以在这里下载一个简单的VS2013示例解决方案(其中包括一些单元测试)。
更新 23/Dec/2015: 代码的具体改进列表如下:
using System.IO;
using System.Text;
using System.Security.Cryptography;
public static class EncryptionHelper
{
public static string Encrypt(string clearText)
{
string EncryptionKey = "abc123";
byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);
using (Aes encryptor = Aes.Create())
{
Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
encryptor.Key = pdb.GetBytes(32);
encryptor.IV = pdb.GetBytes(16);
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(clearBytes, 0, clearBytes.Length);
cs.Close();
}
clearText = Convert.ToBase64String(ms.ToArray());
}
}
return clearText;
}
public static string Decrypt(string cipherText)
{
string EncryptionKey = "abc123";
cipherText = cipherText.Replace(" ", "+");
byte[] cipherBytes = Convert.FromBase64String(cipherText);
using (Aes encryptor = Aes.Create())
{
Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
encryptor.Key = pdb.GetBytes(32);
encryptor.IV = pdb.GetBytes(16);
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(cipherBytes, 0, cipherBytes.Length);
cs.Close();
}
cipherText = Encoding.Unicode.GetString(ms.ToArray());
}
}
return cipherText;
}
}
public static string Encrypt(string clearText, string encryptionKey)
这样一来,您就可以为每个方法调用使用唯一的密钥。 - sojim2cs
被多次释放。在 Encrypt
和 Decrypt
方法中,我们不需要重复的 cs.Close()
语句,因为一旦控制流离开 using
块,它们都会被释放。 - Jatin SanghviRijndaelManaged
的 ASP.NET Core,您可以使用 IDataProtectionProvider
。public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddDataProtection();
}
// ...
}
然后,您将能够注入 IDataProtectionProvider
实例并使用它来加密/解密数据:
public class MyService : IService
{
private const string Purpose = "my protection purpose";
private readonly IDataProtectionProvider _provider;
public MyService(IDataProtectionProvider provider)
{
_provider = provider;
}
public string Encrypt(string plainText)
{
var protector = _provider.CreateProtector(Purpose);
return protector.Protect(plainText);
}
public string Decrypt(string cipherText)
{
var protector = _provider.CreateProtector(Purpose);
return protector.Unprotect(cipherText);
}
}
阅读这篇文章获取更多详情。
尝试使用这个类:
public class DataEncryptor
{
TripleDESCryptoServiceProvider symm;
#region Factory
public DataEncryptor()
{
this.symm = new TripleDESCryptoServiceProvider();
this.symm.Padding = PaddingMode.PKCS7;
}
public DataEncryptor(TripleDESCryptoServiceProvider keys)
{
this.symm = keys;
}
public DataEncryptor(byte[] key, byte[] iv)
{
this.symm = new TripleDESCryptoServiceProvider();
this.symm.Padding = PaddingMode.PKCS7;
this.symm.Key = key;
this.symm.IV = iv;
}
#endregion
#region Properties
public TripleDESCryptoServiceProvider Algorithm
{
get { return symm; }
set { symm = value; }
}
public byte[] Key
{
get { return symm.Key; }
set { symm.Key = value; }
}
public byte[] IV
{
get { return symm.IV; }
set { symm.IV = value; }
}
#endregion
#region Crypto
public byte[] Encrypt(byte[] data) { return Encrypt(data, data.Length); }
public byte[] Encrypt(byte[] data, int length)
{
try
{
// Create a MemoryStream.
var ms = new MemoryStream();
// Create a CryptoStream using the MemoryStream
// and the passed key and initialization vector (IV).
var cs = new CryptoStream(ms,
symm.CreateEncryptor(symm.Key, symm.IV),
CryptoStreamMode.Write);
// Write the byte array to the crypto stream and flush it.
cs.Write(data, 0, length);
cs.FlushFinalBlock();
// Get an array of bytes from the
// MemoryStream that holds the
// encrypted data.
byte[] ret = ms.ToArray();
// Close the streams.
cs.Close();
ms.Close();
// Return the encrypted buffer.
return ret;
}
catch (CryptographicException ex)
{
Console.WriteLine("A cryptographic error occured: {0}", ex.Message);
}
return null;
}
public string EncryptString(string text)
{
return Convert.ToBase64String(Encrypt(Encoding.UTF8.GetBytes(text)));
}
public byte[] Decrypt(byte[] data) { return Decrypt(data, data.Length); }
public byte[] Decrypt(byte[] data, int length)
{
try
{
// Create a new MemoryStream using the passed
// array of encrypted data.
MemoryStream ms = new MemoryStream(data);
// Create a CryptoStream using the MemoryStream
// and the passed key and initialization vector (IV).
CryptoStream cs = new CryptoStream(ms,
symm.CreateDecryptor(symm.Key, symm.IV),
CryptoStreamMode.Read);
// Create buffer to hold the decrypted data.
byte[] result = new byte[length];
// Read the decrypted data out of the crypto stream
// and place it into the temporary buffer.
cs.Read(result, 0, result.Length);
return result;
}
catch (CryptographicException ex)
{
Console.WriteLine("A cryptographic error occured: {0}", ex.Message);
}
return null;
}
public string DecryptString(string data)
{
return Encoding.UTF8.GetString(Decrypt(Convert.FromBase64String(data))).TrimEnd('\0');
}
#endregion
}
并像这样使用它:
string message="A very secret message here.";
DataEncryptor keys=new DataEncryptor();
string encr=keys.EncryptString(message);
// later
string actual=keys.DecryptString(encr);
.NET 2.0
,最近微软已经更新了加密命名空间。我怀疑我的答案现在已经过时了。 - John Alexiou如果您需要在内存中存储密码并希望进行加密,您应该使用 SecureString:
http://msdn.microsoft.com/zh-cn/library/system.security.securestring.aspx
对于更普遍的用途,我建议使用 FIPS 批准算法,例如高级加密标准(Advanced Encryption Standard),以前称为 Rijndael。请参阅此页面以获取示例实现:
http://msdn.microsoft.com/zh-cn/library/system.security.cryptography.rijndael.aspx
ProtectedData
类,该类使用用户的登录凭据对数据进行加密。ProtectedData
不是正确的工具。(除非你在一个域中,这样他们就可以在任何地方使用相同的用户) - SLaksDataProtectionScope.CurrentUser
只能在同一台(物理)机器上可靠地使用。 - Tewr我见过的最简单的加密方式是通过RSA
可以查看MSDN上的相关内容:http://msdn.microsoft.com/en-us/library/system.security.cryptography.rsacryptoserviceprovider.aspx
这确实涉及到使用字节,但归根结底,您确实希望加密和解密难以破解,否则将很容易被黑客攻击。
Encoding.UTF8
。 - SLaks