如何在c#中加密和解密字符串?
当前回答
免责声明:此解决方案只能用于未公开的静态数据(例如配置文件或DB)。只有在这种情况下，快速和肮脏的解决方案才能被认为比@jbtule的解决方案更好，因为它的维护更低。
原来的帖子: 我发现jbtule的答案对于一个快速和肮脏的安全AES字符串加密有点复杂，Brett的答案有一个错误，初始化向量是一个固定的值，使它容易受到填充攻击，所以我修复了Brett的代码，并添加了一个随机IV，添加到chitered字符串，创建一个不同的加密值，每个加密相同的值:
加密:
public static string Encrypt(string clearText)
{
byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);
using (Aes encryptor = Aes.Create())
{
byte[] IV = new byte[15];
rand.NextBytes(IV);
Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, IV);
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(IV) + Convert.ToBase64String(ms.ToArray());
}
}
return clearText;
}
解密:
public static string Decrypt(string cipherText)
{
byte[] IV = Convert.FromBase64String(cipherText.Substring(0, 20));
cipherText = cipherText.Substring(20).Replace(" ", "+");
byte[] cipherBytes = Convert.FromBase64String(cipherText);
using (Aes encryptor = Aes.Create())
{
Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, IV);
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;
}
将EncryptionKey替换为您的密钥。 在我的实现中，密钥被保存在配置文件(web.config\app.config)中，因为您不应该将其硬编码保存。配置文件也应该加密，这样密钥就不会被保存为明文。
protected static string _Key = "";
protected static string EncryptionKey
{
get
{
if (String.IsNullOrEmpty(_Key))
{
_Key = ConfigurationManager.AppSettings["AESKey"].ToString();
}
return _Key;
}
}
其他回答
免责声明:此解决方案只能用于未公开的静态数据(例如配置文件或DB)。只有在这种情况下，快速和肮脏的解决方案才能被认为比@jbtule的解决方案更好，因为它的维护更低。
原来的帖子: 我发现jbtule的答案对于一个快速和肮脏的安全AES字符串加密有点复杂，Brett的答案有一个错误，初始化向量是一个固定的值，使它容易受到填充攻击，所以我修复了Brett的代码，并添加了一个随机IV，添加到chitered字符串，创建一个不同的加密值，每个加密相同的值:
加密:
public static string Encrypt(string clearText)
{
byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);
using (Aes encryptor = Aes.Create())
{
byte[] IV = new byte[15];
rand.NextBytes(IV);
Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, IV);
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(IV) + Convert.ToBase64String(ms.ToArray());
}
}
return clearText;
}
解密:
public static string Decrypt(string cipherText)
{
byte[] IV = Convert.FromBase64String(cipherText.Substring(0, 20));
cipherText = cipherText.Substring(20).Replace(" ", "+");
byte[] cipherBytes = Convert.FromBase64String(cipherText);
using (Aes encryptor = Aes.Create())
{
Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, IV);
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;
}
将EncryptionKey替换为您的密钥。 在我的实现中，密钥被保存在配置文件(web.config\app.config)中，因为您不应该将其硬编码保存。配置文件也应该加密，这样密钥就不会被保存为明文。
protected static string _Key = "";
protected static string EncryptionKey
{
get
{
if (String.IsNullOrEmpty(_Key))
{
_Key = ConfigurationManager.AppSettings["AESKey"].ToString();
}
return _Key;
}
}
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
public class Program
{
public static void Main()
{
var key = Encoding.UTF8.GetBytes("SUkbqO2ycDo7QwpR25kfgmC7f8CoyrZy");
var data = Encoding.UTF8.GetBytes("testData");
//Encrypt data
var encrypted = CryptoHelper.EncryptData(data,key);
//Decrypt data
var decrypted = CryptoHelper.DecryptData(encrypted,key);
//Display result
Console.WriteLine(Encoding.UTF8.GetString(decrypted));
}
}
public static class CryptoHelper
{
public static byte[] EncryptData(byte[] data, byte[] key)
{
using (var aesAlg = Aes.Create())
{
aesAlg.Mode = CipherMode.CBC;
using (var encryptor = aesAlg.CreateEncryptor(key, aesAlg.IV))
{
using (var msEncrypt = new MemoryStream())
{
msEncrypt.Write(aesAlg.IV, 0, aesAlg.IV.Length);
using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
csEncrypt.Write(data, 0, data.Length);
return msEncrypt.ToArray();
}
}
}
}
public static byte[] DecryptData(byte[] encrypted, byte[] key)
{
var iv = new byte[16];
Buffer.BlockCopy(encrypted, 0, iv, 0, iv.Length);
using (var aesAlg = Aes.Create())
{
aesAlg.Mode = CipherMode.CBC;
using (var decryptor = aesAlg.CreateDecryptor(key, iv))
{
using (var msDecrypt = new MemoryStream(encrypted, iv.Length, encrypted.Length - iv.Length))
{
using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (var resultStream = new MemoryStream())
{
csDecrypt.CopyTo(resultStream);
return resultStream.ToArray();
}
}
}
}
}
}
}
这是布雷特安排在这里的课程。然而，我做了一个轻微的编辑，因为我在使用URL字符串加密和解密时收到了错误“无效的长度为一个Base-64字符数组”。
public class CryptoURL
{
private static byte[] _salt = Encoding.ASCII.GetBytes("Catto_Salt_Enter_Any_Value99");
/// <summary>
/// Encrypt the given string using AES. The string can be decrypted using
/// DecryptStringAES(). The sharedSecret parameters must match.
/// The SharedSecret for the Password Reset that is used is in the next line
/// string sharedSecret = "OneUpSharedSecret9";
/// </summary>
/// <param name="plainText">The text to encrypt.</param>
/// <param name="sharedSecret">A password used to generate a key for encryption.</param>
public static string EncryptString(string plainText, string sharedSecret)
{
if (string.IsNullOrEmpty(plainText))
throw new ArgumentNullException("plainText");
if (string.IsNullOrEmpty(sharedSecret))
throw new ArgumentNullException("sharedSecret");
string outStr = null; // Encrypted string to return
RijndaelManaged aesAlg = null; // RijndaelManaged object used to encrypt the data.
try
{
// generate the key from the shared secret and the salt
Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(sharedSecret, _salt);
// Create a RijndaelManaged object
aesAlg = new RijndaelManaged();
aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);
// Create a decryptor to perform the stream transform.
ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
// Create the streams used for encryption.
using (MemoryStream msEncrypt = new MemoryStream())
{
// prepend the IV
msEncrypt.Write(BitConverter.GetBytes(aesAlg.IV.Length), 0, sizeof(int));
msEncrypt.Write(aesAlg.IV, 0, aesAlg.IV.Length);
using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
{
//Write all data to the stream.
swEncrypt.Write(plainText);
}
}
outStr = HttpServerUtility.UrlTokenEncode(msEncrypt.ToArray());
//outStr = Convert.ToBase64String(msEncrypt.ToArray());
// you may need to add a reference. right click reference in solution explorer => "add Reference" => .NET tab => select "System.Web"
}
}
finally
{
// Clear the RijndaelManaged object.
if (aesAlg != null)
aesAlg.Clear();
}
// Return the encrypted bytes from the memory stream.
return outStr;
}
/// <summary>
/// Decrypt the given string. Assumes the string was encrypted using
/// EncryptStringAES(), using an identical sharedSecret.
/// </summary>
/// <param name="cipherText">The text to decrypt.</param>
/// <param name="sharedSecret">A password used to generate a key for decryption.</param>
public static string DecryptString(string cipherText, string sharedSecret)
{
if (string.IsNullOrEmpty(cipherText))
throw new ArgumentNullException("cipherText");
if (string.IsNullOrEmpty(sharedSecret))
throw new ArgumentNullException("sharedSecret");
// Declare the RijndaelManaged object
// used to decrypt the data.
RijndaelManaged aesAlg = null;
// Declare the string used to hold
// the decrypted text.
string plaintext = null;
byte[] inputByteArray;
try
{
// generate the key from the shared secret and the salt
Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(sharedSecret, _salt);
// Create the streams used for decryption.
//byte[] bytes = Convert.FromBase64String(cipherText);
inputByteArray = HttpServerUtility.UrlTokenDecode(cipherText);
using (MemoryStream msDecrypt = new MemoryStream(inputByteArray))
{
// Create a RijndaelManaged object
// with the specified key and IV.
aesAlg = new RijndaelManaged();
aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);
// Get the initialization vector from the encrypted stream
aesAlg.IV = ReadByteArray(msDecrypt);
// Create a decrytor to perform the stream transform.
ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (StreamReader srDecrypt = new StreamReader(csDecrypt))
// Read the decrypted bytes from the decrypting stream
// and place them in a string.
plaintext = srDecrypt.ReadToEnd();
}
}
}
catch (System.Exception ex)
{
return "ERROR";
//throw ex;
}
finally
{
// Clear the RijndaelManaged object.
if (aesAlg != null)
aesAlg.Clear();
}
return plaintext;
}
static string ConvertStringArrayToString(string[] array)
{
//
// Concatenate all the elements into a StringBuilder.
//
StringBuilder builder = new StringBuilder();
foreach (string value in array)
{
builder.Append(value);
builder.Append('.');
}
return builder.ToString();
}
private static byte[] ReadByteArray(Stream s)
{
byte[] rawLength = new byte[sizeof(int)];
if (s.Read(rawLength, 0, rawLength.Length) != rawLength.Length)
{
throw new SystemException("Stream did not contain properly formatted byte array");
}
byte[] buffer = new byte[BitConverter.ToInt32(rawLength, 0)];
if (s.Read(buffer, 0, buffer.Length) != buffer.Length)
{
throw new SystemException("Did not read byte array properly");
}
return buffer;
}
}
下面是一个简单的例子，在c#中使用AES CBC模式加密字符串，并使用随机IV和HMAC和密码派生密钥，以显示基本的移动部分:
private byte[] EncryptBytes(byte[] key, byte[] plaintext)
{
using (var cipher = new RijndaelManaged { Key = key })
{
using (var encryptor = cipher.CreateEncryptor())
{
var ciphertext = encryptor.TransformFinalBlock(plaintext, 0, plaintext.Length);
// IV is prepended to ciphertext
return cipher.IV.Concat(ciphertext).ToArray();
}
}
}
private byte[] DecryptBytes(byte[] key, byte[] packed)
{
using (var cipher = new RijndaelManaged { Key = key })
{
int ivSize = cipher.BlockSize / 8;
cipher.IV = packed.Take(ivSize).ToArray();
using (var encryptor = cipher.CreateDecryptor())
{
return encryptor.TransformFinalBlock(packed, ivSize, packed.Length - ivSize);
}
}
}
private byte[] AddMac(byte[] key, byte[] data)
{
using (var hmac = new HMACSHA256(key))
{
var macBytes = hmac.ComputeHash(data);
// HMAC is appended to data
return data.Concat(macBytes).ToArray();
}
}
private bool BadMac(byte[] found, byte[] computed)
{
int mismatch = 0;
// Aim for consistent timing regardless of inputs
for (int i = 0; i < found.Length; i++)
{
mismatch += found[i] == computed[i] ? 0 : 1;
}
return mismatch != 0;
}
private byte[] RemoveMac(byte[] key, byte[] data)
{
using (var hmac = new HMACSHA256(key))
{
int macSize = hmac.HashSize / 8;
var packed = data.Take(data.Length - macSize).ToArray();
var foundMac = data.Skip(packed.Length).ToArray();
var computedMac = hmac.ComputeHash(packed);
if (this.BadMac(foundMac, computedMac))
{
throw new Exception("Bad MAC");
}
return packed;
}
}
private List<byte[]> DeriveTwoKeys(string password)
{
var salt = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
var kdf = new Rfc2898DeriveBytes(password, salt, 10000);
var bytes = kdf.GetBytes(32); // Two keys 128 bits each
return new List<byte[]> { bytes.Take(16).ToArray(), bytes.Skip(16).ToArray() };
}
public byte[] EncryptString(string password, String message)
{
var keys = this.DeriveTwoKeys(password);
var plaintext = Encoding.UTF8.GetBytes(message);
var packed = this.EncryptBytes(keys[0], plaintext);
return this.AddMac(keys[1], packed);
}
public String DecryptString(string password, byte[] secret)
{
var keys = this.DeriveTwoKeys(password);
var packed = this.RemoveMac(keys[1], secret);
var plaintext = this.DecryptBytes(keys[0], packed);
return Encoding.UTF8.GetString(plaintext);
}
public void Example()
{
var password = "correcthorsebatterystaple";
var secret = this.EncryptString(password, "Hello World");
Console.WriteLine("secret: " + BitConverter.ToString(secret));
var recovered = this.DecryptString(password, secret);
Console.WriteLine(recovered);
}
我在这里复制了一个类似问题的答案:c#的简单双向加密。
基于多个答案和评论。
加密文本前的随机初始化向量(@jbtule) 使用TransformFinalBlock()代替MemoryStream (@RenniePet) 没有预填充键，以避免任何人复制和粘贴灾难 正确处理和使用模式
代码:
/// <summary>
/// Simple encryption/decryption using a random initialization vector
/// and prepending it to the crypto text.
/// </summary>
/// <remarks>Based on multiple answers in https://stackoverflow.com/questions/165808/simple-two-way-encryption-for-c-sharp </remarks>
public class SimpleAes : IDisposable
{
/// <summary>
/// Initialization vector length in bytes.
/// </summary>
private const int IvBytes = 16;
/// <summary>
/// Must be exactly 16, 24 or 32 characters long.
/// </summary>
private static readonly byte[] Key = Convert.FromBase64String("FILL ME WITH 16, 24 OR 32 CHARS");
private readonly UTF8Encoding _encoder;
private readonly ICryptoTransform _encryptor;
private readonly RijndaelManaged _rijndael;
public SimpleAes()
{
_rijndael = new RijndaelManaged {Key = Key};
_rijndael.GenerateIV();
_encryptor = _rijndael.CreateEncryptor();
_encoder = new UTF8Encoding();
}
public string Decrypt(string encrypted)
{
return _encoder.GetString(Decrypt(Convert.FromBase64String(encrypted)));
}
public void Dispose()
{
_rijndael.Dispose();
_encryptor.Dispose();
}
public string Encrypt(string unencrypted)
{
return Convert.ToBase64String(Encrypt(_encoder.GetBytes(unencrypted)));
}
private byte[] Decrypt(byte[] buffer)
{
// IV is prepended to cryptotext
byte[] iv = buffer.Take(IvBytes).ToArray();
using (ICryptoTransform decryptor = _rijndael.CreateDecryptor(_rijndael.Key, iv))
{
return decryptor.TransformFinalBlock(buffer, IvBytes, buffer.Length - IvBytes);
}
}
private byte[] Encrypt(byte[] buffer)
{
// Prepend cryptotext with IV
byte[] inputBuffer = _rijndael.IV.Concat(buffer).ToArray();
return _encryptor.TransformFinalBlock(inputBuffer, IvBytes, buffer.Length);
}
}
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