#region 獲取由SHA1加密的字符串
public static string EncryptToSHA1(string str)
{
SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider();
byte[] str1 = Encoding.UTF8.GetBytes(str);
byte[] str2 = sha1.ComputeHash(str1);
sha1.Clear();
(sha1 as IDisposable).Dispose();
return Convert.ToBase64String(str2);
}
#endregion

---------------RSA加密

RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
RSAParameters rsaParamsExcludePrivate=rsa.ExportParameters(false);
RSAParameters rsaParamsIncludePrivate=rsa.ExportParameters(true);

Public byte [ ] RSAEncrypt ( byte [ ] b)
{
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
rsa.ImportParameters(rsaParamsExcludePrivate); //導入公鑰
byte [] EncryptedData=rsa.Encrypt(DataToEncrypt,false);
return EncryptedData;
}
解密時只要把rsa.ImportParameters(rsaParamsExcludePrivate)換成rsa.ImportParameters(rsaParamsExcludePrivate)，再把Encrypt換成Decrypt就行了。

保存和加載RSA參數：RSA參數可以保存為XML格式，下面代碼說明了如何保存和加載（只列出了關鍵部分）

保存
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
StreamWriter writer=new StreamWriter(@"d:\PublicAndPrivateKey.xml");
string PPKeyXml=rsa.ToXmlString(true);//保存私鑰 writer.Write(PPKeyXml);
writer.Close();
writer=new StreamWriter(@"d:\PublicKey.xml");
string PKeyXml=rsa.ToXmlString(false);//保存公鑰
writer.Write(PKeyXml);
writer.Close();

讀取
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
StreamReader reader=new StreamReader(@"d:\PublicKey.xml");
string PKey=reader.ReadToEnd();
rsa.FromXmlString(PKey);
reader.Close();
StreamReader reader=new StreamReader(@"d:\PublicAndPrivateKey.xml");
string PPKey=reader.ReadToEnd();
reader.Close();

#region des實現

/// <summary>
/// Des默認密鑰向量
/// </summary>
public static byte[] DesIv = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
/// <summary>
/// Des加解密鑰必須8位
/// </summary>
public const string DesKey = "deskey8w";
/// <summary>
/// 獲取Des8位密鑰
/// </summary>
/// <param name="key">Des密鑰字符串</param>
/// <returns>Des8位密鑰</returns>
static byte[] GetDesKey(string key)
{
if (string.IsNullOrEmpty(key))
{
throw new ArgumentNullException("key", "Des密鑰不能為空");
}
if (key.Length > 8)
{
key = key.Substring(0, 8);
}
if (key.Length < 8)
{
// 不足8補全
key = key.PadRight(8, '0');
}
return Encoding.UTF8.GetBytes(key);
}
/// <summary>
/// Des加密
/// </summary>
/// <param name="source">源字符串</param>
/// <param name="key">des密鑰，長度必須8位</param>
/// <param name="iv">密鑰向量</param>
/// <returns>加密后的字符串</returns>
public static string EncryptDes(string source, string key, byte[] iv)
{
using (DESCryptoServiceProvider desProvider = new DESCryptoServiceProvider())
{
byte[] rgbKeys = GetDesKey(key),
rgbIvs = iv,
inputByteArray = Encoding.UTF8.GetBytes(source);
using (MemoryStream memoryStream = new MemoryStream())
{
using (CryptoStream cryptoStream = new CryptoStream(memoryStream, desProvider.CreateEncryptor(rgbKeys, rgbIvs), CryptoStreamMode.Write))
{
cryptoStream.Write(inputByteArray, 0, inputByteArray.Length);
cryptoStream.FlushFinalBlock();
// 1.第一種
return Convert.ToBase64String(memoryStream.ToArray());

// 2.第二種
//StringBuilder result = new StringBuilder();
//foreach (byte b in memoryStream.ToArray())
//{
// result.AppendFormat("{0:X2}", b);
//}
//return result.ToString();
}
}
}
}
/// <summary>
/// Des解密
/// </summary>
/// <param name="source">源字符串</param>
/// <param name="key">des密鑰，長度必須8位</param>
/// <param name="iv">密鑰向量</param>
/// <returns>解密后的字符串</returns>
public static string DecryptDes(string source, string key, byte[] iv)
{
using (DESCryptoServiceProvider desProvider = new DESCryptoServiceProvider())
{
byte[] rgbKeys = GetDesKey(key),
rgbIvs = iv,
inputByteArray = Convert.FromBase64String(source);
using (MemoryStream memoryStream = new MemoryStream())
{
using (CryptoStream cryptoStream = new CryptoStream(memoryStream, desProvider.CreateDecryptor(rgbKeys, rgbIvs), CryptoStreamMode.Write))
{
cryptoStream.Write(inputByteArray, 0, inputByteArray.Length);
cryptoStream.FlushFinalBlock();
return Encoding.UTF8.GetString(memoryStream.ToArray());
}
}
}
}

#endregion

#region aes實現

/// <summary>
/// Aes加解密鑰必須32位
/// </summary>
public static string AesKey = "asekey32w";
/// <summary>
/// 獲取Aes32位密鑰
/// </summary>
/// <param name="key">Aes密鑰字符串</param>
/// <returns>Aes32位密鑰</returns>
static byte[] GetAesKey(string key)
{
if (string.IsNullOrEmpty(key))
{
throw new ArgumentNullException("key", "Aes密鑰不能為空");
}
if (key.Length < 32)
{
// 不足32補全
key = key.PadRight(32, '0');
}
if (key.Length > 32)
{
key = key.Substring(0, 32);
}
return Encoding.UTF8.GetBytes(key);
}
/// <summary>
/// Aes加密
/// </summary>
/// <param name="source">源字符串</param>
/// <param name="key">aes密鑰，長度必須32位</param>
/// <returns>加密后的字符串</returns>
public static string EncryptAes(string source, string key)
{
using (AesCryptoServiceProvider aesProvider = new AesCryptoServiceProvider())
{
aesProvider.Key = GetAesKey(key);
aesProvider.Mode = CipherMode.ECB;
aesProvider.Padding = PaddingMode.PKCS7;
using (ICryptoTransform cryptoTransform = aesProvider.CreateEncryptor())
{
byte[] inputBuffers = Encoding.UTF8.GetBytes(source);
byte[] results = cryptoTransform.TransformFinalBlock(inputBuffers, 0, inputBuffers.Length);
aesProvider.Clear();
aesProvider.Dispose();
return Convert.ToBase64String(results, 0, results.Length);
}
}
}
/// <summary>
/// Aes解密
/// </summary>
/// <param name="source">源字符串</param>
/// <param name="key">aes密鑰，長度必須32位</param>
/// <returns>解密后的字符串</returns>
public static string DecryptAes(string source, string key)
{
using (AesCryptoServiceProvider aesProvider = new AesCryptoServiceProvider())
{
aesProvider.Key = GetAesKey(key);
aesProvider.Mode = CipherMode.ECB;
aesProvider.Padding = PaddingMode.PKCS7;
using (ICryptoTransform cryptoTransform = aesProvider.CreateDecryptor())
{
byte[] inputBuffers = Convert.FromBase64String(source);
byte[] results = cryptoTransform.TransformFinalBlock(inputBuffers, 0, inputBuffers.Length);
aesProvider.Clear();
return Encoding.UTF8.GetString(results);
}
}
}

#endregion