public static class EncryptionHelper
{
#region const
/// <summary>
/// 默认使用的适合于DES,RC2算法的Key
/// </summary>
private const string m_ShortDefaultKey = "Nesc";
/// <summary>
/// 默认使用的TRIPLEDES，RIJNDAEL算法的Key
/// </summary>
private const string m_LongDefaultKey = "Nesc.Oversea";
/// <summary>
/// 默认使用的适合于DES,RC2,TRIPLEDES算法的InitVector
/// </summary>
private const string m_ShortDefaultIV = ""; /// <summary>
/// 默认使用的适合于RIJNDAEL算法的InitVector
/// </summary>
private const string m_LongDefaultIV = "Oversea3"; #endregion
private static byte[] m_Key = null; private static byte[] m_initVec = null; #region properties
/// <summary>
/// 使用的加密明文密码
/// </summary>
public static string Key
{
get
{
string result = string.Empty;
if (m_Key != null)
{
result = Encoding.Unicode.GetString(m_Key);
}
return result;
} }
/// <summary>
/// 使用加密的起始偏移量
/// </summary>
public static string InitVector
{
get
{
string result = string.Empty;
if (m_initVec != null)
{
result = Encoding.Unicode.GetString(m_initVec);
}
return result;
} }
#endregion /// <summary>
/// 接受用户明文密码，本次加密使用的算法，完成对指定字符串的加密
/// <example><![CDATA[string result = EncryptionHelper.Encrypt("1234", EncryptionAlgorithm.Rc2, "5678", text);]]></example>
/// <remarks>各个算法对明文密码和初始化偏移量的要求不一样
/// DES和RC2:明文密码长度和初始化偏移量长度 必须是4个字符;
/// Rijndael:明文密码长度可以是12,16个字符,初始化偏移量为8个字符;
/// TripleDes:明文密码长度可以为8个和12个字符,初始化偏移量为4个字符;
/// 注意:如果提供的明文密码和偏移量不符合算法的标准,将使用随机密码,使用者在加密后通过提供的Key和InitVector属性获得加密时使用的明文密码和偏移量
/// </remarks>
/// </summary>
/// <param name="plainText">使用的加密明文密码</param>
/// <param name="algorithm">加密算法枚举对象</param>
/// <param name="userInitialVector">使用的加密起始偏移量</param>
/// <param name="encryptionText">需要加密的字符</param>
/// <returns></returns>
public static string Encrypt(string plainText, EncryptionAlgorithm algorithm, string userInitialVector, string encryptionText)
{
string result = string.Empty; if (encryptionText.Length > )
{
SetKey(algorithm, plainText);
SetInitialVector(algorithm, userInitialVector);
EncryptTransform transform = new EncryptTransform(m_Key,m_initVec);
byte[] bytes = Encoding.Unicode.GetBytes(encryptionText);
byte[] inArray = transform.Encrypt(algorithm, bytes);
if (inArray.Length > )
{
result = Convert.ToBase64String(inArray);
}
m_Key = transform.Key;
m_initVec = transform.InitVec; }
return result; } /// <summary>
/// 指定需要加密的字符串使用默认的明文密码和算法(DES)进行加密
/// </summary>
/// <param name="encryptionText"></param>
/// <returns></returns>
public static string Encrypt(string encryptionText)
{
string result = string.Empty;
result = Encrypt(m_ShortDefaultKey, EncryptionAlgorithm.Des, m_ShortDefaultIV, encryptionText);
return result;
}
/// <summary>
/// 指定需要加密的字符串和算法使用默认的明文密码进行加密
/// </summary>
/// <param name="algorithm"></param>
/// <param name="encryptionText"></param>
/// <returns></returns>
public static string Encrypt(EncryptionAlgorithm algorithm, string encryptionText)
{
string result = string.Empty;
string key = GetDefaultKey(algorithm);
string iv = GetDefaultIV(algorithm);
result = Encrypt(key, algorithm, iv, encryptionText);
return result;
} /// <summary>
/// 接受用户明文密码，使用默认的加密算法完成对指定字符串的加密
/// <remarks>默认为DES算法进行加密</remarks>
/// <example><![CDATA[string result = EncryptionHelper.Encrypt("1234", "5678", text);]]></example>
/// </summary>
/// <param name="plainText">使用的加密明文密码</param>
/// <param name="userInitialVector">使用的加密起始偏移量</param>
/// <param name="encryptionText">需要加密的字符串</param>
/// <returns>加密后的字符串</returns>
public static string Encrypt(string plainText, string userInitialVector, string encryptionText)
{
string result = string.Empty;
result = Encrypt(plainText, EncryptionAlgorithm.Des, userInitialVector, encryptionText);
return result;
} /// <summary>
/// 接受用户明文密码，本次使用的解密算法，完成对指定字符串的解密；
/// <remarks>指定的解密算法必须和字符串使用加密的算法一致
/// 各个算法对明文密码和初始化偏移量的要求不一样
/// DES和RC2:明文密码长度和初始化偏移量长度 必须是4个字符;
/// Rijndael:明文密码长度可以是12,16个字符,初始化偏移量为8个字符;
/// TripleDes:明文密码长度可以为8个和12个字符,初始化偏移量为4个字符;
/// </summary>
/// <param name="plainText">加密明文密码</param>
/// <param name="algorithm">使用的加密算法</param>
/// <param name="userInitialVector">加密时使用的起始偏移量</param>
/// <param name="encryptionText">加密后的字符串</param>
/// <returns></returns>
public static string Decrypt(string plainText, EncryptionAlgorithm algorithm, string userInitialVector, string encryptionText)
{
string result = string.Empty;
SetKey(algorithm, plainText);
SetInitialVector(algorithm, userInitialVector);
EncryptTransform transform = new EncryptTransform(m_Key, m_initVec);
byte[] bytesData = Convert.FromBase64String(encryptionText);
byte[] bytes = null;
try
{
bytes = transform.Decrypt(algorithm, bytesData);
}
catch (Exception exception)
{
throw exception;
}
if (bytes.Length > )
{
result = Encoding.Unicode.GetString(bytes);
}
m_Key = transform.Key;
m_initVec = transform.InitVec;
return result; } /// <summary>
/// 接受用户明文密码，使用默认解密算法完成对指定字符串的解密
/// </summary>
/// <param name="plainText">加密时使用的明文密码</param>
/// <param name="userInitialVector">加密时使用的起始偏移量</param>
/// <param name="encryptionText">加密后的字符串</param>
/// <returns></returns>
public static string Decrypt(string plainText, string userInitialVector, string encryptionText)
{
string result = string.Empty;
result=Decrypt(plainText, EncryptionAlgorithm.Des,userInitialVector,encryptionText);
return result; } /// <summary>
/// 使用默认的算法(DES)和默认的明文密码进行解密
/// </summary>
/// <param name="encryptionText"></param>
/// <returns></returns>
public static string Decrypt(string encryptionText)
{
string result = string.Empty;
result = Decrypt(m_ShortDefaultKey, EncryptionAlgorithm.Des, m_ShortDefaultIV, encryptionText);
return result; }
/// <summary>
/// 指定加密时使用的算法,使用默认的明文密码进行解密
/// </summary>
/// <param name="algorithm"></param>
/// <param name="encryptionText"></param>
/// <returns></returns>
public static string Decrypt(EncryptionAlgorithm algorithm,string encryptionText)
{
string result = string.Empty;
string key = GetDefaultKey(algorithm);
string iv = GetDefaultIV(algorithm);
result = Decrypt(key, algorithm, iv, encryptionText);
return result; } /// <summary>
/// 根据算法获得默认的Key
/// </summary>
/// <param name="algorithm"></param>
/// <returns></returns>
private static string GetDefaultKey(EncryptionAlgorithm algorithm)
{
string result = m_ShortDefaultKey;
switch (algorithm)
{
case EncryptionAlgorithm.Rijndael:
{
result = m_LongDefaultKey;
break;
}
case EncryptionAlgorithm.TripleDes:
{
result = m_LongDefaultKey;
break;
}
}
return result;
}
/// <summary>
/// 根据算法获得默认的IV
/// </summary>
/// <param name="algorithm"></param>
/// <returns></returns>
private static string GetDefaultIV(EncryptionAlgorithm algorithm)
{
string result = m_ShortDefaultIV;
switch (algorithm)
{
case EncryptionAlgorithm.Rijndael:
{
result = m_LongDefaultIV;
break;
}
}
return result;
} /// <summary>
///
/// </summary>
/// <param name="algorithm"></param>
/// <param name="initialVector"></param>
/// <returns></returns>
private static void SetInitialVector(EncryptionAlgorithm algorithm, string initialVector)
{
if (null != initialVector)
{
byte[] bytes = Encoding.Unicode.GetBytes(initialVector);
switch (algorithm)
{
case EncryptionAlgorithm.Des:
{
if ( bytes.Length == )
{
m_initVec = bytes; }
break;
} case EncryptionAlgorithm.Rc2:
{
if ( bytes.Length == )
{
m_initVec = bytes; }
break;
}
case EncryptionAlgorithm.Rijndael:
{
if ( bytes.Length ==)
{
m_initVec = bytes; }
break;
}
case EncryptionAlgorithm.TripleDes:
{
if (bytes.Length == )
{
m_initVec = bytes; }
break;
}
}
}
} private static void SetKey(EncryptionAlgorithm algorithm, string key)
{
if (null != key)
{
byte[] keyByte = Encoding.Unicode.GetBytes(key);
switch (algorithm)
{
case EncryptionAlgorithm.Des:
{
if (keyByte.Length== )
{
m_Key = keyByte;
}
break;
} case EncryptionAlgorithm.Rc2:
{
if (keyByte.Length == )
{
m_Key = keyByte;
}
break;
}
case EncryptionAlgorithm.Rijndael:
{
if (keyByte.Length== || (keyByte.Length == ))
{
m_Key = keyByte;
}
break;
}
case EncryptionAlgorithm.TripleDes:
{
if (keyByte.Length == ||(keyByte.Length == ))
{
m_Key = keyByte;
}
break;
}
}
}
} }