C#做的一個加密/解密的類

前兩年寫的東西，現在整理一下發出來！以前公司需要做WebService，並且對WebService的SoapHeader進行加密，所以就寫了這麼個東東！使用這個類，需要密鑰管理！為了保證資料的安全性往往要對資料進行加密，但是加密的缺點之一，就是影響程式的運行效率，所以，當時我的思路是只對使用者的登入資訊（使用者名稱，密碼）進行加密！資料用明文傳輸，使用者資訊驗證沒有通過的情況下, 不進行資料轉送。

實際在網路通訊中，使用密鑰匙的方式並非無懈可擊，如果駭客可以捕捉到用祕密金鑰加密的，使用者驗證資訊，然後，做個類比請求，向提供WebService的伺服器發請求，還是可以獲得請求資料！所以，我又使用了IP或者網域名稱綁定的方式！畢竟，WebService不是直接對終端使用者提供的！所以，加上以上這些手段後，就算有不良企圖者想通過非法方式獲得WebService提供的服務，就再費點勁吧！

還有一點安全建議，就是週期性更換密鑰，在這個例子中，我用的是對稱式加密，加密方和解密方的密鑰一致！週期性更換密鑰可以讓安全性提高一大截！

大家要有更好的方法，或者建議，可以留言討論一下！共同提高！

代碼如下：

using System;
using System.Security.Cryptography ;
using System.Text;
using System.IO;

namespace SEDO
{
/// <summary>
/// SEDO 的摘要說明。
/// SEDO 實現的是用一個封裝了4種對稱式加密方法(Des,Rc2,Rijndael,TripleDes)的組件
///
/// 注意事項：
/// 1:TripleDes和Rijndael加密/解密對象使用16或者24位byte的Key
/// 2:Rijndael只能使用16位的初始化向量IV
/// 3:Des和Rc2均使用8位Byte的Key和IV
/// 4:對需要加密/解密的資料流採用何種方法進行編碼/解碼，由調用組件的使用者自己決定
/// 5:密鑰和初始化向量IV由使用者自己定義
/// 程式員： 王海波 2003-05-19 hwnanghb@21cn.com
/// </summary>

//定義加密類型的枚舉
public enum EncryptionAlgorithm {Des = 1, Rc2, Rijndael, TripleDes};

//定義加密類
internal class EncryptTransformer
{
private EncryptionAlgorithm algorithmID;
private byte[] initVec;
private byte[] encKey;

internal EncryptTransformer(EncryptionAlgorithm algId)
{
//Save the algorithm being used.
algorithmID = algId;
}

internal ICryptoTransform GetCryptoServiceProvider(byte[] bytesKey)
{
//當資料密鑰Key或者初始化向量IV為空白的時候，將使用加密對象自動產生的密鑰Key或者初始化向量IV
switch (algorithmID)
{
case EncryptionAlgorithm.Des:
{
DES des = new DESCryptoServiceProvider();
des.Mode = CipherMode.CBC;

// See if a key was provided
if (null == bytesKey)
{
encKey = des.Key;
}
else
{
des.Key = bytesKey;
encKey = des.Key;
}
// See if the client provided an initialization vector
if (null == initVec)
{ // Have the algorithm create one
initVec = des.IV;
}
else
{ //No, give it to the algorithm
des.IV = initVec;
}
return des.CreateEncryptor();
}
case EncryptionAlgorithm.TripleDes:
{
TripleDES des3 = new TripleDESCryptoServiceProvider();
des3.Mode = CipherMode.CBC;
// See if a key was provided
if (null == bytesKey)
{
encKey = des3.Key;
}
else
{
des3.Key = bytesKey;
encKey = des3.Key;
}
// See if the client provided an IV
if (null == initVec)
{ //Yes, have the alg create one
initVec = des3.IV;
}
else
{ //No, give it to the alg.
des3.IV = initVec;
}
return des3.CreateEncryptor();
}
case EncryptionAlgorithm.Rc2:
{
RC2 rc2 = new RC2CryptoServiceProvider();
rc2.Mode = CipherMode.CBC;
// Test to see if a key was provided
if (null == bytesKey)
{
encKey = rc2.Key;
}
else
{
rc2.Key = bytesKey;
encKey = rc2.Key;
}
// See if the client provided an IV
if (null == initVec)
{ //Yes, have the alg create one
initVec = rc2.IV;
}
else
{ //No, give it to the alg.
rc2.IV = initVec;
}
return rc2.CreateEncryptor();
}
case EncryptionAlgorithm.Rijndael:
{
Rijndael rijndael = new RijndaelManaged();
rijndael.Mode = CipherMode.CBC;
// Test to see if a key was provided
if(null == bytesKey)
{
encKey = rijndael.Key;
}
else
{
rijndael.Key = bytesKey;
encKey = rijndael.Key;
}
// See if the client provided an IV
if(null == initVec)
{ //Yes, have the alg create one
initVec = rijndael.IV;
}
else
{ //No, give it to the alg.
rijndael.IV = initVec;
}
return rijndael.CreateEncryptor();
}
default:
{
throw new CryptographicException("Algorithm ID '" +
algorithmID +
"' not supported.");
}
}
}

//加密的位移向量
internal byte[] IV
{
get{return initVec;}
set{initVec = value;}
}
//加密的密鑰
internal byte[] Key
{
get{return encKey;}
set{encKey = value;}
}

}

//定義解密類
internal class DecryptTransformer
{
private EncryptionAlgorithm algorithmID;
private byte[] initVec;
private byte[] encKey;

internal DecryptTransformer(EncryptionAlgorithm deCryptId)
{
algorithmID = deCryptId;
}

//加密的位移向量
internal byte[] IV
{
get{return initVec;}
set{initVec = value;}
}

//加密的密鑰
internal byte[] Key
{
get{return encKey;}
set{encKey = value;}
}

internal ICryptoTransform GetCryptoServiceProvider(byte[] bytesKey)
{
//當資料密鑰Key或者初始化向量IV為空白的時候，將使用加密對象自動產生的密鑰Key或者初始化向量IV
switch (algorithmID)
{
case EncryptionAlgorithm.Des:
{
DES des = new DESCryptoServiceProvider();
des.Mode = CipherMode.CBC;
des.Key = bytesKey;
des.IV = initVec;
return des.CreateDecryptor();
}
case EncryptionAlgorithm.TripleDes:
{
TripleDES des3 = new TripleDESCryptoServiceProvider();
des3.Mode = CipherMode.CBC;
return des3.CreateDecryptor(bytesKey, initVec);
}
case EncryptionAlgorithm.Rc2:
{
RC2 rc2 = new RC2CryptoServiceProvider();
rc2.Mode = CipherMode.CBC;
return rc2.CreateDecryptor(bytesKey, initVec);
}
case EncryptionAlgorithm.Rijndael:
{
Rijndael rijndael = new RijndaelManaged();
rijndael.Mode = CipherMode.CBC;
return rijndael.CreateDecryptor(bytesKey, initVec);
}
default:
{
throw new CryptographicException("Algorithm ID '" +
algorithmID +
"' not supported.");
}
}
} //end GetCryptoServiceProvider

}

//定義加密者類
public class Encryptor
{
private EncryptTransformer transformer;
private byte[] initVec;
private byte[] encKey;

public Encryptor(EncryptionAlgorithm algId)
{
transformer = new EncryptTransformer(algId);
}

public byte[] Encrypt(byte[] bytesData, byte[] bytesKey,byte[] bytesIV)
{
//設定流對象用來儲存加密資料位元組流.
MemoryStream memStreamEncryptedData = new MemoryStream();

transformer.IV=bytesIV;
transformer.Key=bytesKey;

ICryptoTransform transform = transformer.GetCryptoServiceProvider(bytesKey);
CryptoStream encStream = new CryptoStream(memStreamEncryptedData,transform,CryptoStreamMode.Write);

try
{
//將加密資料寫進流對象
encStream.Write(bytesData, 0, bytesData.Length);
}
catch(Exception ex)
{
throw new Exception("在資料加密的時候出現錯誤！錯誤提示： \n" + ex.Message);
}

//設定加密的Key和初始向量IV屬性
encKey = transformer.Key;
initVec = transformer.IV;

encStream.FlushFinalBlock();
encStream.Close();

//Send the data back.
return memStreamEncryptedData.ToArray();
}

public byte[] IV
{
get{return initVec;}
set{initVec = value;}
}

public byte[] Key
{
get{return encKey;}
set{encKey = value;}
}

}

//定義解密者類
public class Decryptor
{
private DecryptTransformer transformer;
private byte[] initVec;
private byte[] encKey;

public Decryptor(EncryptionAlgorithm algId)
{
transformer = new DecryptTransformer(algId);
}

public byte[] Decrypt(byte[] bytesData, byte[] bytesKey,byte[] bytesIV)
{
//設定流對象用來儲存解密資料位元組流.
MemoryStream memStreamDecryptedData = new MemoryStream();

//Pass in the initialization vector.
transformer.IV = bytesIV;
transformer.Key = bytesKey;

ICryptoTransform transform = transformer.GetCryptoServiceProvider(bytesKey);
CryptoStream decStream = new CryptoStream(memStreamDecryptedData,transform, CryptoStreamMode.Write);

try
{
decStream.Write(bytesData, 0, bytesData.Length);
}
catch(Exception ex)
{
throw new Exception("在資料解密的時候出現錯誤！錯誤提示： \n" + ex.Message);
}
decStream.FlushFinalBlock();
decStream.Close();
// 返回解密資料.
return memStreamDecryptedData.ToArray();
}

public byte[] IV
{
get{return initVec;}
set{initVec = value;}
}

public byte[] Key
{
get{return encKey;}
set{encKey = value;}
}

}

//類描述：檔案加密/解密類
public class SecurityFile
{
private DecryptTransformer Dec_Transformer; //解密轉換器
private EncryptTransformer Enc_Transformer; //加密轉換器
private byte[] initVec;
private byte[] encKey;

public SecurityFile(EncryptionAlgorithm algId)
{
Dec_Transformer = new DecryptTransformer(algId);
Enc_Transformer = new EncryptTransformer(algId);
}

//加密的位移向量
internal byte[] IV
{
get{return initVec;}
set{initVec = value;}
}
//加密的密鑰
internal byte[] Key
{
get{return encKey;}
set{encKey = value;}
}

//功能描述：加密檔案
public void EncryptFile(string inFileName, string outFileName, byte[] bytesKey, byte[] bytesIV)
{
try
{
FileStream fin = new FileStream(inFileName, FileMode.Open, FileAccess.Read);
FileStream fout = new FileStream(outFileName, FileMode.OpenOrCreate, FileAccess.Write);
fout.SetLength(0);

//Create variables to help with read and write.
byte[] bin = new byte[100]; //This is intermediate storage for the encryption.
long rdlen = 0; //This is the total number of bytes written.
long totlen = fin.Length; //This is the total length of the input file.
int len; //This is the number of bytes to be written at a time.

Enc_Transformer.IV=bytesIV;
Enc_Transformer.Key=bytesKey;

ICryptoTransform transform = Enc_Transformer.GetCryptoServiceProvider(bytesKey);
CryptoStream encStream = new CryptoStream(fout, transform, CryptoStreamMode.Write);

//Read from the input file, then encrypt and write to the output file.
while(rdlen < totlen)
{
len = fin.Read(bin, 0, 100);
encStream.Write(bin, 0, len);
rdlen = rdlen + len;
}

encStream.Close();
fout.Close();
fin.Close();
}
catch(Exception ex)
{
throw new Exception("在檔案加密的時候出現錯誤！錯誤提示： \n" + ex.Message);
}
}

//功能描述：解密檔案
public void DecryptFile(string inFileName, string outFileName, byte[] bytesKey, byte[] bytesIV)
{
try
{
FileStream fin = new FileStream(inFileName, FileMode.Open, FileAccess.Read);
FileStream fout = new FileStream(outFileName, FileMode.OpenOrCreate, FileAccess.Write);
fout.SetLength(0);

//Create variables to help with read and write.
byte[] bin = new byte[100]; //This is intermediate storage for the encryption.
long rdlen = 0; //This is the total number of bytes written.
long totlen = fin.Length; //This is the total length of the input file.
int len; //This is the number of bytes to be written at a time.

Dec_Transformer.IV=bytesIV;
Dec_Transformer.Key=bytesKey;

ICryptoTransform transform = Dec_Transformer.GetCryptoServiceProvider(bytesKey);
CryptoStream encStream = new CryptoStream(fout, transform, CryptoStreamMode.Write);

//Read from the input file, then encrypt and write to the output file.
while(rdlen < totlen)
{
len = fin.Read(bin, 0, 100);
encStream.Write(bin, 0, len);
rdlen = rdlen + len;
}

encStream.Close();
fout.Close();
fin.Close();
}
catch(Exception ex)
{
throw new Exception("在檔案加密的時候出現錯誤！錯誤提示： \n" + ex.Message);
}
}

}

}