使用Des，MD5加密解密字符串文件

//加密字符串,注意strEncrKey的长度为8位(如果要增加或者减少key长度,调整IV的长度就是了)
 public string DesEncrypt(string strText, string strEncrKey) //解密字符串,注意strEncrKey的长度为8位(如果要增加或者减少key长度,调整IV的长度就是了)
public string DesDecrypt(string strText,string sDecrKey)
//加密数据文件,注意strEncrKey的长度为8位(如果要增加或者减少key长度,调整IV的长度就是了)
public void DesEncrypt(string m_InFilePath,string m_OutFilePath,string strEncrKey)
//解密数据文件,注意strEncrKey的长度为8位(如果要增加或者减少key长度,调整IV的长度就是了)
public void DesDecrypt(string m_InFilePath,string m_OutFilePath,string sDecrKey)
//MD5加密
public string MD5Encrypt(string strText)
*/
/******************************************************************************************
 * Cryptography class is for Cryptography
 author:Jim
 e_mail:[e-mail] 
 * thanks:
 * URI:
 * 
 * 
 *****************************************************************************************/
 using System;
 using System.Security.Cryptography;
 using System.Text;
 using System.IO;
 using System.Windows.Forms ;namespace Netbee.Classes.Security
 {
 /// <summary>
 ///Cryptography
 /// </summary>
 public class Cryptography
 {
 public Cryptography()
 {}
 /// <summary>
 /// Encrypt the string
 /// Attention:key must be 8 bits
 /// </summary>
 /// <param name="strText">string</param>
 /// <param name="strEncrKey">key</param>
 /// <returns></returns>
 public string DesEncrypt(string strText, string strEncrKey)
 {
 byte[] byKey=null; 
 byte[] IV= {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF};
 try
 {
 byKey = System.Text.Encoding.UTF8.GetBytes(strEncrKey.Substring(0,8));
 DESCryptoServiceProvider des = new DESCryptoServiceProvider();
 byte[] inputByteArray = Encoding.UTF8.GetBytes(strText);
 MemoryStream ms = new MemoryStream();
 CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(byKey, IV), CryptoStreamMode.Write) ;
 cs.Write(inputByteArray, 0, inputByteArray.Length);
 cs.FlushFinalBlock();
 return Convert.ToBase64String(ms.ToArray()); }
 catch(System.Exception error)
 {
 MessageBox.Show(error.Message);
 return "error:" +error.Message+"\r";
 }
 }
 /// <summary>
 /// Decrypt string
 /// Attention:key must be 8 bits
 /// </summary>
 /// <param name="strText">Decrypt string</param>
 /// <param name="sDecrKey">key</param>
 /// <returns>output string</returns>
 public string DesDecrypt(string strText,string sDecrKey)
 {
 byte[] byKey = null; 
 byte[] IV= {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF}; 
 byte[] inputByteArray = new Byte[strText.Length];
 try
 {
 byKey = System.Text.Encoding.UTF8.GetBytes(sDecrKey.Substring(0,8));
 DESCryptoServiceProvider des = new DESCryptoServiceProvider();
 inputByteArray = Convert.FromBase64String(strText);
 MemoryStream ms = new MemoryStream();
 CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write);
 cs.Write(inputByteArray, 0, inputByteArray.Length);
 cs.FlushFinalBlock();
 System.Text.Encoding encoding = new System.Text.UTF8Encoding();
 return encoding.GetString(ms.ToArray());
 }
 catch(System.Exception error)
 {
 MessageBox.Show(error.Message);
 return "error:"+error.Message+"\r";
 }
 }
 /// <summary>
 /// Encrypt files
 /// Attention:key must be 8 bits
 /// </summary>
 /// <param name="m_InFilePath">Encrypt file path</param>
 /// <param name="m_OutFilePath">output file</param>
 /// <param name="strEncrKey">key</param>
 public void DesEncrypt(string m_InFilePath,string m_OutFilePath,string strEncrKey)
 {
 byte[] byKey=null; 
 byte[] IV= {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF};
 try
 {
 byKey = System.Text.Encoding.UTF8.GetBytes(strEncrKey.Substring(0,8));
 FileStream fin = new FileStream(m_InFilePath, FileMode.Open, FileAccess.Read);
 FileStream fout = new FileStream(m_OutFilePath, 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.DES des = new DESCryptoServiceProvider(); 
 CryptoStream encStream = new CryptoStream(fout, des.CreateEncryptor(byKey, IV), 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(System.Exception error)
 {
 MessageBox.Show(error.Message.ToString());}
 }
 /// <summary>
 /// Decrypt files
 /// Attention:key must be 8 bits
 /// </summary>
 /// <param name="m_InFilePath">Decrypt filepath</param>
 /// <param name="m_OutFilePath">output filepath</param>
 /// <param name="sDecrKey">key</param>
 public void DesDecrypt(string m_InFilePath,string m_OutFilePath,string sDecrKey)
 {
 byte[] byKey = null; 
 byte[] IV= {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF}; 
 try
 {
 byKey = System.Text.Encoding.UTF8.GetBytes(sDecrKey.Substring(0,8)); 
 FileStream fin = new FileStream(m_InFilePath, FileMode.Open, FileAccess.Read);
 FileStream fout = new FileStream(m_OutFilePath, 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.DES des = new DESCryptoServiceProvider(); 
 CryptoStream encStream = new CryptoStream(fout, des.CreateDecryptor(byKey, IV), 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(System.Exception error)
 {
 MessageBox.Show( "error:"+error.Message);
 }
 }
 /// <summary>
 /// MD5 Encrypt
 /// </summary>
 /// <param name="strText">text</param>
 /// <returns>md5 Encrypt string</returns>
 public string MD5Encrypt(string strText)
 {
 MD5 md5 = new MD5CryptoServiceProvider();
 byte[] result = md5.ComputeHash(System.Text.Encoding.Default.GetBytes(strText)); 
 return System.Text.Encoding.Default.GetString(result);
 }
 }
 }