这篇文章主要介绍了C#常用字符串加密解密方法封装代码，有需要的朋友可以参考一下
代码如下://方法一//须添加对System.Web的引用//using System.Web.Security;/// <summary>/// SHA1加密字符串/// </summary>/// <param name="source">源字符串</param>/// <returns>加密后的字符串</returns>public string SHA1(string source){ return FormsAuthentication.HashPasswordForStoringInConfigFile(source, "SHA1");}/// <summary>/// MD5加密字符串/// </summary>/// <param name="source">源字符串</param>/// <returns>加密后的字符串</returns>public string MD5(string source){ return FormsAuthentication.HashPasswordForStoringInConfigFile(source, "MD5");;}//方法二(可逆加密解密)：//using System.Security.Cryptography;public string Encode(string data){ byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64); byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64); DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider(); int i = cryptoProvider.KeySize; MemoryStream ms = new MemoryStream(); CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write); StreamWriter sw = new StreamWriter(cst); sw.Write(data); sw.Flush(); cst.FlushFinalBlock(); sw.Flush(); return Convert.Tobase64String(ms.GetBuffer(), 0, (int)ms.Length);}public string Decode(string data){ byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64); byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64); byte[] byEnc; try { byEnc = Convert.Frombase64String(data); } catch { return null; } DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider(); MemoryStream ms = new MemoryStream(byEnc); CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read); StreamReader sr = new StreamReader(cst);//方法三(MD5不可逆)：//using System.Security.Cryptography;//MD5不可逆加密//32位加密public string GetMD5_32(string s, string _input_charset){ MD5 md5 = new MD5CryptoServiceProvider(); byte[] t = md5.ComputeHash(Encoding.GetEncoding(_input_charset).GetBytes(s)); StringBuilder sb = new StringBuilder(32); for (int i = 0; i < t.Length; i++) { sb.Append(t[i].ToString("x").PadLeft(2, '0')); } return sb.ToString();}//16位加密public static string GetMd5_16(string ConvertString){ MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider(); string t2 = BitConverter.ToString(md5.ComputeHash(UTF8Encoding.Default.GetBytes(ConvertString)), 4, 8); t2 = t2.Replace("-", ""); return t2;}//方法四(对称加密)：//using System.IO;//using System.Security.Cryptography;private SymmetricAlgorithm mobjCryptoService;private string Key;/// <summary> /// 对称加密类的构造函数 /// </summary> public SymmetricMethod(){ mobjCryptoService = new RijndaelManaged(); Key = "Guz(%&hj7x89H$yuBI0456FtmaT5&fvHUFCy76*h%(HilJ$lhj!y6&(*jkP87jH7";}/// <summary> /// 获得密钥 /// </summary> /// <returns>密钥</returns> private byte[] GetLegalKey(){ string sTemp = Key; mobjCryptoService.GenerateKey(); byte[] bytTemp = mobjCryptoService.Key; int KeyLength = bytTemp.Length; if (sTemp.Length > KeyLength) sTemp = sTemp.Substring(0, KeyLength); else if (sTemp.Length < KeyLength) sTemp = sTemp.PadRight(KeyLength, ' '); return ASCIIEncoding.ASCII.GetBytes(sTemp);}/// <summary> /// 获得初始向量IV /// </summary> /// <returns>初试向量IV</returns> private byte[] GetLegalIV(){ string sTemp = "E4ghj*Ghg7!rNIfb&95GUY86GfghUb#er57HBh(u%g6HJ($jhWk7&!hg4ui%$hjk"; mobjCryptoService.GenerateIV(); byte[] bytTemp = mobjCryptoService.IV; int IVLength = bytTemp.Length; if (sTemp.Length > IVLength) sTemp = sTemp.Substring(0, IVLength); else if (sTemp.Length < IVLength) sTemp = sTemp.PadRight(IVLength, ' '); return ASCIIEncoding.ASCII.GetBytes(sTemp);}/// <summary> /// 加密方法 /// </summary> /// <param name="Source">待加密的串</param> /// <returns>经过加密的串</returns> public string Encrypto(string Source){ byte[] bytIn = UTF8Encoding.UTF8.GetBytes(Source); MemoryStream ms = new MemoryStream(); mobjCryptoService.Key = GetLegalKey(); mobjCryptoService.IV = GetLegalIV(); ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor(); CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write); cs.Write(bytIn, 0, bytIn.Length); cs.FlushFinalBlock(); ms.Close(); byte[] bytOut = ms.ToArray(); return Convert.Tobase64String(bytOut);}/// <summary> /// 解密方法 /// </summary> /// <param name="Source">待解密的串</param> /// <returns>经过解密的串</returns> public string Decrypto(string Source){ byte[] bytIn = Convert.Frombase64String(Source); MemoryStream ms = new MemoryStream(bytIn, 0, bytIn.Length); mobjCryptoService.Key = GetLegalKey(); mobjCryptoService.IV = GetLegalIV(); ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor(); CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read); StreamReader sr = new StreamReader(cs); return sr.ReadToEnd();}//方法五：//using System.IO;//using System.Security.Cryptography;//using System.Text;//默认密钥向量private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };/// <summary>/// DES加密字符串 keleyi.com/// </summary>/// <param name="encryptString">待加密的字符串</param>/// <param name="encryptKey">加密密钥,要求为8位</param>/// <returns>加密成功返回加密后的字符串，失败返回源串</returns>public static string EncryptDES(string encryptString, string encryptKey){ try { byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8)); byte[] rgbIV = Keys; byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString); DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider(); MemoryStream mStream = new MemoryStream(); CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write); cStream.Write(inputByteArray, 0, inputByteArray.Length); cStream.FlushFinalBlock(); return Convert.Tobase64String(mStream.ToArray()); } catch { return encryptString; }}/// <summary>/// DES解密字符串 keleyi.com/// </summary>/// <param name="decryptString">待解密的字符串</param>/// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>/// <returns>解密成功返回解密后的字符串，失败返源串</returns>public static string DecryptDES(string decryptString, string decryptKey){ try { byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey); byte[] rgbIV = Keys; byte[] inputByteArray = Convert.Frombase64String(decryptString); DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider(); MemoryStream mStream = new MemoryStream(); CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write); cStream.Write(inputByteArray, 0, inputByteArray.Length); cStream.FlushFinalBlock(); return Encoding.UTF8.GetString(mStream.ToArray()); } catch { return decryptString; }}//方法六(文件加密)：//using System.IO;//using System.Security.Cryptography;//using System.Text;//加密文件private static void EncryptData(String inName, String outName, byte[] desKey, byte[] desIV){ //Create the file streams to handle the input and output files. FileStream fin = new FileStream(inName, FileMode.Open, FileAccess.Read); FileStream fout = new FileStream(outName, 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(desKey, desIV), 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();}//解密文件private static void DecryptData(String inName, String outName, byte[] desKey, byte[] desIV){ //Create the file streams to handle the input and output files. FileStream fin = new FileStream(inName, FileMode.Open, FileAccess.Read); FileStream fout = new FileStream(outName, 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(desKey, desIV), 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(); return sr.ReadToEnd();}详细出处参考：http://www.jb51.net/article/44133.htm
