在.NET项目中，我们较多的使用到加密这个操作。因为在现代的项目中，对信息安全的要求越来越高，那么多信息的加密就变得至关重要。现在提供几种常用的加密/解密算法。

1.用于文本和Base64编码文本的互相转换 和 Byte[]和Base64编码文本的互相转换：

(1).将普通文本转换成Base64编码的文本

        /// <summary>/// 将普通文本转换成Base64编码的文本/// </summary>/// <param name="value">普通文本</param>/// <returns></returns>public static string StringToBase64String(string value){if (string.IsNullOrEmpty(value)){throw new ArgumentNullException(value);}try{var binBuffer = (new UnicodeEncoding()).GetBytes(value);var base64ArraySize = (int)Math.Ceiling(binBuffer.Length / 3d) * 4;var charBuffer = new char[base64ArraySize];Convert.ToBase64CharArray(binBuffer, 0, binBuffer.Length, charBuffer, 0);var s = new string(charBuffer);return s;}catch (Exception ex){throw new Exception(ex.Message);}}

(2).将Base64编码的文本转换成普通文本

        /// <summary>/// 将Base64编码的文本转换成普通文本/// </summary>/// <param name="base64">Base64编码的文本</param>/// <returns></returns>public static string Base64StringToString(string base64){if (string.IsNullOrEmpty(base64)){throw new ArgumentNullException(base64);}try{var charBuffer = base64.ToCharArray();var bytes = Convert.FromBase64CharArray(charBuffer, 0, charBuffer.Length);return (new UnicodeEncoding()).GetString(bytes);}catch (Exception ex){throw new Exception(ex.Message);}}

(3).将Byte[]转换成Base64编码文本

        /// <summary>/// 将Byte[]转换成Base64编码文本/// </summary>/// <param name="binBuffer">Byte[]</param>/// <returns></returns>public string ToBase64(byte[] binBuffer){if (binBuffer == null){throw new ArgumentNullException("binBuffer");}try{var base64ArraySize = (int)Math.Ceiling(binBuffer.Length / 3d) * 4;var charBuffer = new char[base64ArraySize];Convert.ToBase64CharArray(binBuffer, 0, binBuffer.Length, charBuffer, 0);var s = new string(charBuffer);return s;}catch (Exception ex){throw new Exception(ex.Message);}}

(4).将Base64编码文本转换成Byte[]

        /// <summary>/// 将Base64编码文本转换成Byte[]/// </summary>/// <param name="base64">Base64编码文本</param>/// <returns></returns>public byte[] Base64ToBytes(string base64){if (string.IsNullOrEmpty(base64)){throw new ArgumentNullException(base64);}try{var charBuffer = base64.ToCharArray();var bytes = Convert.FromBase64CharArray(charBuffer, 0, charBuffer.Length);return bytes;}catch (Exception ex){throw new Exception(ex.Message);}}

2. DES加密/解密类。

(1).加密

private static readonly string KEY = "pengze0902";/// <summary>/// 加密/// </summary>/// <param name="Text"></param>/// <returns></returns>public static string Encrypt(string Text){return Encrypt(Text, KEY);}/// <summary> /// 加密数据 /// </summary> /// <param name="Text"></param> /// <param name="sKey"></param> /// <returns></returns> public static string Encrypt(string Text, string sKey){var des = new DESCryptoServiceProvider();var inputByteArray = Encoding.Default.GetBytes(Text);var bKey = Encoding.ASCII.GetBytes(Md5Hash(sKey).Substring(0, 8));des.Key = bKey;des.IV = bKey;var ms = new System.IO.MemoryStream();var cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);cs.Write(inputByteArray, 0, inputByteArray.Length);cs.FlushFinalBlock();var ret = new StringBuilder();foreach (byte b in ms.ToArray()){ret.AppendFormat("{0:X2}", b);}return ret.ToString();}

(2).解密

private static readonly string KEY = "pengze0902";/// <summary>/// 解密/// </summary>/// <param name="text"></param>/// <returns></returns>public static string Decrypt(string text){return Decrypt(text, KEY);}/// <summary> /// 解密数据 /// </summary> /// <param name="text"></param> /// <param name="sKey"></param> /// <returns></returns> public static string Decrypt(string text, string sKey){var des = new DESCryptoServiceProvider();var len = text.Length / 2;byte[] inputByteArray = new byte[len];int x;for (x = 0; x < len; x++){var i = Convert.ToInt32(text.Substring(x * 2, 2), 16);inputByteArray[x] = (byte)i;}var bKey = Encoding.ASCII.GetBytes(Md5Hash(sKey).Substring(0, 8));des.Key = bKey;des.IV = bKey;System.IO.MemoryStream ms = new System.IO.MemoryStream();CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);cs.Write(inputByteArray, 0, inputByteArray.Length);cs.FlushFinalBlock();return Encoding.Default.GetString(ms.ToArray());}

(3).取得MD5加密串

         <summary>/// 取得MD5加密串/// </summary>/// <param name="input">源明文字符串</param>/// <returns>密文字符串</returns>public static string Md5Hash(string input){var md5 = new MD5CryptoServiceProvider();var bs = Encoding.UTF8.GetBytes(input);bs = md5.ComputeHash(bs);var s = new StringBuilder();foreach (var b in bs){s.Append(b.ToString("x2").ToUpper());}var password = s.ToString();return password;}

3.MD5加密

(1). 32位大写

        /// <summary>/// 32位大写/// </summary>/// <returns></returns>public static string Upper32(string s){var hashPasswordForStoringInConfigFile = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(s, "md5");if (hashPasswordForStoringInConfigFile != null)s = hashPasswordForStoringInConfigFile.ToString();return s.ToUpper();}

(2). 32位小写

        /// <summary>/// 32位小写/// </summary>/// <returns></returns>public static string Lower32(string s){var hashPasswordForStoringInConfigFile = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(s, "md5");if (hashPasswordForStoringInConfigFile != null)s = hashPasswordForStoringInConfigFile.ToString();return s.ToLower();}

(3).16位大写

         /// <summary>/// 16位大写/// </summary>/// <returns></returns>public static string Upper16(string s){var hashPasswordForStoringInConfigFile = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(s, "md5");if (hashPasswordForStoringInConfigFile != null)s = hashPasswordForStoringInConfigFile.ToString();return s.ToUpper().Substring(8, 16);}

(4).16位小写

        /// <summary>/// 16位小写/// </summary>/// <returns></returns>public static string Lower16(string s){var hashPasswordForStoringInConfigFile = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(s, "md5");if (hashPasswordForStoringInConfigFile != null)s = hashPasswordForStoringInConfigFile.ToString();return s.ToLower().Substring(8, 16);}

4.Sha1签名算法

        /// <summary>/// 签名算法/// </summary>/// <param name="str"></param>/// <returns></returns>public static string GetSha1(string str){if (string.IsNullOrEmpty(str)){throw new ArgumentNullException(str);}try{//建立SHA1对象SHA1 sha = new SHA1CryptoServiceProvider();//将mystr转换成byte[] var enc = new ASCIIEncoding();var dataToHash = enc.GetBytes(str);//Hash运算var dataHashed = sha.ComputeHash(dataToHash);//将运算结果转换成stringvar hash = BitConverter.ToString(dataHashed).Replace("-", "");return hash;}catch (Exception ex){throw new Exception(ex.Message);}}

5.Sha256加密算法

        /// <summary>/// 将字符串转换为sha256散列/// </summary>/// <param name="data">字符串进行转换</param>/// <returns>sha256散列或null</returns>public static string ToSha256(this string data){try{if (string.IsNullOrEmpty(data))return null;var hashValue = new SHA256Managed().ComputeHash(Encoding.UTF8.GetBytes(data));var hex = hashValue.Aggregate("", (current, x) => current + String.Format("{0:x2}", x));if (string.IsNullOrEmpty(hex))throw new Exception("Erro creating SHA256 hash");return hex;}catch (Exception e){throw new Exception(e.Message, e);}}

以上是一些较为常用的算法代码。