DotNet中几种常用的加密算法

      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string
                var 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。