Unity开发中常用的加密算法 MD5，Sha1、CRC32，Des，Res等的实现

public class EncryptUtil    {        #region MD5        public static string MD5Encrypt(string str, int length = 32)        {            if (string.IsNullOrEmpty(str))                return string.Empty;            byte[] result = Encoding.UTF8.GetBytes(str);            MD5 md5 = MD5.Create();            byte[] output = md5.ComputeHash(result);            return HandlBytes(output, length);        }        public static string AbstractFileMD5(string fileName, int length = 32)        {            if (string.IsNullOrEmpty(fileName))                return string.Empty;            using (FileStream file = new FileStream(fileName, FileMode.Open))            {                MD5 md5 = MD5.Create();                byte[] retVal = md5.ComputeHash(file);                return HandlBytes(retVal, length);            }        }        public static string HandlBytes(byte[] intput, int length = 32)        {            string md5Str = string.Empty;            switch (length)            {                case 16:                    md5Str = BitConverter.ToString(intput, 4, 8);                    break;                default:                    md5Str = BitConverter.ToString(intput);                    break;            }            return md5Str.Replace("-", "");        }        #endregion        #region Sha1        public static string AbstractFileSha1(string fileName)        {            if (string.IsNullOrEmpty(fileName))                return string.Empty;            using (FileStream file = new FileStream(fileName, FileMode.Open))            {                SHA1 md5 = SHA1.Create();                byte[] retVal = md5.ComputeHash(file);                return HandlBytes(retVal);            }        }        public static string EncryptSha1(string str)        {            if (string.IsNullOrEmpty(str))                return string.Empty;            var buffer = Encoding.UTF8.GetBytes(str);            var output = SHA1.Create().ComputeHash(buffer);            return HandlBytes(output);        }        #endregion        #region CRC32        public static string AbstractFileCRC32(string fileName)        {            if (string.IsNullOrEmpty(fileName))                return string.Empty;            var buffer = File.ReadAllBytes(fileName);            var output = CRC32.Create().ComputeHash(buffer);            return string.Format("{0:X8}", output);        }        public static string EncryptCRC32(string str)        {            if (string.IsNullOrEmpty(str))                return string.Empty;            var buffer = Encoding.UTF8.GetBytes(str);            var output = CRC32.Create().ComputeHash(buffer);            return string.Format("{0:X8}", output);        }        class CRC32        {            protected ulong[] Crc32Table;            private CRC32()            {                //生成码表                GetCRC32Table();            }            //生成CRC32码表            public void GetCRC32Table()            {                ulong Crc;                Crc32Table = new ulong[256];                int i, j;                for (i = 0; i < 256; i++)                {                    Crc = (ulong)i;                    for (j = 8; j > 0; j--)                    {                        if ((Crc & 1) == 1)                            Crc = (Crc >> 1) ^ 0xEDB88320;                        else                            Crc >>= 1;                    }                    Crc32Table[i] = Crc;                }            }            //获取字符串的CRC32校验值            public ulong ComputeHash(byte[] buffer)            {                ulong value = 0xffffffff;                int len = buffer.Length;                for (int i = 0; i < len; i++)                {                    value = (value >> 8) ^ Crc32Table[(value & 0xFF) ^ buffer[i]];                }                return value ^ 0xffffffff;            }            public static CRC32 Create()            {                return new CRC32();            }        }        #endregion        #region Des加密        private static void HandlDesStr(ref string key)        {            if (key.Length >= 8)            {                key = key.Substring(0, 8);            }            else            {                StringBuilder sb = new StringBuilder();                sb.Append(key);                for (int i = 0; i < 8 - key.Length; i++)                {                    sb.Append("#");                }                key = sb.ToString();            }        }        /// 
        ///         /// 
        /// 必须是八位字符串        /// 必须是八位字符串        ///         /// 
             public static string DesEncrypt(string str, string key, string iv)        {            if (string.IsNullOrEmpty(str))                return string.Empty;            HandlDesStr(ref key);            HandlDesStr(ref iv);            DESCryptoServiceProvider dsp = new DESCryptoServiceProvider();            using (MemoryStream memStream = new MemoryStream())            {                try                {                    CryptoStream crypStream = new CryptoStream(memStream, dsp.CreateEncryptor(Encoding.UTF8.GetBytes(key), Encoding.UTF8.GetBytes(iv)), CryptoStreamMode.Write);                    StreamWriter sWriter = new StreamWriter(crypStream);                    sWriter.Write(str);                    sWriter.Flush();                    crypStream.FlushFinalBlock();                    memStream.Flush();                    return Convert.ToBase64String(memStream.GetBuffer(), 0, (int)memStream.Length);                }                catch (Exception e)                {                    Debug.LogError(e);                    return string.Empty;                }            }        }        public static string DesDecrypt(string str, string key, string iv)        {            if (string.IsNullOrEmpty(str))                return string.Empty;            HandlDesStr(ref key);            HandlDesStr(ref iv);            DESCryptoServiceProvider dsp = new DESCryptoServiceProvider();            byte[] buffer = Convert.FromBase64String(str);            using (MemoryStream memStream = new MemoryStream())            {                try                {                    CryptoStream crypStream = new CryptoStream(memStream, dsp.CreateDecryptor(Encoding.UTF8.GetBytes(key), Encoding.UTF8.GetBytes(iv)), CryptoStreamMode.Write);                    crypStream.Write(buffer, 0, buffer.Length);                    crypStream.FlushFinalBlock();                    return ASCIIEncoding.UTF8.GetString(memStream.ToArray());                }                catch (Exception e)                {                    Debug.LogError(e);                    return string.Empty;                }            }        }        #endregion        #region Res        public static string RsaDecrypt(string str, string decryptKey)        {            if (string.IsNullOrEmpty(str))                return string.Empty;            byte[] dataToDecrypt = Convert.FromBase64String(str);            RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();            RSA.FromXmlString(decryptKey);            byte[] resultBytes = RSA.Decrypt(dataToDecrypt, false);            UnicodeEncoding ByteConverter = new UnicodeEncoding();            return ByteConverter.GetString(resultBytes);        }        public static KeyValuePair
     
       GetResaKeyPair()        {            RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();            string publicKey = RSA.ToXmlString(false);            string privateKey = RSA.ToXmlString(true);            return new KeyValuePair
      
       (publicKey, privateKey);        }        public static string ResEncrypt(string str, string encryptKey)        {            if (string.IsNullOrEmpty(str))                return string.Empty;            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();            rsa.FromXmlString(encryptKey);            UnicodeEncoding ByteConverter = new UnicodeEncoding();            byte[] DataToEncrypt = ByteConverter.GetBytes(str);            byte[] resultBytes = rsa.Encrypt(DataToEncrypt, false);            return Convert.ToBase64String(resultBytes);        }        #endregion    }