代码笔记 | 用C#实现跟CI里面的加密解密

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 using System;using System.Text;using System.IO;using System.Security.Cryptography;  namespace CI{    class CI_Encrypt    {        private string key;        private string hash_type = "sha1";          public CI_Encrypt(string key = "")        {            if(key.Length > 0)            {                this.key = key;            }        }        public string encode(string data)        {            RijndaelManaged aes = new RijndaelManaged();            aes.KeySize = 256;            aes.BlockSize = 256;            aes.Padding = PaddingMode.Zeros;            aes.Mode = CipherMode.CBC;              aes.Key = this.get_key(key);            aes.GenerateIV();            var _IV = aes.IV;              byte[] buffer;                          ICryptoTransform AESEncrypt = aes.CreateEncryptor(aes.Key, aes.IV);            using (MemoryStream msEncrypt = new MemoryStream())            {                using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, AESEncrypt, CryptoStreamMode.Write))                {                    using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))                    {                          //Write all data to the stream.                        swEncrypt.Write(data);                    }                    buffer = msEncrypt.ToArray();                }            }              var enc = new byte [ _IV.Length + buffer.Length ];              Array.Copy(_IV,enc ,_IV.Length);            Array.Copy(buffer,0,enc,_IV.Length,buffer.Length);              return this.add_cipher_noise(enc);        }          public string decode(string data)        {            string plainText;            byte[] _enc_data = this.remove_cipher_noise(Convert.FromBase64String(data));            using (RijndaelManaged aes = new RijndaelManaged())            {                aes.KeySize = 256;                aes.BlockSize = 256;                aes.Padding = PaddingMode.Zeros;                aes.Mode = CipherMode.CBC;                aes.Key = this.get_key(key);                var _IV = new byte[aes.IV.Length];                Array.Copy(_enc_data, _IV, _IV.Length);                aes.IV = _IV;                var endata = new byte[_enc_data.Length - aes.IV.Length];                Array.Copy(_enc_data, aes.IV.Length, endata, 0, endata.Length);                  // Create a decrytor to perform the stream transform.                ICryptoTransform decryptor = aes.CreateDecryptor(aes.Key, aes.IV);                  // Create the streams used for decryption.                 using (MemoryStream msDecrypt = new MemoryStream(endata))                {                    using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))                    {                        using (StreamReader srDecrypt = new StreamReader(csDecrypt))                        {                              // Read the decrypted bytes from the decrypting stream                             // and place them in a string.                            plainText = srDecrypt.ReadToEnd();                        }                    }                }              }            return plainText;        }          public string add_cipher_noise(byte[] data)        {            string hashkey = this.hash(System.Text.Encoding.Default.GetString(this.get_key(this.key)));            char[] keyChar = hashkey.ToCharArray();            byte[] encrpytData = new byte[data.Length];            for (int i = 0, j = 0; i < data.Length; i++, j++)            {                if (j >= hashkey.Length)                {                    j = 0;                }                var temp = (((int)data[i] + (int)keyChar[j]) % 256);                encrpytData[i] = (byte)temp;            }            return System.Convert.ToBase64String(encrpytData);        }          public byte[] remove_cipher_noise(byte[] data)        {            string hashkey = this.hash(System.Text.Encoding.Default.GetString(this.get_key(this.key)));            char[] keyChar = hashkey.ToCharArray();            byte[] encrpytData = new byte[data.Length];            int temp;              for (int i = 0, j = 0; i < data.Length; i++, j++)            {                if (j >= hashkey.Length)                {                    j = 0;                }                temp = (int)data[i] - (int)keyChar[j];                if(temp < 0)                {                    temp += 256;                }                encrpytData[i] = (byte)temp;            }            return encrpytData;        }          private string hash(string key)        {            byte[] hashBytes;            if (this.hash_type == "sha1")            {                SHA1 sha = new SHA1CryptoServiceProvider();                hashBytes = (sha.ComputeHash(System.Text.Encoding.Default.GetBytes(key)));            }            else            {                MD5 md5 = new MD5CryptoServiceProvider();                hashBytes = (md5.ComputeHash(System.Text.Encoding.Default.GetBytes(key)));            }            StringBuilder sb = new StringBuilder();            for (int i = 0; i < hashBytes.Length; i++)            {                sb.Append(hashBytes[i].ToString("X2"));            }            return sb.ToString().ToLower();        }          private byte[] get_key(string key)        {            MD5 md5 = new MD5CryptoServiceProvider();            byte[] hashBytes = (md5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(key)));            StringBuilder sb = new StringBuilder();            for (int i = 0; i < hashBytes.Length; i++)            {                sb.Append(hashBytes[i].ToString("X2"));            }            return System.Text.Encoding.Default.GetBytes(sb.ToString().ToLower());        }    }}
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