DES(Data Encryption Standard)数据加密标准

DES算法入口参数

DES算法的入口参数有三个:Key、Data、Mode。其中Key为7个字节共56位，是DES算法的工作密钥。Data为8个字节64位，是要被加密或解密的数据;Mode为DES的工作方法,有两种:加密或解密。

1. 加密解密文件

            /// <summary>
            /// Enctypt File
            /// </summary>
            /// <param name="sInputFilename"></param>
            /// <param name="sOutputFilename"></param>
            /// <param name="sKey"></param>
            public void EncryptFile(string sInputFilename, string sOutputFilename, string sKey)
            {
                DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
                //A 64 bit key and IV is required for this provider.
                //Set secret key For DES algorithm.
                DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
                //Set initialization vector.
                DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   
                FileStream fin = null;
                FileStream fout = null;
                CryptoStream cryptoStream = null;
                try
                {
                    fin = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
                    fout = new FileStream(sOutputFilename, FileMode.OpenOrCreate, FileAccess.Write);
                    cryptoStream = new CryptoStream(fout, DES.CreateEncryptor(), CryptoStreamMode.Write);
   
                    byte[] bin = new byte[];  //This is intermediate storage for the decryption.
                    long rdlen = ;              //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.
   
                    //Read from the input file, then encrypt and write to the output file.
                    while (rdlen < totlen)
                    {
                        len = fin.Read(bin, , );
                        cryptoStream.Write(bin, , len);
                        rdlen = rdlen + len;
                    }
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    if (cryptoStream != null) { cryptoStream.Close(); }
                    if (fout != null) { fout.Close(); }
                    if (fin != null) { fin.Close(); }
                }
            }
   
            /// <summary>
            /// Decrypt File
            /// </summary>
            /// <param name="sInputFilename"></param>
            /// <param name="sOutputFilename"></param>
            /// <param name="sKey"></param>
            public void DecryptFile(string sInputFilename, string sOutputFilename,string sKey)
            {
                DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
                //A 64 bit key and IV is required for this provider.
                //Set secret key For DES algorithm.
                DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
                //Set initialization vector.
                DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   
                FileStream fin = null;
                FileStream fout = null;
                CryptoStream cryptoStream = null;
                try
                {
                    fin = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
                    fout = new FileStream(sOutputFilename, FileMode.OpenOrCreate, FileAccess.Write);
                    cryptoStream = new CryptoStream(fin, DES.CreateDecryptor(), CryptoStreamMode.Read);
   
                    byte[] bin = new byte[];  //This is intermediate storage for the decryption.
                    long rdlen = ;              //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.
   
                    //Read from the input file, then encrypt and write to the output file.
                    while (rdlen < totlen)
                    {
                        len = cryptoStream.Read(bin, , );
                        if (len == ) { break; }
                        fout.Write(bin, , len);
                        rdlen = rdlen + len;
                    }
                }
                catch(Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    if (cryptoStream != null) { cryptoStream.Close(); }
                    if (fout != null) { fout.Close(); }
                    if (fin != null) { fin.Close(); }
                }
            }

2. 加密解密文本

            /// <summary>
            /// Encrypt Text
            /// </summary>
            public string DesEncrypt(string pToEncrypt, string sKey)
            {
                MemoryStream ms = null;
                CryptoStream ctyptoStream = null;
                try
                {
                    DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                    des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
                    des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   
                    byte[] inputByteArray = Encoding.ASCII.GetBytes(pToEncrypt);
   
                    ms = new System.IO.MemoryStream();
                    ctyptoStream = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
                    ctyptoStream.Write(inputByteArray, , inputByteArray.Length);
                    ctyptoStream.FlushFinalBlock();
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    if (ctyptoStream != null) { ctyptoStream.Close(); }
                    if (ms != null) { ms.Close(); }
                }
                return Convert.ToBase64String(ms.ToArray());
            }
   
            /// <summary>
            /// Dectypt Text
            /// </summary>
            public string DesDecrypt(string pToDecrypt, string sKey)
            {
                MemoryStream ms = null;
                CryptoStream ctyptoStream = null;
                try
                {
                    DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                    des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
                    des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   
                    byte[] inputByteArray = Convert.FromBase64String(pToDecrypt);
   
                    ms = new System.IO.MemoryStream();
                    ctyptoStream = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
                    ctyptoStream.Write(inputByteArray, , inputByteArray.Length);
                    ctyptoStream.FlushFinalBlock();
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    if (ctyptoStream != null) { ctyptoStream.Close(); }
                    if (ms != null) { ms.Close(); }
                }
                return Encoding.ASCII.GetString(ms.ToArray());
            }