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- using System;
- using System.Collections.Generic;
- using System.Linq;
- using System.Text;
- using System.Threading.Tasks;
- using System.Security;
- using System.Security.Cryptography;
- using System.IO;
- using System.Security.Permissions;
- using System.Runtime.InteropServices;
- namespace SafeConverter
- {
- class Cryption
- {
- // Call this function to remove the key from memory after use for security
- [System.Runtime.InteropServices.DllImport("KERNEL32.DLL", EntryPoint = "RtlZeroMemory")]
- public static extern bool ZeroMemory(IntPtr Destination, int Length);
- // Function to Generate a 64 bits Key.
- static string GenerateKey()
- {
- // Create an instance of Symetric Algorithm. Key and IV is generated automatically.
- DESCryptoServiceProvider desCrypto = (DESCryptoServiceProvider)DESCryptoServiceProvider.Create();
- // Use the Automatically generated key for Encryption.
- return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
- }
- static void EncryptFile(string sInputFilename,
- string sOutputFilename,
- string sKey)
- {
- FileStream fsInput = new FileStream(sInputFilename,
- FileMode.Open,
- FileAccess.Read);
- FileStream fsEncrypted = new FileStream(sOutputFilename,
- FileMode.Create,
- FileAccess.Write);
- DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
- DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
- DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
- ICryptoTransform desencrypt = DES.CreateEncryptor();
- CryptoStream cryptostream = new CryptoStream(fsEncrypted,
- desencrypt,
- CryptoStreamMode.Write);
- byte[] bytearrayinput = new byte[fsInput.Length];
- fsInput.Read(bytearrayinput, 0, bytearrayinput.Length);
- cryptostream.Write(bytearrayinput, 0, bytearrayinput.Length);
- cryptostream.Close();
- fsInput.Close();
- fsEncrypted.Close();
- }
- static 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);
- //Create a file stream to read the encrypted file back.
- FileStream fsread = new FileStream(sInputFilename,
- FileMode.Open,
- FileAccess.Read);
- //Create a DES decryptor from the DES instance.
- ICryptoTransform desdecrypt = DES.CreateDecryptor();
- //Create crypto stream set to read and do a
- //DES decryption transform on incoming bytes.
- CryptoStream cryptostreamDecr = new CryptoStream(fsread,
- desdecrypt,
- CryptoStreamMode.Read);
- //Print the contents of the decrypted file.
- StreamWriter fsDecrypted = new StreamWriter(sOutputFilename);
- fsDecrypted.Write(new StreamReader(cryptostreamDecr).ReadToEnd());
- fsDecrypted.Flush();
- fsDecrypted.Close();
- }
- public static void encrypt(String filename)
- {
- // Must be 64 bits, 8 bytes.
- // Distribute this key to the user who will decrypt this file.
- string sSecretKey;
- // Get the Key for the file to Encrypt.
- sSecretKey = GenerateKey();
- // For additional security Pin the key.
- GCHandle gch = GCHandle.Alloc(sSecretKey, GCHandleType.Pinned);
- String[] array = filename.Split('.');
- String newfile = array[0];
- EncryptFile(@filename,@newfile + "EN.txt",sSecretKey);
- // Remove the Key from memory.
- ZeroMemory(gch.AddrOfPinnedObject(), sSecretKey.Length * 2);
- gch.Free();
- }
- public static void decrypt(String filename)
- {
- // Must be 64 bits, 8 bytes.
- // Distribute this key to the user who will decrypt this file.
- string sSecretKey;
- // Get the Key for the file to Encrypt.
- sSecretKey = GenerateKey();
- // For additional security Pin the key.
- GCHandle gch = GCHandle.Alloc(sSecretKey, GCHandleType.Pinned);
- String[] array = filename.Split('.');
- String newfile = array[0];
- DecryptFile(@filename, @newfile + "DE.txt", sSecretKey);
- // Remove the Key from memory.
- ZeroMemory(gch.AddrOfPinnedObject(), sSecretKey.Length * 2);
- gch.Free();
- }
- private static String getRandomFileAss()
- {
- int maxSize = 5;
- char[] chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890".ToCharArray();
- byte[] data = new byte[1];
- RNGCryptoServiceProvider crypto = new RNGCryptoServiceProvider();
- crypto.GetNonZeroBytes(data);
- data = new byte[maxSize];
- crypto.GetNonZeroBytes(data);
- StringBuilder result = new StringBuilder(maxSize);
- foreach (byte b in data)
- {
- result.Append(chars[b % (chars.Length - 1)]);
- }
- return result.ToString();
- }
- }
- }
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