. NET encryption and decryption of binary files (C #)

Binary | encryption | decryption

The following class implements the file encryption and decryption operations, the test of several file types are no problem, and now share with you.

Namespace Mycryptohelp
{
<summary>
Exception Handling Class
</summary>
public class Cryptohelpexception:applicationexception
{
Public cryptohelpexception (String msg): Base (msg) {}
}

<summary>
Crypthelp
</summary>
public class Cryptohelp
{
Private Const ULONG Fc_tag = 0XFC010203040506CF;

  private const int buffer_size = 128*1024;
  
  ///<summary>
  ///Verify that two byte arrays are the same
  ///</ Summary>
  ///<param name= "B1" >byte array </param>
  ///<param name= "B2" >byte array </param>
  ///<returns>true-equal </returns>
  private Static BOOL Checkbytearrays (byte[] B1, byte[] b2)
  {
   if (B1. Length = = B2. Length)
   {
    for (int i = 0; I < B1. Length; ++i)
    {
     if (B1[i]!= b2[i])
       return false;
    }
    return true;
   }
   return false;
  }

  ///<summary>
  ///Create Rijndael symmetricalgorithm
  ///</ Summary>
  ///<param name= "password" > password </param>
  ///<param name= " Salt "></param>
  ///<returns> Cryptographic object </returns>
  private Static SymmetricAlgorithm Createrijndael (string password, byte[] salt)
  {
    PasswordDeriveBytes pdb = new PasswordDeriveBytes (Password,salt, "SHA256", 1000);
   
   symmetricalgorithm SMA = Rijndael.create ();
   sma. KeySize = 256;
   sma. Key = pdb. GetBytes (32);
   sma. Padding = PADDINGMODE.PKCS7;
   return SMA;
  }

<summary>
Random number generation of encrypted files
</summary>
private static RandomNumberGenerator Rand = new RNGCryptoServiceProvider ();

<summary>
Generate a random byte array of the specified length
</summary>
<param name= "Count" >byte array length </param>
<returns> Random byte array </returns>
private static byte[] generaterandombytes (int count)
{
byte[] bytes = new Byte[count];
Rand. GetBytes (bytes);
return bytes;
}

<summary>
Encrypting files
</summary>
<param name= "InFile" > Encrypted file </param>
<param name= "outfile" > Encrypted input file </param>
<param name= "password" > Encrypted password </param>
public static void EncryptFile (String inFile, string outfile, string password)
{
using (FileStream fin = File.openread (inFile),
Fout = File.openwrite (outfile))
{
Long lsize = Fin. Length; Input file length
int size = (int) lsize;
byte[] bytes = new Byte[buffer_size]; Cache
int read =-1; Input file Read quantity
int value = 0;

Get IV and salt
byte[] IV = generaterandombytes (16);
byte[] Salt = generaterandombytes (16);

Creating an Encrypted object
SymmetricAlgorithm SMA = cryptohelp.createrijndael (password, salt);
SMA.IV = IV;

Writes IV and salt at the beginning of the output file
Fout. Write (Iv,0,iv. Length);
Fout. Write (Salt,0,salt. Length);

Create Hash encryption
HashAlgorithm hasher = SHA256. Create ();
using (CryptoStream cout = new CryptoStream (Fout,sma. CreateEncryptor (), CryptoStreamMode.Write),
Chash = new CryptoStream (stream.null,hasher,cryptostreammode.write))
{
BinaryWriter bw = new BinaryWriter (cout);
Bw. Write (lsize);

Bw. Write (Fc_tag);

Read-write byte block to encrypted stream buffer
while (read = Fin. Read (bytes,0,bytes. Length))!= 0)
{
cout. Write (Bytes,0,read);
Chash. Write (Bytes,0,read);
Value + = read;
}
Turn off the encrypted stream
Chash. Flush ();
Chash. Close ();

Read Hash
Byte[] hash = hasher. Hash;

Input file Write hash
cout. Write (Hash,0,hash. Length);

Close file stream
cout. Flush ();
cout. Close ();
}
}
}

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