HMACRIPEMD160.HMACRIPEMD160() Constructor

public HMACRIPEMD160 ()

public HMACRIPEMD160 ()

public function HMACRIPEMD160 ()

Not applicable.

using System;
using System.IO;
using System.Security.Cryptography;

public class HMACRIPEMD160example
{
	// Computes a keyed hash for a source file, creates a target file with the keyed hash
	// prepended to the contents of the source file, then decrypts the file and compares
	// the source and the decrypted files.
	public static void EncodeFile(byte[] key, String sourceFile, String destFile)
	{
		// Initialize the keyed hash object.
		HMACRIPEMD160 myhmacRIPEMD160 = new HMACRIPEMD160(key);
		FileStream inStream = new FileStream(sourceFile, FileMode.Open);
		FileStream outStream = new FileStream(destFile, FileMode.Create);
		// Compute the hash of the input file.
		byte[] hashValue = myhmacRIPEMD160.ComputeHash(inStream);
		// Reset inStream to the beginning of the file.
		inStream.Position = 0;
		// Write the computed hash value to the output file.
		outStream.Write(hashValue, 0, hashValue.Length);
		// Copy the contents of the sourceFile to the destFile.
		int bytesRead;
		// read 1K at a time
		byte[] buffer = new byte[1024]; 
		do
		{
			// Read from the wrapping CryptoStream.
			bytesRead = inStream.Read(buffer,0,1024); 
			outStream.Write(buffer, 0, bytesRead);
		} while (bytesRead > 0); 
		myhmacRIPEMD160.Clear();
		// Close the streams
		inStream.Close();
		outStream.Close();
		return;
	} // end EncodeFile


	// Decrypt the encoded file and compare to original file.
	public static bool DecodeFile(byte[] key, String sourceFile)
	{
		// Initialize the keyed hash object. 
		HMACRIPEMD160 hmacRIPEMD160 = new HMACRIPEMD160(key);
		// Create an array to hold the keyed hash value read from the file.
		byte[] storedHash = new byte[hmacRIPEMD160.HashSize/8];
		// Create a FileStream for the source file.
		FileStream inStream = new FileStream(sourceFile, FileMode.Open);
		// Read in the storedHash.
		inStream.Read(storedHash, 0, storedHash.Length);
		// Compute the hash of the remaining contents of the file.
		// The stream is properly positioned at the beginning of the content, 
		// immediately after the stored hash value.
		byte[] computedHash = hmacRIPEMD160.ComputeHash(inStream);
		// compare the computed hash with the stored value
		for (int i =0; i < storedHash.Length; i++)
		{
			if (computedHash[i] != storedHash[i])
			{
				Console.WriteLine("Hash values differ! Encoded file has been tampered with!");
				return false;
			}
		}
		Console.WriteLine("Hash values agree -- no tampering occurred.");
		return true;
	} //end DecodeFile

	private const string usageText = "Usage: HMACRIPEMD160 inputfile.txt encryptedfile.hsh\nYou must specify the two file names. Only the first file must exist.\n";
	public static void Main(string[] Fileargs)
	{
		//If no file names are specified, write usage text.
		if (Fileargs.Length < 2)
		{
			Console.WriteLine(usageText);
		}
		else
		{
			try
			{
				// Create a random key using a random number generator. This would be the
				//  secret key shared by sender and receiver.
				byte[] secretkey = new Byte[64];
				//RNGCryptoServiceProvider is an implementation of a random number generator.
				RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
				// The array is now filled with cryptographically strong random bytes.
				rng.GetBytes(secretkey); 

				// Use the secret key to encode the message file.
				EncodeFile(secretkey, Fileargs[0], Fileargs[1]);

				// Take the encoded file and decode
				DecodeFile(secretkey, Fileargs[1]);
			}
			catch (IOException e)
			{
				Console.WriteLine("Error: File not found",e);
			}
		} //end if-else

	}  //end main
} //end class

import System.*;
import System.IO.*;
import System.Security.Cryptography.*;

public class HMACRIPEMD160Example
{
    // Computes a keyed hash for a source file, creates a target file with the
    //  keyed hash prepended to the contents of the source file, then decrypts
    //  the file and compares the source and the decrypted files.
    public static void EncodeFile(ubyte key[], String sourceFile, 
        String destFile)
    {
        // Initialize the keyed hash object.
        HMACRIPEMD160 myhmacRIPEMD160 = new HMACRIPEMD160(key);
        FileStream inStream = new FileStream(sourceFile, FileMode.Open);
        FileStream outStream = new FileStream(destFile, FileMode.Create);

        // Compute the hash of the input file.
        ubyte hashValue[] = myhmacRIPEMD160.ComputeHash(inStream);

        // Reset inStream to the beginning of the file.
        inStream.set_Position(0);

        // Write the computed hash value to the output file.
        outStream.Write(hashValue, 0, hashValue.length);

        // Copy the contents of the sourceFile to the destFile.
        int bytesRead;

        // read 1K at a time
        ubyte buffer[] = new ubyte[1024];
        do {
            // Read from the wrapping CryptoStream.
            bytesRead = inStream.Read(buffer, 0, 1024);
            outStream.Write(buffer, 0, bytesRead);
        } while (bytesRead > 0);
        myhmacRIPEMD160.Clear();

        // Close the streams
        inStream.Close();
        outStream.Close();
        return;
    } // end EncodeFile
    
    // Decrypt the encoded file and compare to original file.
    public static boolean DecodeFile(ubyte[] key, String sourceFile)
    {
        // Initialize the keyed hash object. 
        HMACRIPEMD160 hmacRIPEMD160 = new HMACRIPEMD160(key);

        // Create an array to hold the keyed hash value read from the file.
        ubyte storedHash[] = new ubyte[hmacRIPEMD160.get_HashSize() / 8];

        // Create a FileStream for the source file.
        FileStream inStream = new FileStream(sourceFile, FileMode.Open);

        // Read in the storedHash.
        inStream.Read(storedHash, 0, storedHash.length);

        // Compute the hash of the remaining contents of the file.
        // The stream is properly positioned at the beginning of the content, 
        // immediately after the stored hash value.
        ubyte computedHash[] = hmacRIPEMD160.ComputeHash(inStream);

        // compare the computed hash with the stored value
        for (int i = 0; i < storedHash.length; i++) {
            if (computedHash.get_Item(i) != storedHash.get_Item(i)) {
                Console.WriteLine("Hash values differ! Encoded file has been" 
                    + "tampered with!");
                return false;
            }
        }
        Console.WriteLine("Hash values agree -- no tampering occurred.");
        return true;
    } //end DecodeFile

    private static String usageText = "Usage: HMACRIPEMD160 inputfile.txt " 
        + "encryptedfile.hsh\nYou must specify the two file names. Only the " 
        + " first file must exist.\n";

    public static void main(String[] fileargs)
    {
        //If no file names are specified, write usage text.
        if (fileargs.length < 2) {
            Console.WriteLine(usageText);
        }
        else {
            try {
                // Create a random key using a random number generator. This 
                // would be the secret key shared by sender and receiver.
                ubyte secretKey[] = new ubyte[64];

                //RNGCryptoServiceProvider is an implementation of a random
                // number generator.
                RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();

                // The array is now filled with cryptographically strong
                // random bytes.
                rng.GetBytes(secretKey);

                // Use the secret key to encode the message file.
                EncodeFile(secretKey, fileargs[0], fileargs[1]);

                // Take the encoded file and decode
                DecodeFile(secretKey, fileargs[1]);
            }
            catch (IOException e) {
                Console.WriteLine("Error: File not found", e);
            }
        }//end if-else
    } //end main
} //end class HMACRIPEMD160Example