Ejemplo n.º 1
0
        /// <summary>
        /// Task 3. Collision
        /// </summary>
        private static void FindAndPrintCollision()
        {
            // asking user how many bits (counting from the beginning of initial message) he wants to be the same
            var k = ConsoleMessager.AskHashLength();

            // asking length for future string value generating
            var L = ConsoleMessager.AskStringLength();

            // a dictionary where key is a bits piece and value is a random generated string
            var kBitsStringHashDict = new Dictionary <string, string>();

            while (true)
            {
                var randString     = GetRandomString(L);
                var mdFourInstance = GetHashFromString(randString);
                var firstBitsList  = GetBitsList(mdFourInstance.ResultHashBytes, k);

                var firstBitsString = Helper.PrintList(firstBitsList);

                // when we try to add the same key an exception is going to be raised.
                // that means a collision has been found.
                try
                {
                    kBitsStringHashDict.Add(firstBitsString, randString);
                }
                catch (ArgumentException e)
                {
                    var firstHash  = GetHashFromString(kBitsStringHashDict[firstBitsString]).ResultHashString;
                    var secondHash = mdFourInstance.ResultHashString;

                    var firstRandomString  = kBitsStringHashDict[firstBitsString];
                    var secondRandomString = randString;
                    var N = kBitsStringHashDict.Count;

                    ConsoleMessager.PrintCollisionResults(firstHash, firstRandomString, secondHash, secondRandomString,
                                                          firstBitsString, N);
                    break;
                }
            }
        }
Ejemplo n.º 2
0
        /// <summary>
        /// Task 4. Prototype
        /// </summary>
        private static void FindAndPrintPrototype()
        {
            Console.WriteLine("Enter a password:"******"";

            int N = 0;

            while (prototypeString == "")
            {
                N++;
                var randomString = GetRandomString(L);
                var mdFourRandomStringInstance = GetHashFromString(randomString);
                var randomHashFirstBitsList    = GetBitsList(mdFourRandomStringInstance.ResultHashBytes, k);
                var randomHashFirstBitsString  = Helper.PrintList(randomHashFirstBitsList);

                if (randomHashFirstBitsString == firstBitsString)
                {
                    Console.WriteLine(String.Format("We found a string with the same {0} first bits in hash for your password '{1}'", k, inputPassword));
                    prototypeString = randomString;
                    ConsoleMessager.PrintCollisionResults(mdFourInitialInstance.ResultHashString, inputPassword,
                                                          mdFourRandomStringInstance.ResultHashString, randomString, randomHashFirstBitsString, N);
                }
            }
        }