Exemplo n.º 1
0
        private byte[] InverseSecondRound(byte[] cipherText, byte[] roundKey)
        {
            var inversedRoundKey           = Aes16Helper.AddRoundKey(cipherText, roundKey);
            var inversedShiftRow           = Aes16Helper.ShiftRow(inversedRoundKey);
            var inversedNibbleSubstitution = Aes16Helper.InverseNibbleSubstitution(inversedShiftRow);

            return(inversedNibbleSubstitution);
        }
        private byte[] GetThirdSubKey(byte[] key)
        {
            var secondSubKey = GetSecondSubKey(key);
            var firstByte    = (byte)(secondSubKey[0] ^ 0b00110000 ^ Aes16Helper.SubNib(Aes16Helper.RotNib(secondSubKey[1])));
            var secondByte   = (byte)(firstByte ^ secondSubKey[1]);

            return(new[] { firstByte, secondByte });
        }
Exemplo n.º 3
0
        private byte[] InverseFirstRound(byte[] firstRoundCipherText, byte[] roundKey)
        {
            var inversedRoundKey           = Aes16Helper.AddRoundKey(firstRoundCipherText, roundKey);
            var inversedMixColumns         = Aes16Helper.InverseMixColumns(inversedRoundKey);
            var inversedShiftRow           = Aes16Helper.ShiftRow(inversedMixColumns);
            var inversedNibbleSubstitution = Aes16Helper.InverseNibbleSubstitution(inversedShiftRow);

            return(inversedNibbleSubstitution);
        }
Exemplo n.º 4
0
        private byte[] GetSecondRoundResult(byte[] firstRoundResult, byte[] subKey)
        {
            var nibbled = Aes16Helper.NibbleSubstitution(firstRoundResult);
            var secondFourBitsOfFirstByte  = (byte)(nibbled[0] & 0b00001111);
            var secondFourBitsOfSecondByte = (byte)(nibbled[1] & 0b00001111);
            var newFirstByte  = (byte)((nibbled[0] & 0b11110000) | secondFourBitsOfSecondByte);
            var newSecondByte = (byte)((nibbled[1] & 0b11110000) | secondFourBitsOfFirstByte);
            var shiftedBytes  = new[] { newFirstByte, newSecondByte };

            return(Aes16Helper.AddRoundKey(shiftedBytes, subKey));
        }
Exemplo n.º 5
0
        private byte[] GetFirstRoundResult(byte[] zeroRoundResult, byte[] roundKey)
        {
            // Nibble substitution
            var nibbled = Aes16Helper.NibbleSubstitution(zeroRoundResult);

            // Shift row
            var shiftedRowBytes = Aes16Helper.ShiftRow(nibbled);
            var mixedBytes      = Aes16Helper.MixColumns(shiftedRowBytes);

            return(Aes16Helper.AddRoundKey(new[] { mixedBytes[0], mixedBytes[1] }, roundKey));
        }
        private byte[] GetSecondSubKey(byte[] key)
        {
            var firstSubKey = GetFirstSubKey(key);
            var a           = (byte)(firstSubKey[0] ^ 0b10000000);
            var c           = Aes16Helper.RotNib(firstSubKey[1]);
            var b           = Aes16Helper.SubNib(c);
            var firstByte   = (byte)(a ^ b);
            var secondByte  = (byte)(firstByte ^ firstSubKey[1]);

            return(new[] { firstByte, secondByte });
        }
Exemplo n.º 7
0
        private byte[] InverseZeroRound(byte[] zeroRoundCipherText, byte[] roundKey)
        {
            var inversedRoundKey = Aes16Helper.AddRoundKey(zeroRoundCipherText, roundKey);

            return(inversedRoundKey);
        }
Exemplo n.º 8
0
 private byte[] GetZeroRoundResult(byte[] plainText, byte[] roundKey)
 {
     return(Aes16Helper.AddRoundKey(plainText, roundKey));
 }