processdes.cs

g729 coding ipaddressing

            for (int i = 0; i < 8; i++)
            {
                if (binary >= factor)
                {
                    binary -= factor;
                    binarystring += "1";
                }
                else
                {
                    binarystring += "0";
                }
                factor /= 2;
            }

            return binarystring;
        }

        public static byte FromBinaryToByte(string binary)
        {
            byte value = 0;
            int factor = 128;

            for (int i = 0; i < 8; i++)
            {
                if (binary[i] == '1')
                {
                    value += (byte)factor;                    
                }

                factor /= 2;
            }

            return value;
        }
        #endregion

        #region Transform a hex integer to a binary number
        public string FromHexToBinary(string hexstring)
        {
            string binarystring = "";

            try
            {
                for (int i = 0; i < hexstring.Length; i++)
                {
                    int hex = Convert.ToInt32(hexstring[i].ToString(), 16);

                    int factor = 8;

                    for(int j=0; j<4; j++)
                    {
                        if (hex >= factor)
                        {
                            hex -= factor;
                            binarystring += "1";
                        }
                        else
                        {
                            binarystring += "0";
                        }
                        factor /= 2;
                    }
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message + " - wrong hexa integer format.");
            }

            return binarystring;
        }
        #endregion

        #region Permutation
        public string DoPermutation(string text, int[] order)
        {
            StringBuilder PermutatedText = new StringBuilder(order.Length);

            for (int i = 0; i < order.Length; i++)
            {
                PermutatedText.Append(text[order[i] - 1]);
            }

            return PermutatedText.ToString();
        }
        
        //For SBoxes Transformation
        public string DoPermutation(string text, int[,] order)
        {
            string PermutatedText = "";

            int rowIndex = Convert.ToInt32(text[0].ToString() + text[text.Length - 1].ToString(), 2);
            int colIndex = Convert.ToInt32(text.Substring(1, 4), 2);

            PermutatedText = ProcessDES.FromDeciamlToBinary(order[rowIndex, colIndex]);

            return PermutatedText;
        }        
        #endregion

        #region Divide a text to left and right halves
        public string SetLeftHalvesKey(string text)
        {
            return this.SetHalvesKey(true, text);
        }

        public string SetRightHalvesKey(string text)
        {
            return this.SetHalvesKey(false, text);       
        }

        public string SetHalvesKey(bool IsLeft, string text)
        {
            if ((text.Length % 8) != 0)
            {
                Console.WriteLine("The key is not multiple of 8bit.");
                return null;
            }

            int midindex = (text.Length / 2) - 1;

            string result = "";

            if (IsLeft)
            {
                result = text.Substring(0, midindex + 1);
            }
            else
            {
                result = text.Substring(midindex + 1);
            }

            return result;
        }
        #endregion

        #region Do Leftshift
        public string LeftShift(string text)
        {
            return this.LeftShift(text, 1);
        }

        public string LeftShift(string text, int count)
        {
            if (count < 1)
            {
                Console.WriteLine("The count of leftshift is must more than 1 time.");
                return null;
            }

            string temp = text.Substring(0, count);
            StringBuilder shifted = new StringBuilder(text.Length);
            shifted.Append(text.Substring(count) + temp);

            return shifted.ToString();
        }
        #endregion

        #region Key甸阑 备窍绰 皋辑靛 - Get all of keys
        public Keys SetAllKeys(string C0, string D0)
        {
            Keys keys = new Keys();
            keys.Cn[0] = C0;
            keys.Dn[0] = D0;

            for (int i = 1; i < keys.Cn.Length; i++)
            {
                keys.Cn[i] = this.LeftShift(keys.Cn[i - 1], DESData.nrOfShifts[i]);
                keys.Dn[i] = this.LeftShift(keys.Dn[i - 1], DESData.nrOfShifts[i]);
                keys.Kn[i - 1] = this.DoPermutation(keys.Cn[i] + keys.Dn[i], DESData.pc_2);
            }          

            return keys;
        }
        #endregion

        #region Do Encryption
        public string FinalEncription(string L0, string R0, Keys keys, bool IsReverse)
        {
            string Ln = "", Rn = "", Ln_1 = L0, Rn_1 = R0;

            int i = 0;

            if (IsReverse == true)
            {
                i = 15;
            }

            while (this.IsEnough(i, IsReverse))
            {
                Ln = Rn_1;
                Rn = this.XOR(Ln_1, this.f(Rn_1, keys.Kn[i]));

                //Next Step of L1, R1 is L2 = R1, R2 = L1 + f(R1, K2), hence, value of Step1's Ln, Rn is Rn_1, Ln_1 in Step2.
                Ln_1 = Ln;
                Rn_1 = Rn;

                if (IsReverse == false)
                {
                    i += 1;
                }
                else
                {
                    i -= 1;
                }
            }

            string R16L16 = Rn + Ln;

            string Encripted_Text = this.DoPermutation(R16L16, DESData.ip_1);

            return Encripted_Text;
        }

        public /*static*/ bool IsEnough(int i, bool IsReverse)
        {
            return (IsReverse == false) ? i < 16 : i >= 0;            
        }
        #endregion

        #region The function f
        public string f(string Rn_1, string Kn)
        {
            string E_Rn_1 = this.E_Selection(Rn_1);

            string XOR_Rn_1_Kn = this.XOR(E_Rn_1, Kn);

            string sBoxedText = this.sBox_Transform(XOR_Rn_1_Kn);

            string P_sBoxedText = this.P(sBoxedText);

            return P_sBoxedText;
        }
        #endregion

        #region The function P
        public string P(string text)
        {
            string PermutatedText = "";

            PermutatedText = this.DoPermutation(text, DESData.pc_p);

            return PermutatedText;
        }
        #endregion

        #region SBoxes transformation
        public string sBox_Transform(string text)
        {
            StringBuilder TransformedText = new StringBuilder(32);

            for (int i = 0; i < 8; i++)
            {
                string temp = text.Substring(i * 6, 6);
                TransformedText.Append(this.DoPermutation(temp, DESData.sBoxes[i]));
            }

            return TransformedText.ToString();
        }
        #endregion
         
        #region E Selection
        public string E_Selection(string Rn_1)
        {
            string ExpandedText = this.DoPermutation(Rn_1, DESData.pc_e);

            return ExpandedText;
        }
        #endregion

        #region XOR operation
        public string XOR(string text1, string text2)
        {
            if (text1.Length != text2.Length)
            {
                Console.WriteLine("Two data blocks for XOR are must get same size.");
                return null;
            }

            StringBuilder XORed_Text = new StringBuilder(text1.Length);

            for (int i = 0; i < text1.Length; i++)
            {
                if (text1[i] != text2[i])
                {
                    XORed_Text.Append("1");
                }
                else
                {
                    XORed_Text.Append("0");
                }
            }

            return XORed_Text.ToString();
        }
        #endregion
    }
}