cryptography

hai frands am going to do a new encryption method who are intersted in cryptography they acan join with me (renjithsraj@live.com), i need ideas about encryption and decryption techniques

import java.util.*;

class DES {
// Initial Permutation table
private static final byte[] IP = {
58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6,
64, 56, 48, 40, 32, 24, 16, 8,
57, 49, 41, 33, 25, 17, 9, 1,
59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5,
63, 55, 47, 39, 31, 23, 15, 7
};

``````// Permuted Choice 1 table
private static final byte[] PC1 = {
57, 49, 41, 33, 25, 17, 9,
1,  58, 50, 42, 34, 26, 18,
10, 2,  59, 51, 43, 35, 27,
19, 11, 3,  60, 52, 44, 36,
63, 55, 47, 39, 31, 23, 15,
7,  62, 54, 46, 38, 30, 22,
14, 6,  61, 53, 45, 37, 29,
21, 13, 5,  28, 20, 12, 4
};

// Permuted Choice 2 table
private static final byte[] PC2 = {
14, 17, 11, 24, 1,  5,
3,  28, 15, 6,  21, 10,
23, 19, 12, 4,  26, 8,
16, 7,  27, 20, 13, 2,
41, 52, 31, 37, 47, 55,
30, 40, 51, 45, 33, 48,
44, 49, 39, 56, 34, 53,
46, 42, 50, 36, 29, 32
};

// Array to store the number of rotations that are to be done on each round
private static final byte[] rotations = {
1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
};

// Expansion (aka P-box) table
private static final byte[] E = {
32, 1,  2,  3,  4,  5,
4,  5,  6,  7,  8,  9,
8,  9,  10, 11, 12, 13,
12, 13, 14, 15, 16, 17,
16, 17, 18, 19, 20, 21,
20, 21, 22, 23, 24, 25,
24, 25, 26, 27, 28, 29,
28, 29, 30, 31, 32, 1
};

// S-boxes (i.e. Substitution boxes)
private static final byte[][] S = { {
14, 4,  13, 1,  2,  15, 11, 8,  3,  10, 6,  12, 5,  9,  0,  7,
0,  15, 7,  4,  14, 2,  13, 1,  10, 6,  12, 11, 9,  5,  3,  8,
4,  1,  14, 8,  13, 6,  2,  11, 15, 12, 9,  7,  3,  10, 5,  0,
15, 12, 8,  2,  4,  9,  1,  7,  5,  11, 3,  14, 10, 0,  6,  13
}, {
15, 1,  8,  14, 6,  11, 3,  4,  9,  7,  2,  13, 12, 0,  5,  10,
3,  13, 4,  7,  15, 2,  8,  14, 12, 0,  1,  10, 6,  9,  11, 5,
0,  14, 7,  11, 10, 4,  13, 1,  5,  8,  12, 6,  9,  3,  2,  15,
13, 8,  10, 1,  3,  15, 4,  2,  11, 6,  7,  12, 0,  5,  14, 9
}, {
10, 0,  9,  14, 6,  3,  15, 5,  1,  13, 12, 7,  11, 4,  2,  8,
13, 7,  0,  9,  3,  4,  6,  10, 2,  8,  5,  14, 12, 11, 15, 1,
13, 6,  4,  9,  8,  15, 3,  0,  11, 1,  2,  12, 5,  10, 14, 7,
1,  10, 13, 0,  6,  9,  8,  7,  4,  15, 14, 3,  11, 5,  2,  12
}, {
7,  13, 14, 3,  0,  6,  9,  10, 1,  2,  8,  5,  11, 12, 4,  15,
13, 8,  11, 5,  6,  15, 0,  3,  4,  7,  2,  12, 1,  10, 14, 9,
10, 6,  9,  0,  12, 11, 7,  13, 15, 1,  3,  14, 5,  2,  8,  4,
3,  15, 0,  6,  10, 1,  13, 8,  9,  4,  5,  11, 12, 7,  2,  14
}, {
2,  12, 4,  1,  7,  10, 11, 6,  8,  5,  3,  15, 13, 0,  14, 9,
14, 11, 2,  12, 4,  7,  13, 1,  5,  0,  15, 10, 3,  9,  8,  6,
4,  2,  1,  11, 10, 13, 7,  8,  15, 9,  12, 5,  6,  3,  0,  14,
11, 8,  12, 7,  1,  14, 2,  13, 6,  15, 0,  9,  10, 4,  5,  3
}, {
12, 1,  10, 15, 9,  2,  6,  8,  0,  13, 3,  4,  14, 7,  5,  11,
10, 15, 4,  2,  7,  12, 9,  5,  6,  1,  13, 14, 0,  11, 3,  8,
9,  14, 15, 5,  2,  8,  12, 3,  7,  0,  4,  10, 1,  13, 11, 6,
4,  3,  2,  12, 9,  5,  15, 10, 11, 14, 1,  7,  6,  0,  8,  13
}, {
4,  11, 2,  14, 15, 0,  8,  13, 3,  12, 9,  7,  5,  10, 6,  1,
13, 0,  11, 7,  4,  9,  1,  10, 14, 3,  5,  12, 2,  15, 8,  6,
1,  4,  11, 13, 12, 3,  7,  14, 10, 15, 6,  8,  0,  5,  9,  2,
6,  11, 13, 8,  1,  4,  10, 7,  9,  5,  0,  15, 14, 2,  3,  12
}, {
13, 2,  8,  4,  6,  15, 11, 1,  10, 9,  3,  14, 5,  0,  12, 7,
1,  15, 13, 8,  10, 3,  7,  4,  12, 5,  6,  11, 0,  14, 9,  2,
7,  11, 4,  1,  9,  12, 14, 2,  0,  6,  10, 13, 15, 3,  5,  8,
2,  1,  14, 7,  4,  10, 8,  13, 15, 12, 9,  0,  3,  5,  6,  11
} };

// Permutation table
private static final byte[] P = {
16, 7,  20, 21,
29, 12, 28, 17,
1,  15, 23, 26,
5,  18, 31, 10,
2,  8,  24, 14,
32, 27, 3,  9,
19, 13, 30, 6,
22, 11, 4,  25
};

// Final permutation (aka Inverse permutation) table
private static final byte[] FP = {
40, 8, 48, 16, 56, 24, 64, 32,
39, 7, 47, 15, 55, 23, 63, 31,
38, 6, 46, 14, 54, 22, 62, 30,
37, 5, 45, 13, 53, 21, 61, 29,
36, 4, 44, 12, 52, 20, 60, 28,
35, 3, 43, 11, 51, 19, 59, 27,
34, 2, 42, 10, 50, 18, 58, 26,
33, 1, 41, 9, 49, 17, 57, 25
};

// 28 bits each, used as storage in the KS (Key Structure) rounds to
// generate round keys (aka subkeys)
private static int[] C = new int[28];
private static int[] D = new int[28];

// Decryption requires the 16 subkeys to be used in the exact same process
// as encryption, with the only difference being that the keys are used
// in reverse order, i.e. last key is used first and so on. Hence, during
// encryption when the keys are first generated, they are stored in this
// array. In case we wish to separate the encryption and decryption
// programs, then we need to generate the subkeys first in order, store
// them and then use them in reverse order.
private static int[][] subkey = new int[16][48];
/*private static String asciiToHex(String asciiValue)
``````

{
char[] chars = asciiValue.toCharArray();
StringBuffer hex = new StringBuffer();
for (int i = 0; i < chars.length; i++)
{
hex.append(Integer.toHexString((int) chars[i]));
}
return hex.toString();*/
}

``````public static void main(String args[]) {
System.out.println("Enter the input as a 16 character hexadecimal value:");
String input = new Scanner(System.in).nextLine();
int inputBits[] = new int[64];
// inputBits will store the 64 bits of the input as a an int array of
// size 64. This program uses int arrays to store bits, for the sake
// of simplicity. For efficient programming, use long data type. But
// it increases program complexity which is unnecessary for this
// context.
for(int i=0 ; i < 16 ; i++) {
// For every character in the 16 bit input, we get its binary value
// by first parsing it into an int and then converting to a binary
// string
String s = Integer.toBinaryString(Integer.parseInt(input.charAt(i) + "", 16));

// Java does not add padding zeros, i.e. 5 is returned as 111 but
// we require 0111. Hence, this while loop adds padding 0's to the
// binary value.
while(s.length() < 4) {
s = "0" + s;
}
// Add the 4 bits we have extracted into the array of bits.
for(int j=0 ; j < 4 ; j++) {
inputBits[(4*i)+j] = Integer.parseInt(s.charAt(j) + "");
}
}

// Similar process is followed for the 16 bit key
System.out.println("Enter the key as a 16 character hexadecimal value:");
String key = new Scanner(System.in).nextLine();
int keyBits[] = new int[64];
for(int i=0 ; i < 16 ; i++) {
String s = Integer.toBinaryString(Integer.parseInt(key.charAt(i) + "", 16));
while(s.length() < 4) {
s = "0" + s;
}
for(int j=0 ; j < 4 ; j++) {
keyBits[(4*i)+j] = Integer.parseInt(s.charAt(j) + "");
}
}

// permute(int[] inputBits, int[] keyBits, boolean isDecrypt)
// method is used here. This allows encryption and decryption to be
// done in the same method, reducing code.
System.out.println("\n+++ ENCRYPTION +++");
int outputBits[] = permute(inputBits, keyBits, false);
System.out.println("\n+++ DECRYPTION +++");
permute(outputBits, keyBits, true);
}

private static int[] permute(int[] inputBits, int[] keyBits, boolean isDecrypt) {
// Initial permutation step takes input bits and permutes into the
// newBits array
int newBits[] = new int[inputBits.length];
for(int i=0 ; i < inputBits.length ; i++) {
newBits[i] = inputBits[IP[i]-1];
}

// 16 rounds will start here
// L and R arrays are created to store the Left and Right halves of the
// subkey respectively
int L[] = new int[32];
int R[] = new int[32];
int i;

// Permuted Choice 1 is done here
for(i=0 ; i < 28 ; i++) {
C[i] = keyBits[PC1[i]-1];
}
for( ; i < 56 ; i++) {
D[i-28] = keyBits[PC1[i]-1];
}

// After PC1 the first L and R are ready to be used and hence looping
// can start once L and R are initialized
System.arraycopy(newBits, 0, L, 0, 32);
System.arraycopy(newBits, 32, R, 0, 32);
System.out.print("\nL0 = ");
displayBits(L);
System.out.print("R0 = ");
displayBits(R);
for(int n=0 ; n < 16 ; n++) {
System.out.println("\n-------------");
System.out.println("Round " + (n+1) + ":");
// newR is the new R half generated by the Fiestel function. If it
// is encrpytion then the KS method is called to generate the
// subkey otherwise the stored subkeys are used in reverse order
// for decryption.
int newR[] = new int[0];
if(isDecrypt) {
newR = fiestel(R, subkey[15-n]);
System.out.print("Round key = ");
displayBits(subkey[15-n]);
} else {
newR = fiestel(R, KS(n, keyBits));
System.out.print("Round key = ");
displayBits(subkey[n]);
}
// xor-ing the L and new R gives the new L value. new L is stored
// in R and new R is stored in L, thus exchanging R and L for the
// next round.
int newL[] = xor(L, newR);
L = R;
R = newL;
System.out.print("L = ");
displayBits(L);
System.out.print("R = ");
displayBits(R);
}

// R and L has the two halves of the output before applying the final
// permutation. This is called the "Preoutput".
int output[] = new int[64];
System.arraycopy(R, 0, output, 0, 32);
System.arraycopy(L, 0, output, 32, 32);
int finalOutput[] = new int[64];
// Applying FP table to the preoutput, we get the final output:
// Encryption => final output is ciphertext
// Decryption => final output is plaintext
for(i=0 ; i < 64 ; i++) {
finalOutput[i] = output[FP[i]-1];
}

// Since the final output is stored as an int array of bits, we convert
// it into a hex string:
String hex = new String();
for(i=0 ; i < 16 ; i++) {
String bin = new String();
for(int j=0 ; j < 4 ; j++) {
bin += finalOutput[(4*i)+j];
}
int decimal = Integer.parseInt(bin, 2);
hex += Integer.toHexString(decimal);
}
if(isDecrypt) {
System.out.print("Decrypted text: ");

} else {
System.out.print("Encrypted text: ");
}
System.out.println(hex.toUpperCase());
return finalOutput;
}

private static int[] KS(int round, int[] key) {
// The KS (Key Structure) function generates the round keys.
// C1 and D1 are the new values of C and D which will be generated in
// this round.
int C1[] = new int[28];
int D1[] = new int[28];

// The rotation array is used to set how many rotations are to be done
int rotationTimes = (int) rotations[round];
// leftShift() method is used for rotation (the rotation is basically)
// a left shift operation, hence the name.
C1 = leftShift(C, rotationTimes);
D1 = leftShift(D, rotationTimes);
// CnDn stores the combined C1 and D1 halves
int CnDn[] = new int[56];
System.arraycopy(C1, 0, CnDn, 0, 28);
System.arraycopy(D1, 0, CnDn, 28, 28);
// Kn stores the subkey, which is generated by applying the PC2 table
// to CnDn
int Kn[] = new int[48];
for(int i=0 ; i < Kn.length ; i++) {
Kn[i] = CnDn[PC2[i]-1];
}

// Now we store C1 and D1 in C and D respectively, thus becoming the
// old C and D for the next round. Subkey is stored and returned.
subkey[round] = Kn;
C = C1;
D = D1;
return Kn;
}

private static int[] fiestel(int[] R, int[] roundKey) {
// Method to implement Fiestel function.
// First the 32 bits of the R array are expanded using E table.
int expandedR[] = new int[48];
for(int i=0 ; i < 48 ; i++) {
expandedR[i] = R[E[i]-1];
}
// We xor the expanded R and the generated round key
int temp[] = xor(expandedR, roundKey);
// The S boxes are then applied to this xor result and this is the
// output of the Fiestel function.
int output[] = sBlock(temp);
return output;
}

private static int[] xor(int[] a, int[] b) {
// Simple xor function on two int arrays
for(int i=0 ; i < a.length ; i++) {
}
}

private static int[] sBlock(int[] bits) {
// S-boxes are applied in this method.
int output[] = new int[32];
// We know that input will be of 32 bits, hence we will loop 32/4 = 8
// times (divided by 4 as we will take 4 bits of input at each
// iteration).
for(int i=0 ; i < 8 ; i++) {
// S-box requires a row and a column, which is found from the
// input bits. The first and 6th bit of the current iteration
// (i.e. bits 0 and 5) gives the row bits.
int row[] = new int [2];
row[0] = bits[6*i];
row[1] = bits[(6*i)+5];
String sRow = row[0] + "" + row[1];
// Similarly column bits are found, which are the 4 bits between
// the two row bits (i.e. bits 1,2,3,4)
int column[] = new int[4];
column[0] = bits[(6*i)+1];
column[1] = bits[(6*i)+2];
column[2] = bits[(6*i)+3];
column[3] = bits[(6*i)+4];
String sColumn = column[0] +""+ column[1] +""+ column[2] +""+ column[3];
// Converting binary into decimal value, to be given into the
// array as input
int iRow = Integer.parseInt(sRow, 2);
int iColumn = Integer.parseInt(sColumn, 2);
int x = S[i][(iRow*16) + iColumn];
// We get decimal value of the S-box here, but we need to convert
// it into binary:
String s = Integer.toBinaryString(x);
// Padding is required since Java returns a decimal '5' as '111' in
// binary, when we require '0111'.
while(s.length() < 4) {
s = "0" + s;
}
// The binary bits are appended to the output
for(int j=0 ; j < 4 ; j++) {
output[(i*4) + j] = Integer.parseInt(s.charAt(j) + "");
}
}
// P table is applied to the output and this is the final output of one
// S-box round:
int finalOutput[] = new int[32];
for(int i=0 ; i < 32 ; i++) {
finalOutput[i] = output[P[i]-1];
}
return finalOutput;
}

private static int[] leftShift(int[] bits, int n) {
// Left shifting takes place here, i.e. each bit is rotated to the left
// and the leftmost bit is stored at the rightmost bit. This is a left
// shift operation.
for(int i=0 ; i < n ; i++) {
for(int j=0 ; j < bits.length-1 ; j++) {
}
}
}

private static void displayBits(int[] bits) {
// Method to display int array bits as a hexadecimal string.
for(int i=0 ; i < bits.length ; i+=4) {
String output = new String();
for(int j=0 ; j < 4 ; j++) {
output += bits[i+j];
}
System.out.print(Integer.toHexString(Integer.parseInt(output, 2)));
}
System.out.println();
}
``````

}

//