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
	int answer[] = new int[a.length];
	for(int i=0 ; i < a.length ; i++) {
		answer[i] = a[i]^b[i];
	}
	return answer;
}

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.
	int answer[] = new int[bits.length];
	System.arraycopy(bits, 0, answer, 0, bits.length);
	for(int i=0 ; i < n ; i++) {
		int temp = answer[0];
		for(int j=0 ; j < bits.length-1 ; j++) {
			answer[j] = answer[j+1];
		}
		answer[bits.length-1] = temp;
	}
	return answer;
}

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();
}

}

//