public class Crypt {
static int sub[] = new int[48];

// TABLES
/* Expansion table (32 to 48) */
int E_p[] = { 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 };

/* Permutation Choice 1 for subkey generation (64/56 to 56) */
int PC1_p[] = { 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 };

/* Permutation Choice 2 for subkey generation (56 to 48) */
int PC2_p[] = { 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 };

/* Number of rotations for the iteration of key scheduling */
/* The concept of a table here doesn't fit our behavioral model */
/* This will be logic in our final design */
int keyrots[] = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 };

/*
* Selection blocks There are 8 sblocks, each of which is referenced by a 2
* bit value which picks the row, and a 4 bit value which picks the column
* This number is then the 4 bit output for that select block
*/
int sblocks[][][] = {
{ { 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 P for after sblocks */
int P_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 };

/*
* Inverse permutation of IP for end Temporary - the true behavior will be
* implemented in a shift out register (Look at the pattern obvious in an
* 8x8 layout)
*/
int IPinv_p[] = { 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 };

// CODE
private void pr_bits(int[] s, int amt) {
amt /= 8;
for (int i = 0; i < amt; i++) {
int x = 0;
for (int j = 0; j < 8; j++)
x |= s[i * 8 + j] << (7 - j);
Integer integ = new Integer(x);
System.out.print(integ.toString(x, 16) + " ");
}
System.out.println();
};

private void permute(int[] by, int amt, int[] in, int[] out) {
for (; --amt >= 0;)
out[amt] = in[by[amt] - 1];
};

private void do_sblocks(int[] in, int[] out) {
for (int i = 0; i < 8; i++) {
int val = sblocks[i][in[i * 6] << 1 | in[i * 6 + 5]][in[i * 6 + 1] << 3
| in[i * 6 + 2] << 2
| in[i * 6 + 3] << 1
| in[i * 6 + 4] << 0];
out[i * 4 + 0] = val >> 3 & 1;
out[i * 4 + 1] = val >> 2 & 1;
out[i * 4 + 2] = val >> 1 & 1;
out[i * 4 + 3] = val >> 0 & 1;
}
};

private int ascii_to_bin(char c) {
if (c >= 'a')
return (c - 59);
if (c >= 'A')
return (c - 53);
return (c - '.');
};

private char bin_to_ascii(int c) {
if (c >= 38)
return (char) (c - 38 + 'a');
if (c >= 12)
return (char) (c - 12 + 'A');
return (char) (c + '.');
};

private void load_salt(int[] saltmask, char[] salt) {
int tot = ascii_to_bin(salt[0]) | (ascii_to_bin(salt[1]) << 6);
for (int i = 0; i < 12; i++)
saltmask[i] = tot >> i & 1;
};

private void do_salt(int[] bits, int[] saltmask) {
for (int i = 0; i < 12; i++)
if (saltmask[i] != 0) {
int t = bits[i];
bits[i] = bits[24 + i];
bits[24 + i] = t;
}
};

private void load_key(int[] ikey, char[] password) {
int tmp[] = new int[64];

for (int i = 0; i < 8; i++)
for (int j = 0; j < 8; j++)
tmp[i * 8 + j] = (password[i] >> (6 - j)) & 1;
permute(PC1_p, 56, tmp, ikey);
};

private void subkey(int[] ikey, int iter) {
int rots = keyrots[iter];

int tmp0l = ikey[0];
int tmp1l = ikey[1];
int tmp0r = ikey[28];
int tmp1r = ikey[29];
for (int i = 0; i < 28 - rots; i++) {
ikey[i] = ikey[i + rots];
ikey[28 + i] = ikey[28 + i + rots];
}
if (rots == 2) {
ikey[26] = tmp0l;
ikey[27] = tmp1l;
ikey[54] = tmp0r;
ikey[55] = tmp1r;
} else {
ikey[27] = tmp0l;
ikey[55] = tmp0r;
}

permute(PC2_p, 48, ikey, sub);
};

private void xor(int[] src1, int[] src2, int index, int num) {
for (int i = 0; i < num; i++)
src1[i] = (src1[i] ^ src2[index + i]) & 1;
};

private void print_bits(int[] s, int amt) {
for (int i = 0; i < amt; i++)
System.out.print("" + s[i]);
System.out.println("");
};

private void do_f(int[] in, int index, int[] out, int iter, int[] ikey,
int[] saltmask) {
int tmp48[] = new int[48], tmp32[] = new int[32], skey[];

for (int i = 0; i < 32; i++)
tmp32[i] = in[i + index];
permute(E_p, 48, tmp32, tmp48);
do_salt(tmp48, saltmask);

subkey(ikey, iter);
skey = sub;
xor(tmp48, skey, 0, 48); // Goed
do_sblocks(tmp48, tmp32);
permute(P_p, 32, tmp32, out);
};

private char[] mycrypt(char[] password, char[] salt) {
int bits[] = new int[64];
int outl[] = new int[32];
int outr[] = new int[32];
int done[] = new int[66]; // In c-code array-size was 64 !?!
int ikey[] = new int[56];
int saltmask[] = new int[12];
char[] answer = new char[14];

for (int i = 0; i < 64; i++)
bits[i] = 0;
load_key(ikey, password);
load_salt(saltmask, salt);

for (int dess = 0; dess < 25; dess++) {
for (int iters = 0; iters < 16; iters += 2) {
do_f(bits, 32, outl, iters, ikey, saltmask);
xor(outl, bits, 0, 32);
do_f(outl, 0, outr, iters + 1, ikey, saltmask);
xor(outr, bits, 32, 32);

if (iters != 14)
for (int i = 0; i < 32; i++) {
bits[i] = outl[i];
bits[i + 32] = outr[i];
}
else
for (int i = 0; i < 32; i++) {
bits[i] = outr[i];
bits[i + 32] = outl[i];
}
}
}
permute(IPinv_p, 64, bits, done);

answer[0] = (char) salt[0];
answer[1] = (char) salt[1];
for (int i = 0; i < 11; i++) {
char c = 0;
for (int j = 0; j < 6; j++)
c |= done[6 * i + j] << (5 - j);
answer[i + 2] = bin_to_ascii(c);
}
return answer;
};

/**
* This method decodes the given password Encryption is based on the one way
* DES encryption
*
* @return The encrypted password
* @param passwd
* is the password to encrypt
* @param s
* is salt
*/
public String decode(String passwd, String s) {
char[] password = new char[9];
char[] salt = new char[3];
String uitkomst;

passwd.getChars(0, passwd.length() >= 8 ? 8 : passwd.length(),
password, 0);
s.getChars(0, 2, salt, 0);

uitkomst = new String().valueOf(mycrypt(password, salt));
return (uitkomst.substring(0, 13));
}

public static void main(String[] args){
Crypt crypt = new Crypt();
System.out.println(crypt.decode("kent", "ke")); }

}