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@manusreload
Created April 4, 2015 12:38
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Random Scramble
public class Scramble {
public static final int SIZE = 624;
int seed;
int[] buffer = new int[SIZE];
int ix = 0;
public Scramble(int seed) {
this.seed = seed;
for (int i = 0; i < 624; i++) {
buffer[i] = seed;
seed = 1812433253 * ((seed ^ (seed >> 30)) + 1) & 0xFFFFFFFF;
}
}
public byte[] getScramble(byte[] serverRandom)
{
// String result = "";
byte[] result = new byte[serverRandom.length];
byte byte100 = 0;
for (int i = 0; i < 100; i++) {
byte100 = getByte();
}
for (int i = 0; i < serverRandom.length; i++) {
byte b = (byte) (getByte() & byte100);
result [i] = ((byte) (serverRandom[i] ^ b));
}
return result;
}
private byte getByte()
{
int x = getInt();
if(isNeg(x))
{
x = negate(x);
}
return (byte) (x);
}
private int getInt()
{
if(ix == 0)
{
mixBuffer();
}
int val = buffer[ix];
ix = (ix+1) % 624;
val ^= (val >> 11) ^ ((val ^ (val >> 11)) << 7) & 0x9D2C5680;
val = (int) (((val ^ (val << 15) & 0xEFC60000) >> 18) ^ val ^ (val << 15) & 0xEFC60000);
return val;
}
private void mixBuffer()
{
// while i<624:
// i += 1
// v4= (self.buffer[i%624] & 0x7FFFFFFF) + (self.buffer[j]&0x80000000)
// v6 = rshift(v4,1) ^ self.buffer[(i+396)%624]
// if v4&1:
// v6 ^= 0x9908B0DF
// self.buffer[j] = v6
// j += 1
for (int i = 1, j = 0; i <= SIZE; i++, j++) {
int v4 = (buffer[i % SIZE] & 0x7FFFFFFF) + (buffer[j] & 0x80000000);
int v6 = (v4 >> 1) ^ buffer[(i + 396) % 624];
if( (v4 & 1) == 1 )
{
v6 ^= 0x9908B0DF;
}
buffer[j] = v6;
}
}
private void dumpbuffer()
{
for (int c : buffer) {
System.out.println(String.format("%08x", c));
}
}
private boolean isNeg(int number)
{
return Integer.signum(number) == -1;
}
private int negate(int number)
{
return Integer.reverse(number) >> 8;
}
}
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