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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.4. Note: this package includes the NTRU encryption algorithms.
package org.bouncycastle.crypto.modes.gcm;
import org.bouncycastle.util.Pack;
public abstract class GCMUtil
{
private static final int E1 = 0xe1000000;
private static final long E1L = (E1 & 0xFFFFFFFFL) << 32;
private static int[] generateLookup()
{
int[] lookup = new int[256];
for (int c = 0; c < 256; ++c)
{
int v = 0;
for (int i = 7; i >= 0; --i)
{
if ((c & (1 << i)) != 0)
{
v ^= (E1 >>> (7 - i));
}
}
lookup[c] = v;
}
return lookup;
}
private static final int[] LOOKUP = generateLookup();
public static byte[] oneAsBytes()
{
byte[] tmp = new byte[16];
tmp[0] = (byte)0x80;
return tmp;
}
public static int[] oneAsInts()
{
int[] tmp = new int[4];
tmp[0] = 1 << 31;
return tmp;
}
public static long[] oneAsLongs()
{
long[] tmp = new long[2];
tmp[0] = 1L << 63;
return tmp;
}
public static byte[] asBytes(int[] x)
{
byte[] z = new byte[16];
Pack.intToBigEndian(x, z, 0);
return z;
}
public static void asBytes(int[] x, byte[] z)
{
Pack.intToBigEndian(x, z, 0);
}
public static byte[] asBytes(long[] x)
{
byte[] z = new byte[16];
Pack.longToBigEndian(x, z, 0);
return z;
}
public static void asBytes(long[] x, byte[] z)
{
Pack.longToBigEndian(x, z, 0);
}
public static int[] asInts(byte[] x)
{
int[] z = new int[4];
Pack.bigEndianToInt(x, 0, z);
return z;
}
public static void asInts(byte[] x, int[] z)
{
Pack.bigEndianToInt(x, 0, z);
}
public static long[] asLongs(byte[] x)
{
long[] z = new long[2];
Pack.bigEndianToLong(x, 0, z);
return z;
}
public static void asLongs(byte[] x, long[] z)
{
Pack.bigEndianToLong(x, 0, z);
}
public static void multiply(byte[] x, byte[] y)
{
int[] t1 = GCMUtil.asInts(x);
int[] t2 = GCMUtil.asInts(y);
GCMUtil.multiply(t1, t2);
GCMUtil.asBytes(t1, x);
}
public static void multiply(int[] x, int[] y)
{
int r00 = x[0], r01 = x[1], r02 = x[2], r03 = x[3];
int r10 = 0, r11 = 0, r12 = 0, r13 = 0;
for (int i = 0; i < 4; ++i)
{
int bits = y[i];
for (int j = 0; j < 32; ++j)
{
int m1 = bits >> 31; bits <<= 1;
r10 ^= (r00 & m1);
r11 ^= (r01 & m1);
r12 ^= (r02 & m1);
r13 ^= (r03 & m1);
int m2 = (r03 << 31) >> 8;
r03 = (r03 >>> 1) | (r02 << 31);
r02 = (r02 >>> 1) | (r01 << 31);
r01 = (r01 >>> 1) | (r00 << 31);
r00 = (r00 >>> 1) ^ (m2 & E1);
}
}
x[0] = r10;
x[1] = r11;
x[2] = r12;
x[3] = r13;
}
public static void multiply(long[] x, long[] y)
{
long r00 = x[0], r01 = x[1], r10 = 0, r11 = 0;
for (int i = 0; i < 2; ++i)
{
long bits = y[i];
for (int j = 0; j < 64; ++j)
{
long m1 = bits >> 63; bits <<= 1;
r10 ^= (r00 & m1);
r11 ^= (r01 & m1);
long m2 = (r01 << 63) >> 8;
r01 = (r01 >>> 1) | (r00 << 63);
r00 = (r00 >>> 1) ^ (m2 & E1L);
}
}
x[0] = r10;
x[1] = r11;
}
// P is the value with only bit i=1 set
public static void multiplyP(int[] x)
{
int m = shiftRight(x) >> 8;
x[0] ^= (m & E1);
}
public static void multiplyP(int[] x, int[] z)
{
int m = shiftRight(x, z) >> 8;
z[0] ^= (m & E1);
}
// P is the value with only bit i=1 set
public static void multiplyP8(int[] x)
{
// for (int i = 8; i != 0; --i)
// {
// multiplyP(x);
// }
int c = shiftRightN(x, 8);
x[0] ^= LOOKUP[c >>> 24];
}
public static void multiplyP8(int[] x, int[] y)
{
int c = shiftRightN(x, 8, y);
y[0] ^= LOOKUP[c >>> 24];
}
static int shiftRight(int[] x)
{
// int c = 0;
// for (int i = 0; i < 4; ++i)
// {
// int b = x[i];
// x[i] = (b >>> 1) | c;
// c = b << 31;
// }
// return c;
int b = x[0];
x[0] = b >>> 1;
int c = b << 31;
b = x[1];
x[1] = (b >>> 1) | c;
c = b << 31;
b = x[2];
x[2] = (b >>> 1) | c;
c = b << 31;
b = x[3];
x[3] = (b >>> 1) | c;
return b << 31;
}
static int shiftRight(int[] x, int[] z)
{
// int c = 0;
// for (int i = 0; i < 4; ++i)
// {
// int b = x[i];
// z[i] = (b >>> 1) | c;
// c = b << 31;
// }
// return c;
int b = x[0];
z[0] = b >>> 1;
int c = b << 31;
b = x[1];
z[1] = (b >>> 1) | c;
c = b << 31;
b = x[2];
z[2] = (b >>> 1) | c;
c = b << 31;
b = x[3];
z[3] = (b >>> 1) | c;
return b << 31;
}
static long shiftRight(long[] x)
{
long b = x[0];
x[0] = b >>> 1;
long c = b << 63;
b = x[1];
x[1] = (b >>> 1) | c;
return b << 63;
}
static long shiftRight(long[] x, long[] z)
{
long b = x[0];
z[0] = b >>> 1;
long c = b << 63;
b = x[1];
z[1] = (b >>> 1) | c;
return b << 63;
}
static int shiftRightN(int[] x, int n)
{
// int c = 0, nInv = 32 - n;
// for (int i = 0; i < 4; ++i)
// {
// int b = x[i];
// x[i] = (b >>> n) | c;
// c = b << nInv;
// }
// return c;
int b = x[0], nInv = 32 - n;
x[0] = b >>> n;
int c = b << nInv;
b = x[1];
x[1] = (b >>> n) | c;
c = b << nInv;
b = x[2];
x[2] = (b >>> n) | c;
c = b << nInv;
b = x[3];
x[3] = (b >>> n) | c;
return b << nInv;
}
static int shiftRightN(int[] x, int n, int[] z)
{
// int c = 0, nInv = 32 - n;
// for (int i = 0; i < 4; ++i)
// {
// int b = x[i];
// z[i] = (b >>> n) | c;
// c = b << nInv;
// }
// return c;
int b = x[0], nInv = 32 - n;
z[0] = b >>> n;
int c = b << nInv;
b = x[1];
z[1] = (b >>> n) | c;
c = b << nInv;
b = x[2];
z[2] = (b >>> n) | c;
c = b << nInv;
b = x[3];
z[3] = (b >>> n) | c;
return b << nInv;
}
public static void xor(byte[] x, byte[] y)
{
int i = 0;
do
{
x[i] ^= y[i]; ++i;
x[i] ^= y[i]; ++i;
x[i] ^= y[i]; ++i;
x[i] ^= y[i]; ++i;
}
while (i < 16);
}
public static void xor(byte[] x, byte[] y, int yOff, int yLen)
{
while (--yLen >= 0)
{
x[yLen] ^= y[yOff + yLen];
}
}
public static void xor(byte[] x, byte[] y, byte[] z)
{
int i = 0;
do
{
z[i] = (byte)(x[i] ^ y[i]); ++i;
z[i] = (byte)(x[i] ^ y[i]); ++i;
z[i] = (byte)(x[i] ^ y[i]); ++i;
z[i] = (byte)(x[i] ^ y[i]); ++i;
}
while (i < 16);
}
public static void xor(int[] x, int[] y)
{
x[0] ^= y[0];
x[1] ^= y[1];
x[2] ^= y[2];
x[3] ^= y[3];
}
public static void xor(int[] x, int[] y, int[] z)
{
z[0] = x[0] ^ y[0];
z[1] = x[1] ^ y[1];
z[2] = x[2] ^ y[2];
z[3] = x[3] ^ y[3];
}
public static void xor(long[] x, long[] y)
{
x[0] ^= y[0];
x[1] ^= y[1];
}
public static void xor(long[] x, long[] y, long[] z)
{
z[0] = x[0] ^ y[0];
z[1] = x[1] ^ y[1];
}
}