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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 1.8 and up. Note: this package includes the NTRU encryption algorithms.
package org.bouncycastle.math.ec.rfc8032;
import org.bouncycastle.util.Integers;
abstract class ScalarUtil
{
private static final long M = 0xFFFFFFFFL;
static void addShifted_NP(int last, int s, int[] Nu, int[] Nv, int[] _p)
{
int sWords = s >>> 5, sBits = s & 31;
long cc__p = 0L;
long cc_Nu = 0L;
if (sBits == 0)
{
for (int i = sWords; i <= last; ++i)
{
cc_Nu += Nu[i] & M;
cc_Nu += _p[i - sWords] & M;
cc__p += _p[i] & M;
cc__p += Nv[i - sWords] & M;
_p[i] = (int)cc__p; cc__p >>>= 32;
cc_Nu += _p[i - sWords] & M;
Nu[i] = (int)cc_Nu; cc_Nu >>>= 32;
}
}
else
{
int prev_p = 0;
int prev_q = 0;
int prev_v = 0;
for (int i = sWords; i <= last; ++i)
{
int next_p = _p[i - sWords];
int p_s = (next_p << sBits) | (prev_p >>> -sBits);
prev_p = next_p;
cc_Nu += Nu[i] & M;
cc_Nu += p_s & M;
int next_v = Nv[i - sWords];
int v_s = (next_v << sBits) | (prev_v >>> -sBits);
prev_v = next_v;
cc__p += _p[i] & M;
cc__p += v_s & M;
_p[i] = (int)cc__p; cc__p >>>= 32;
int next_q = _p[i - sWords];
int q_s = (next_q << sBits) | (prev_q >>> -sBits);
prev_q = next_q;
cc_Nu += q_s & M;
Nu[i] = (int)cc_Nu; cc_Nu >>>= 32;
}
}
}
static void addShifted_UV(int last, int s, int[] u0, int[] u1, int[] v0, int[] v1)
{
int sWords = s >>> 5, sBits = s & 31;
long cc_u0 = 0L;
long cc_u1 = 0L;
if (sBits == 0)
{
for (int i = sWords; i <= last; ++i)
{
cc_u0 += u0[i] & M;
cc_u1 += u1[i] & M;
cc_u0 += v0[i - sWords] & M;
cc_u1 += v1[i - sWords] & M;
u0[i] = (int)cc_u0; cc_u0 >>>= 32;
u1[i] = (int)cc_u1; cc_u1 >>>= 32;
}
}
else
{
int prev_v0 = 0;
int prev_v1 = 0;
for (int i = sWords; i <= last; ++i)
{
int next_v0 = v0[i - sWords];
int next_v1 = v1[i - sWords];
int v0_s = (next_v0 << sBits) | (prev_v0 >>> -sBits);
int v1_s = (next_v1 << sBits) | (prev_v1 >>> -sBits);
prev_v0 = next_v0;
prev_v1 = next_v1;
cc_u0 += u0[i] & M;
cc_u1 += u1[i] & M;
cc_u0 += v0_s & M;
cc_u1 += v1_s & M;
u0[i] = (int)cc_u0; cc_u0 >>>= 32;
u1[i] = (int)cc_u1; cc_u1 >>>= 32;
}
}
}
static int getBitLength(int last, int[] x)
{
int i = last;
int sign = x[i] >> 31;
while (i > 0 && x[i] == sign)
{
--i;
}
return i * 32 + 32 - Integers.numberOfLeadingZeros(x[i] ^ sign);
}
static int getBitLengthPositive(int last, int[] x)
{
int i = last;
while (i > 0 && x[i] == 0)
{
--i;
}
return i * 32 + 32 - Integers.numberOfLeadingZeros(x[i]);
}
static boolean lessThan(int last, int[] x, int[] y)
{
int i = last;
do
{
int x_i = x[i] + Integer.MIN_VALUE;
int y_i = y[i] + Integer.MIN_VALUE;
if (x_i < y_i)
return true;
if (x_i > y_i)
return false;
}
while (--i >= 0);
return false;
}
static void subShifted_NP(int last, int s, int[] Nu, int[] Nv, int[] _p)
{
int sWords = s >>> 5, sBits = s & 31;
long cc__p = 0L;
long cc_Nu = 0L;
if (sBits == 0)
{
for (int i = sWords; i <= last; ++i)
{
cc_Nu += Nu[i] & M;
cc_Nu -= _p[i - sWords] & M;
cc__p += _p[i] & M;
cc__p -= Nv[i - sWords] & M;
_p[i] = (int)cc__p; cc__p >>= 32;
cc_Nu -= _p[i - sWords] & M;
Nu[i] = (int)cc_Nu; cc_Nu >>= 32;
}
}
else
{
int prev_p = 0;
int prev_q = 0;
int prev_v = 0;
for (int i = sWords; i <= last; ++i)
{
int next_p = _p[i - sWords];
int p_s = (next_p << sBits) | (prev_p >>> -sBits);
prev_p = next_p;
cc_Nu += Nu[i] & M;
cc_Nu -= p_s & M;
int next_v = Nv[i - sWords];
int v_s = (next_v << sBits) | (prev_v >>> -sBits);
prev_v = next_v;
cc__p += _p[i] & M;
cc__p -= v_s & M;
_p[i] = (int)cc__p; cc__p >>= 32;
int next_q = _p[i - sWords];
int q_s = (next_q << sBits) | (prev_q >>> -sBits);
prev_q = next_q;
cc_Nu -= q_s & M;
Nu[i] = (int)cc_Nu; cc_Nu >>= 32;
}
}
}
static void subShifted_UV(int last, int s, int[] u0, int[] u1, int[] v0, int[] v1)
{
int sWords = s >>> 5, sBits = s & 31;
long cc_u0 = 0L;
long cc_u1 = 0L;
if (sBits == 0)
{
for (int i = sWords; i <= last; ++i)
{
cc_u0 += u0[i] & M;
cc_u1 += u1[i] & M;
cc_u0 -= v0[i - sWords] & M;
cc_u1 -= v1[i - sWords] & M;
u0[i] = (int)cc_u0; cc_u0 >>= 32;
u1[i] = (int)cc_u1; cc_u1 >>= 32;
}
}
else
{
int prev_v0 = 0;
int prev_v1 = 0;
for (int i = sWords; i <= last; ++i)
{
int next_v0 = v0[i - sWords];
int next_v1 = v1[i - sWords];
int v0_s = (next_v0 << sBits) | (prev_v0 >>> -sBits);
int v1_s = (next_v1 << sBits) | (prev_v1 >>> -sBits);
prev_v0 = next_v0;
prev_v1 = next_v1;
cc_u0 += u0[i] & M;
cc_u1 += u1[i] & M;
cc_u0 -= v0_s & M;
cc_u1 -= v1_s & M;
u0[i] = (int)cc_u0; cc_u0 >>= 32;
u1[i] = (int)cc_u1; cc_u1 >>= 32;
}
}
}
}