jdk/src/java.base/share/classes/sun/security/util/math/IntegerModuloP.java
Volodymyr Paprotski f12710e938 8288047: Accelerate Poly1305 on x86_64 using AVX512 instructions
Reviewed-by: sviswanathan, vlivanov
2022-11-21 21:01:25 +00:00

416 lines
15 KiB
Java

/*
* Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package sun.security.util.math;
import sun.security.util.math.intpoly.IntegerPolynomialP256;
import sun.security.util.math.intpoly.P256OrderField;
import java.math.BigInteger;
/**
* The base interface for integers modulo a prime value. Objects of this
* type may be either mutable or immutable, and subinterfaces can be used
* to specify that an object is mutable or immutable. This type should never
* be used to declare local/member variables, but it may be used for
* formal parameters of a method. None of the methods in this interface
* modify the value of arguments or this.
*
* The behavior of this interface depends on the particular implementation.
* For example, some implementations only support a limited number of add
* operations before each multiply operation. See the documentation of the
* implementation for details.
*
* @see ImmutableIntegerModuloP
* @see MutableIntegerModuloP
*/
public interface IntegerModuloP {
/**
* Get the field associated with this element.
*
* @return the field
*/
IntegerFieldModuloP getField();
/**
* Get the canonical value of this element as a BigInteger. This value
* will always be in the range [0, p), where p is the prime that defines
* the field. This method performs reduction and other computation to
* produce the result.
*
* @return the value as a BigInteger
*/
BigInteger asBigInteger();
/**
* Return this value as a fixed (immutable) element. This method will
* copy the underlying representation if the object is mutable.
*
* @return a fixed element with the same value
*/
ImmutableIntegerModuloP fixed();
/**
* Return this value as a mutable element. This method will always copy
* the underlying representation.
*
* @return a mutable element with the same value
*/
MutableIntegerModuloP mutable();
/**
* Add this field element with the supplied element and return the result.
*
* @param b the sumand
* @return this + b
*/
ImmutableIntegerModuloP add(IntegerModuloP b);
/**
* Compute the additive inverse of the field element
* @return the addditiveInverse (0 - this)
*/
ImmutableIntegerModuloP additiveInverse();
/**
* Multiply this field element with the supplied element and return the
* result.
*
* @param b the multiplicand
* @return this * b
*/
ImmutableIntegerModuloP multiply(IntegerModuloP b);
/**
* Perform an addition modulo a power of two and return the little-endian
* encoding of the result. The value is (this' + b') % 2^(8 * len),
* where this' and b' are the canonical integer values equivalent to
* this and b.
*
* @param b the sumand
* @param len the length of the desired array
* @return a byte array of length len containing the result
*/
default byte[] addModPowerTwo(IntegerModuloP b, int len) {
byte[] result = new byte[len];
addModPowerTwo(b, result);
return result;
}
/**
* Perform an addition modulo a power of two and store the little-endian
* encoding of the result in the supplied array. The value is
* (this' + b') % 2^(8 * result.length), where this' and b' are the
* canonical integer values equivalent to this and b.
*
* @param b the sumand
* @param result an array which stores the result upon return
*/
void addModPowerTwo(IntegerModuloP b, byte[] result);
/**
* Returns the little-endian encoding of this' % 2^(8 * len), where this'
* is the canonical integer value equivalent to this.
*
* @param len the length of the desired array
* @return a byte array of length len containing the result
*/
default byte[] asByteArray(int len) {
byte[] result = new byte[len];
asByteArray(result);
return result;
}
/**
* Places the little-endian encoding of this' % 2^(8 * result.length)
* into the supplied array, where this' is the canonical integer value
* equivalent to this.
*
* @param result an array which stores the result upon return
*/
void asByteArray(byte[] result);
/**
* Break encapsulation, used for IntrinsicCandidate functions
*/
long[] getLimbs();
/**
* Compute the multiplicative inverse of this field element.
*
* @return the multiplicative inverse (1 / this)
*/
default ImmutableIntegerModuloP multiplicativeInverse() {
// This method is used in 2 cases:
// 1. To calculate the inverse of a number in ECDSAOperations,
// this number must be non-zero (modulo p).
// 2. To flatten a 3D point to a 2D AffinePoint. This number
// might be zero (infinity). However, since the infinity
// is represented as (0, 0) in 2D, it's OK returning 0 as
// the inverse of 0, i.e. (1, 1, 0) == (1/0, 1/0) == (0, 0).
return MultiplicativeInverser.of(getField().getSize()).inverse(this);
}
/**
* Subtract the supplied element from this one and return the result.
* @param b the subtrahend
*
* @return the difference (this - b)
*/
default ImmutableIntegerModuloP subtract(IntegerModuloP b) {
return add(b.additiveInverse());
}
/**
* Calculate the square of this element and return the result. This method
* should be used instead of a.multiply(a) because implementations may
* include optimizations that only apply to squaring.
*
* @return the product (this * this)
*/
default ImmutableIntegerModuloP square() {
return multiply(this);
}
/**
* Calculate the power this^b and return the result.
*
* @param b the exponent
* @return the value of this^b
*/
default ImmutableIntegerModuloP pow(BigInteger b) {
//Default implementation is square and multiply
MutableIntegerModuloP y = getField().get1().mutable();
MutableIntegerModuloP x = mutable();
int bitLength = b.bitLength();
for (int bit = 0; bit < bitLength; bit++) {
if (b.testBit(bit)) {
// odd
y.setProduct(x);
}
x.setSquare();
}
return y.fixed();
}
sealed interface MultiplicativeInverser {
static MultiplicativeInverser of(BigInteger m) {
if (m.equals(IntegerPolynomialP256.MODULUS)) {
return Secp256R1.instance;
} else if (m.equals(P256OrderField.MODULUS)) {
return Secp256R1Field.instance;
} else {
return new Default(m);
}
}
/**
* Compute the multiplicative inverse of {@code imp}.
*
* @return the multiplicative inverse (1 / imp)
*/
ImmutableIntegerModuloP inverse(IntegerModuloP imp);
final class Default implements MultiplicativeInverser {
private final BigInteger b;
Default(BigInteger b) {
this.b = b.subtract(BigInteger.TWO);
}
@Override
public ImmutableIntegerModuloP inverse(IntegerModuloP imp) {
MutableIntegerModuloP y = imp.getField().get1().mutable();
MutableIntegerModuloP x = imp.mutable();
int bitLength = b.bitLength();
for (int bit = 0; bit < bitLength; bit++) {
if (b.testBit(bit)) {
// odd
y.setProduct(x);
}
x.setSquare();
}
return y.fixed();
}
}
final class Secp256R1 implements MultiplicativeInverser {
private static final Secp256R1 instance = new Secp256R1();
@Override
public ImmutableIntegerModuloP inverse(IntegerModuloP imp) {
// Invert imp with a modular exponentiation: the modulus is
// p = FFFFFFFF 00000001 00000000 00000000
// 00000000 FFFFFFFF FFFFFFFF FFFFFFFF
// and the exponent is (p -2).
// p -2 = FFFFFFFF 00000001 00000000 00000000
// 00000000 FFFFFFFF FFFFFFFF FFFFFFFD
//
// There are 3 contiguous 32-bit set, and 1 contiguous 30-bit
// set. Thus values imp^(2^32 - 1) and imp^(2^30 - 1) are
// pre-computed to speed up the computation.
// calculate imp ^ (2^32 - 1)
MutableIntegerModuloP t = imp.mutable();
MutableIntegerModuloP v = null;
MutableIntegerModuloP w = null;
for (int i = 0; i < 31; i++) {
t.setSquare();
switch (i) {
case 0 -> {
t.setProduct(imp);
v = t.mutable(); // 2: imp ^ (2^2 - 1)
}
case 4 -> {
t.setProduct(v);
w = t.mutable(); // 4: imp ^ (2^6 - 1)
}
case 12, 28 -> {
t.setProduct(w);
w = t.mutable(); // 12: imp ^ (2^14 - 1)
// 28: imp ^ (2^30 - 1)
}
case 2, 6, 14, 30 -> {
t.setProduct(v);
}
}
}
// here we have:
// v = imp ^ (2^2 - 1)
// w = imp ^ (2^30 - 1)
// t = imp ^ (2^32 - 1)
// calculate (1 / imp)
MutableIntegerModuloP d = t.mutable();
for (int i = 32; i < 256; i++) {
d.setSquare();
switch (i) {
// For contiguous 32-bit set.
case 191, 223 -> {
d.setProduct(t);
}
// For contiguous 30-bit set.
case 253 -> {
d.setProduct(w);
}
// For individual 1-bit set.
case 63, 255 -> {
d.setProduct(imp);
}
}
}
return d.fixed();
}
}
final class Secp256R1Field implements MultiplicativeInverser {
private static final Secp256R1Field instance = new Secp256R1Field();
private static final BigInteger b =
P256OrderField.MODULUS.subtract(BigInteger.TWO);
@Override
public ImmutableIntegerModuloP inverse(IntegerModuloP imp) {
// Invert imp with a modular exponentiation: the modulus is
// n = FFFFFFFF 00000000 FFFFFFFF FFFFFFFF
// BCE6FAAD A7179E84 F3B9CAC2 FC632551
// and the exponent is (n -2).
// n - 2 = FFFFFFFF 00000000 FFFFFFFF FFFFFFFF
// BCE6FAAD A7179E84 F3B9CAC2 FC63254F
//
// There are 3 contiguous 32-bit set, and imp^(2^32 - 1)
// is pre-computed to speed up the computation.
// calculate and cache imp ^ (2^2 - 1) - imp ^ (2^4 - 1)
IntegerModuloP[] w = new IntegerModuloP[4];
w[0] = imp.fixed();
MutableIntegerModuloP t = imp.mutable();
for (int i = 1; i < 4; i++) {
t.setSquare();
t.setProduct(imp);
w[i] = t.fixed();
}
// calculate imp ^ (2^32 - 1)
MutableIntegerModuloP d = null;
for (int i = 4; i < 32; i++) {
t.setSquare();
switch (i) {
case 7 -> {
t.setProduct(w[3]);
d = t.mutable(); // 7: imp ^ (2^8 - 1)
}
case 15 -> {
t.setProduct(d);
d = t.mutable(); // 15: imp ^ (2^16 - 1)
}
case 31 -> {
t.setProduct(d); // 31: imp ^ (2^32 - 1)
}
}
}
// Here we have:
// w[i] = imp ^ (2 ^ ( i + 1) - 1), i = {0, 1, 2, 3}
// t = imp ^ (2^32 - 1)
//
// calculate for bit 32-128, for contiguous 32-bit set.
d = t.mutable();
for (int i = 32; i < 128; i++) {
d.setSquare();
if (i == 95 || i == 127) {
d.setProduct(t);
}
}
// Calculate for bit 128-255, for individual 1-bit set.
for (int k = -1, i = 127; i >= 0; i--) {
if (b.testBit(i)) {
if (k == w.length - 2) {
// calculate the current & reserved bits
d.setSquare();
d.setProduct(w[w.length - 1]);
k = -1;
} else {
k++;
d.setSquare();
}
} else { // calculate the reserved bits
if (k >= 0) {
// add back the reserved bits
d.setProduct(w[k]);
k = -1;
}
d.setSquare();
}
}
return d.fixed();
}
}
}
}