org.bouncycastle.math.ec.custom.sec.SecP256K1FieldElement Maven / Gradle / Ivy
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The FIPS 140-3 Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms certified to FIPS 140-3 level 1. This jar contains JCE provider and low-level API for the BC-FJA version 2.0.0, FIPS Certificate #4743. Please see certificate for certified platform details.
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/****** DO NOT EDIT THIS CLASS bc-java SOURCE FILE ******/
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package org.bouncycastle.math.ec.custom.sec;
import java.math.BigInteger;
import org.bouncycastle.math.ec.ECFieldElement;
import org.bouncycastle.math.internal.Mod;
import org.bouncycastle.math.internal.Nat256;
import org.bouncycastle.util.Arrays;
class SecP256K1FieldElement extends ECFieldElement.AbstractFp
{
public static final BigInteger Q = SecP256K1Curve.q;
protected int[] x;
public SecP256K1FieldElement(BigInteger x)
{
if (x == null || x.signum() < 0 || x.compareTo(Q) >= 0)
{
throw new IllegalArgumentException("x value invalid for SecP256K1FieldElement");
}
this.x = SecP256K1Field.fromBigInteger(x);
}
public SecP256K1FieldElement()
{
this.x = Nat256.create();
}
protected SecP256K1FieldElement(int[] x)
{
this.x = x;
}
public boolean isZero()
{
return Nat256.isZero(x);
}
public boolean isOne()
{
return Nat256.isOne(x);
}
public boolean testBitZero()
{
return Nat256.getBit(x, 0) == 1;
}
public BigInteger toBigInteger()
{
return Nat256.toBigInteger(x);
}
public String getFieldName()
{
return "SecP256K1Field";
}
public int getFieldSize()
{
return Q.bitLength();
}
public ECFieldElement add(ECFieldElement b)
{
int[] z = Nat256.create();
SecP256K1Field.add(x, ((SecP256K1FieldElement)b).x, z);
return new SecP256K1FieldElement(z);
}
public ECFieldElement addOne()
{
int[] z = Nat256.create();
SecP256K1Field.addOne(x, z);
return new SecP256K1FieldElement(z);
}
public ECFieldElement subtract(ECFieldElement b)
{
int[] z = Nat256.create();
SecP256K1Field.subtract(x, ((SecP256K1FieldElement)b).x, z);
return new SecP256K1FieldElement(z);
}
public ECFieldElement multiply(ECFieldElement b)
{
int[] z = Nat256.create();
SecP256K1Field.multiply(x, ((SecP256K1FieldElement)b).x, z);
return new SecP256K1FieldElement(z);
}
public ECFieldElement divide(ECFieldElement b)
{
// return multiply(b.invert());
int[] z = Nat256.create();
Mod.invert(SecP256K1Field.P, ((SecP256K1FieldElement)b).x, z);
SecP256K1Field.multiply(z, x, z);
return new SecP256K1FieldElement(z);
}
public ECFieldElement negate()
{
int[] z = Nat256.create();
SecP256K1Field.negate(x, z);
return new SecP256K1FieldElement(z);
}
public ECFieldElement square()
{
int[] z = Nat256.create();
SecP256K1Field.square(x, z);
return new SecP256K1FieldElement(z);
}
public ECFieldElement invert()
{
// return new SecP256K1FieldElement(toBigInteger().modInverse(Q));
int[] z = Nat256.create();
Mod.invert(SecP256K1Field.P, x, z);
return new SecP256K1FieldElement(z);
}
// D.1.4 91
/**
* return a sqrt root - the routine verifies that the calculation returns the right value - if
* none exists it returns null.
*/
public ECFieldElement sqrt()
{
/*
* Raise this element to the exponent 2^254 - 2^30 - 2^7 - 2^6 - 2^5 - 2^4 - 2^2
*
* Breaking up the exponent's binary representation into "repunits", we get:
* { 223 1s } { 1 0s } { 22 1s } { 4 0s } { 2 1s } { 2 0s}
*
* Therefore we need an addition chain containing 2, 22, 223 (the lengths of the repunits)
* We use: 1, [2], 3, 6, 9, 11, [22], 44, 88, 176, 220, [223]
*/
int[] x1 = this.x;
if (Nat256.isZero(x1) || Nat256.isOne(x1))
{
return this;
}
int[] x2 = Nat256.create();
SecP256K1Field.square(x1, x2);
SecP256K1Field.multiply(x2, x1, x2);
int[] x3 = Nat256.create();
SecP256K1Field.square(x2, x3);
SecP256K1Field.multiply(x3, x1, x3);
int[] x6 = Nat256.create();
SecP256K1Field.squareN(x3, 3, x6);
SecP256K1Field.multiply(x6, x3, x6);
int[] x9 = x6;
SecP256K1Field.squareN(x6, 3, x9);
SecP256K1Field.multiply(x9, x3, x9);
int[] x11 = x9;
SecP256K1Field.squareN(x9, 2, x11);
SecP256K1Field.multiply(x11, x2, x11);
int[] x22 = Nat256.create();
SecP256K1Field.squareN(x11, 11, x22);
SecP256K1Field.multiply(x22, x11, x22);
int[] x44 = x11;
SecP256K1Field.squareN(x22, 22, x44);
SecP256K1Field.multiply(x44, x22, x44);
int[] x88 = Nat256.create();
SecP256K1Field.squareN(x44, 44, x88);
SecP256K1Field.multiply(x88, x44, x88);
int[] x176 = Nat256.create();
SecP256K1Field.squareN(x88, 88, x176);
SecP256K1Field.multiply(x176, x88, x176);
int[] x220 = x88;
SecP256K1Field.squareN(x176, 44, x220);
SecP256K1Field.multiply(x220, x44, x220);
int[] x223 = x44;
SecP256K1Field.squareN(x220, 3, x223);
SecP256K1Field.multiply(x223, x3, x223);
int[] t1 = x223;
SecP256K1Field.squareN(t1, 23, t1);
SecP256K1Field.multiply(t1, x22, t1);
SecP256K1Field.squareN(t1, 6, t1);
SecP256K1Field.multiply(t1, x2, t1);
SecP256K1Field.squareN(t1, 2, t1);
int[] t2 = x2;
SecP256K1Field.square(t1, t2);
return Nat256.eq(x1, t2) ? new SecP256K1FieldElement(t1) : null;
}
public boolean equals(Object other)
{
if (other == this)
{
return true;
}
if (!(other instanceof SecP256K1FieldElement))
{
return false;
}
SecP256K1FieldElement o = (SecP256K1FieldElement)other;
return Nat256.eq(x, o.x);
}
public int hashCode()
{
return Q.hashCode() ^ Arrays.hashCode(x, 0, 8);
}
}