86 lines
3.7 KiB
Java
86 lines
3.7 KiB
Java
package org.bouncycastle.asn1.ua;
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import java.math.BigInteger;
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import java.util.Random;
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import org.bouncycastle.math.ec.ECConstants;
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import org.bouncycastle.math.ec.ECCurve;
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import org.bouncycastle.math.ec.ECFieldElement;
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import org.bouncycastle.math.ec.ECPoint;
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/* loaded from: classes6.dex */
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public abstract class DSTU4145PointEncoder {
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private static ECFieldElement trace(ECFieldElement eCFieldElement) {
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ECFieldElement eCFieldElement2 = eCFieldElement;
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for (int i = 1; i < eCFieldElement.getFieldSize(); i++) {
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eCFieldElement2 = eCFieldElement2.square().add(eCFieldElement);
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}
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return eCFieldElement2;
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}
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private static ECFieldElement solveQuadraticEquation(ECCurve eCCurve, ECFieldElement eCFieldElement) {
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ECFieldElement eCFieldElement2;
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if (eCFieldElement.isZero()) {
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return eCFieldElement;
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}
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ECFieldElement fromBigInteger = eCCurve.fromBigInteger(ECConstants.ZERO);
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Random random = new Random();
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int fieldSize = eCFieldElement.getFieldSize();
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do {
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ECFieldElement fromBigInteger2 = eCCurve.fromBigInteger(new BigInteger(fieldSize, random));
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ECFieldElement eCFieldElement3 = eCFieldElement;
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eCFieldElement2 = fromBigInteger;
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for (int i = 1; i <= fieldSize - 1; i++) {
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ECFieldElement square = eCFieldElement3.square();
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eCFieldElement2 = eCFieldElement2.square().add(square.multiply(fromBigInteger2));
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eCFieldElement3 = square.add(eCFieldElement);
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}
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if (!eCFieldElement3.isZero()) {
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return null;
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}
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} while (eCFieldElement2.square().add(eCFieldElement2).isZero());
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return eCFieldElement2;
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}
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public static byte[] encodePoint(ECPoint eCPoint) {
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ECPoint normalize = eCPoint.normalize();
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ECFieldElement affineXCoord = normalize.getAffineXCoord();
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byte[] encoded = affineXCoord.getEncoded();
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if (!affineXCoord.isZero()) {
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if (trace(normalize.getAffineYCoord().divide(affineXCoord)).isOne()) {
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int length = encoded.length - 1;
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encoded[length] = (byte) (encoded[length] | 1);
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} else {
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int length2 = encoded.length - 1;
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encoded[length2] = (byte) (encoded[length2] & 254);
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}
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}
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return encoded;
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}
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public static ECPoint decodePoint(ECCurve eCCurve, byte[] bArr) {
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ECFieldElement eCFieldElement;
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ECFieldElement fromBigInteger = eCCurve.fromBigInteger(BigInteger.valueOf(bArr[bArr.length - 1] & 1));
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ECFieldElement fromBigInteger2 = eCCurve.fromBigInteger(new BigInteger(1, bArr));
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if (!trace(fromBigInteger2).equals(eCCurve.getA())) {
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fromBigInteger2 = fromBigInteger2.addOne();
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}
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if (fromBigInteger2.isZero()) {
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eCFieldElement = eCCurve.getB().sqrt();
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} else {
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ECFieldElement solveQuadraticEquation = solveQuadraticEquation(eCCurve, fromBigInteger2.square().invert().multiply(eCCurve.getB()).add(eCCurve.getA()).add(fromBigInteger2));
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if (solveQuadraticEquation != null) {
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if (!trace(solveQuadraticEquation).equals(fromBigInteger)) {
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solveQuadraticEquation = solveQuadraticEquation.addOne();
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}
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eCFieldElement = fromBigInteger2.multiply(solveQuadraticEquation);
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} else {
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eCFieldElement = null;
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}
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}
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if (eCFieldElement != null) {
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return eCCurve.validatePoint(fromBigInteger2.toBigInteger(), eCFieldElement.toBigInteger());
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}
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throw new IllegalArgumentException("Invalid point compression");
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}
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}
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