87 lines
3.0 KiB
Java
87 lines
3.0 KiB
Java
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/*
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* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.security.spec;
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import java.math.BigInteger;
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import java.util.Objects;
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/**
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* An elliptic curve point used to specify keys as defined by
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* <a href="https://tools.ietf.org/html/rfc8032">RFC 8032: Edwards-Curve
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* Digital Signature Algorithm (EdDSA)</a>. These points are distinct from the
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* points represented by {@code ECPoint}, and they are intended for use with
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* algorithms based on RFC 8032 such as the EdDSA {@code Signature} algorithm.
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* <p>
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* An EdEC point is specified by its y-coordinate value and a boolean that
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* indicates whether the x-coordinate is odd. The y-coordinate is an
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* element of the field of integers modulo some value p that is determined by
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* the algorithm parameters. This field element is represented by a
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* {@code BigInteger}, and implementations that consume objects of this class
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* may reject integer values which are not in the range [0, p).
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*
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* @since 15
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*/
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public final class EdECPoint {
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private final boolean xOdd;
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private final BigInteger y;
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/**
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* Construct an EdECPoint.
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*
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* @param xOdd whether the x-coordinate is odd.
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* @param y the y-coordinate, represented using a {@code BigInteger}.
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*
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* @throws NullPointerException if {@code y} is null.
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*/
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public EdECPoint(boolean xOdd, BigInteger y) {
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Objects.requireNonNull(y, "y must not be null");
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this.xOdd = xOdd;
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this.y = y;
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}
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/**
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* Get whether the x-coordinate of the point is odd.
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*
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* @return a boolean indicating whether the x-coordinate is odd.
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*/
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public boolean isXOdd() {
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return xOdd;
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}
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/**
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* Get the y-coordinate of the point.
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*
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* @return the y-coordinate, represented using a {@code BigInteger}.
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*/
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public BigInteger getY() {
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return y;
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}
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}
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