98 lines
2.9 KiB
Java
98 lines
2.9 KiB
Java
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/*
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* Copyright (c) 2003, 2019, 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.Arrays;
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/**
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* This immutable class defines an elliptic curve (EC) prime
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* finite field.
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*
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* @see ECField
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*
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* @author Valerie Peng
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*
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* @since 1.5
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*/
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public class ECFieldFp implements ECField {
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private BigInteger p;
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/**
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* Creates an elliptic curve prime finite field
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* with the specified prime {@code p}.
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* @param p the prime.
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* @throws NullPointerException if {@code p} is null.
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* @throws IllegalArgumentException if {@code p}
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* is not positive.
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*/
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public ECFieldFp(BigInteger p) {
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if (p.signum() != 1) {
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throw new IllegalArgumentException("p is not positive");
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}
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this.p = p;
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}
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/**
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* Returns the field size in bits which is size of prime p
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* for this prime finite field.
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* @return the field size in bits.
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*/
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public int getFieldSize() {
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return p.bitLength();
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};
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/**
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* Returns the prime {@code p} of this prime finite field.
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* @return the prime.
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*/
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public BigInteger getP() {
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return p;
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}
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/**
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* Compares this prime finite field for equality with the
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* specified object.
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* @param obj the object to be compared.
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* @return true if {@code obj} is an instance
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* of ECFieldFp and the prime value match, false otherwise.
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*/
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public boolean equals(Object obj) {
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if (this == obj) return true;
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return obj instanceof ECFieldFp other
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&& p.equals(other.p);
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}
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/**
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* Returns a hash code value for this prime finite field.
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* @return a hash code value.
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*/
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public int hashCode() {
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return p.hashCode();
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}
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}
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