/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
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*
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package java.security.spec;
import java.math.BigInteger;
import java.util.Arrays;
/**
* This immutable class defines an elliptic curve (EC) prime
* finite field.
*
* @see ECField
*
* @author Valerie Peng
*
* @since 1.5
*/
public class ECFieldFp implements ECField {
private BigInteger p;
/**
* Creates an elliptic curve prime finite field
* with the specified prime <code>p</code>.
* @param p the prime.
* @exception NullPointerException if <code>p</code> is null.
* @exception IllegalArgumentException if <code>p</code>
* is not positive.
*/
public ECFieldFp(BigInteger p) {
if (p.signum() != 1) {
throw new IllegalArgumentException("p is not positive");
}
this.p = p;
}
/**
* Returns the field size in bits which is size of prime p
* for this prime finite field.
* @return the field size in bits.
*/
public int getFieldSize() {
return p.bitLength();
};
/**
* Returns the prime <code>p</code> of this prime finite field.
* @return the prime.
*/
public BigInteger getP() {
return p;
}
/**
* Compares this prime finite field for equality with the
* specified object.
* @param obj the object to be compared.
* @return true if <code>obj</code> is an instance
* of ECFieldFp and the prime value match, false otherwise.
*/
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj instanceof ECFieldFp) {
return (p.equals(((ECFieldFp)obj).p));
}
return false;
}
/**
* Returns a hash code value for this prime finite field.
* @return a hash code value.
*/
public int hashCode() {
return p.hashCode();
}
}