1 /* 2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package java.security.interfaces; 26 27 import java.math.BigInteger; 28 import java.security.PublicKey; 29 30 /** 31 * An interface for an elliptic curve public key as defined by RFC 7748. 32 * These keys are distinct from the keys represented by {@code ECPublicKey}, 33 * and they are intended for use with algorithms based on RFC 7748 such as the 34 * XDH {@code KeyAgreement} algorithm. 35 * 36 * An XEC public key is a particular point on the curve, which is represented 37 * using only its u-coordinate as described in RFC 7748. A u-coordinate is an 38 * element of the field of integers modulo some value that is determined by 39 * the algorithm parameters. This field element is represented by a BigInteger 40 * which may hold any value. That is, the BigInteger is not restricted to the 41 * range of canonical field elements. 42 * 43 * @since 11 44 */ 45 public interface XECPublicKey extends XECKey, PublicKey { 46 47 /** 48 * Get the u coordinate of the point. 49 * 50 * @return the u-coordinate, represented using a BigInteger which may hold 51 * any value 52 */ getU()53 BigInteger getU(); 54 55 } 56 57