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Diffstat (limited to 'libjava/classpath/gnu/javax/crypto/key/dh/DiffieHellmanKeyAgreement.java')
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diff --git a/libjava/classpath/gnu/javax/crypto/key/dh/DiffieHellmanKeyAgreement.java b/libjava/classpath/gnu/javax/crypto/key/dh/DiffieHellmanKeyAgreement.java new file mode 100644 index 00000000000..5b1caa7d1b5 --- /dev/null +++ b/libjava/classpath/gnu/javax/crypto/key/dh/DiffieHellmanKeyAgreement.java @@ -0,0 +1,134 @@ +/* DiffieHellmanKeyAgreement.java -- + Copyright (C) 2003, 2006 Free Software Foundation, Inc. + +This file is a part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2 of the License, or (at +your option) any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; if not, write to the Free Software +Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 +USA + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package gnu.javax.crypto.key.dh; + +import gnu.java.security.Registry; +import gnu.java.security.util.Util; + +import gnu.javax.crypto.key.BaseKeyAgreementParty; +import gnu.javax.crypto.key.KeyAgreementException; + +import java.math.BigInteger; + +import javax.crypto.interfaces.DHPrivateKey; + +/** + * <p>The basic version of the Diffie-Hellman key agreement is described in the + * Handbook of Applied Cryptography [HAC] as follows:</p> + * <ul> + * <li>An appropriate prime p and generator g of Z<sub>p</sub><sup>*</sup> + * (2 <= g <= p-2) are selected and published.</li> + * <li>A and B each send the other one message over an open channel; as a + * result, they both can then compute a shared secret key K which they can + * use to protect their future communication.</li> + * <li>A chooses a random secret x, 1 <= x <= p-2, and sends B message + * (1) which is g^x mod p.</li> + * <li>B chooses a random secret y, 1 <= y <= p-2, and sends A message + * (2) which is g^y mod p.</li> + * <li>B receives message (1) and computes the shared key as K = (g^x)^y mod + * p.</li> + * <li>A receives message (2) and computes the shared key as K = (g^y)^x mod + * p.</li> + * </ul> + * + * <p>RFC-2631 describes a <i>Static-Static Mode</i> of operations with + * Diffie-Hellman keypairs as follows:</p> + * <pre> + * "In Static-Static mode, both the sender and the recipient have a + static (and certified) key pair. Since the sender's and recipient's + keys are therefore the same for each message, ZZ will be the same for + each message. Thus, partyAInfo MUST be used (and different for each + message) in order to ensure that different messages use different + KEKs. Implementations MAY implement Static-Static mode." + * </pre> + * + * <p>Reference:</p> + * <ol> + * <li><a href="http://www.ietf.org/rfc/rfc2631.txt">Diffie-Hellman Key + * Agreement Method</a><br> + * Eric Rescorla.</li> + * <li><a href="http://www.cacr.math.uwaterloo.ca/hac">[HAC]</a>: Handbook of + * Applied Cryptography.<br> + * CRC Press, Inc. ISBN 0-8493-8523-7, 1997<br> + * Menezes, A., van Oorschot, P. and S. Vanstone.</li> + * </ol> + */ +public abstract class DiffieHellmanKeyAgreement extends BaseKeyAgreementParty +{ + + // Constants and variables + // ------------------------------------------------------------------------- + + public static final String SOURCE_OF_RANDOMNESS = "gnu.crypto.dh.ka.prng"; + + public static final String KA_DIFFIE_HELLMAN_OWNER_PRIVATE_KEY = "gnu.crypto.dh.ka.owner.private.key"; + + /** The key agreement party's private key. */ + protected DHPrivateKey ownerKey; + + /** The shared secret key. */ + protected BigInteger ZZ; + + // Constructor(s) + // ------------------------------------------------------------------------- + + protected DiffieHellmanKeyAgreement() + { + super(Registry.DH_KA); + } + + // Class methods + // ------------------------------------------------------------------------- + + // Instance methods + // ------------------------------------------------------------------------- + + // implementation of common abstract methods in BaseKeyAGreementParty ------ + + protected byte[] engineSharedSecret() throws KeyAgreementException + { + return Util.trim(ZZ); + } + + protected void engineReset() + { + ownerKey = null; + ZZ = null; + } +} |