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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/gnu/javax/crypto/key/srp6/SRP6User.java | |
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Diffstat (limited to 'libjava/classpath/gnu/javax/crypto/key/srp6/SRP6User.java')
-rw-r--r-- | libjava/classpath/gnu/javax/crypto/key/srp6/SRP6User.java | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/crypto/key/srp6/SRP6User.java b/libjava/classpath/gnu/javax/crypto/key/srp6/SRP6User.java new file mode 100644 index 000000000..4a1e8dda9 --- /dev/null +++ b/libjava/classpath/gnu/javax/crypto/key/srp6/SRP6User.java @@ -0,0 +1,163 @@ +/* SRP6User.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.srp6; + +import gnu.java.security.hash.IMessageDigest; +import gnu.java.security.util.Util; +import gnu.javax.crypto.key.KeyAgreementException; +import gnu.javax.crypto.key.IncomingMessage; +import gnu.javax.crypto.key.OutgoingMessage; +import gnu.javax.crypto.sasl.srp.SRP; + +import java.math.BigInteger; +import java.security.KeyPair; +import java.security.SecureRandom; +import java.util.HashMap; +import java.util.Map; + +/** + * The implementation of the User in the SRP-6 protocol. + * <p> + * Reference: + * <ol> + * <li><a href="http://srp.stanford.edu/design.html">SRP Protocol Design</a><br> + * Thomas J. Wu.</li> + * </ol> + */ +public class SRP6User + extends SRP6KeyAgreement +{ + /** The user's identity. */ + private String I; + /** The user's cleartext password. */ + private byte[] p; + /** The user's ephemeral key pair. */ + private KeyPair userKeyPair; + + // default 0-arguments constructor + + protected void engineInit(final Map attributes) throws KeyAgreementException + { + rnd = (SecureRandom) attributes.get(SOURCE_OF_RANDOMNESS); + N = (BigInteger) attributes.get(SHARED_MODULUS); + if (N == null) + throw new KeyAgreementException("missing shared modulus"); + g = (BigInteger) attributes.get(GENERATOR); + if (g == null) + throw new KeyAgreementException("missing generator"); + final String md = (String) attributes.get(HASH_FUNCTION); + if (md == null || md.trim().length() == 0) + throw new KeyAgreementException("missing hash function"); + srp = SRP.instance(md); + I = (String) attributes.get(USER_IDENTITY); + if (I == null) + throw new KeyAgreementException("missing user identity"); + p = (byte[]) attributes.get(USER_PASSWORD); + if (p == null) + throw new KeyAgreementException("missing user password"); + } + + protected OutgoingMessage engineProcessMessage(final IncomingMessage in) + throws KeyAgreementException + { + switch (step) + { + case 0: + return sendIdentity(in); + case 1: + return computeSharedSecret(in); + default: + throw new IllegalStateException("unexpected state"); + } + } + + protected void engineReset() + { + I = null; + p = null; + userKeyPair = null; + super.engineReset(); + } + + private OutgoingMessage sendIdentity(final IncomingMessage in) + throws KeyAgreementException + { + // generate an ephemeral keypair + final SRPKeyPairGenerator kpg = new SRPKeyPairGenerator(); + final Map attributes = new HashMap(); + if (rnd != null) + attributes.put(SRPKeyPairGenerator.SOURCE_OF_RANDOMNESS, rnd); + attributes.put(SRPKeyPairGenerator.SHARED_MODULUS, N); + attributes.put(SRPKeyPairGenerator.GENERATOR, g); + kpg.setup(attributes); + userKeyPair = kpg.generate(); + final OutgoingMessage result = new OutgoingMessage(); + result.writeString(I); + result.writeMPI(((SRPPublicKey) userKeyPair.getPublic()).getY()); + return result; + } + + private OutgoingMessage computeSharedSecret(final IncomingMessage in) + throws KeyAgreementException + { + final BigInteger s = in.readMPI(); + final BigInteger B = in.readMPI(); + final BigInteger A = ((SRPPublicKey) userKeyPair.getPublic()).getY(); + final BigInteger u = uValue(A, B); // u = H(A | B) + final BigInteger x; + try + { + x = new BigInteger(1, srp.computeX(Util.trim(s), I, p)); + } + catch (Exception e) + { + throw new KeyAgreementException("computeSharedSecret()", e); + } + // compute S = (B - 3g^x) ^ (a + ux) + final BigInteger a = ((SRPPrivateKey) userKeyPair.getPrivate()).getX(); + final BigInteger S = B.subtract(THREE.multiply(g.modPow(x, N))) + .modPow(a.add(u.multiply(x)), N); + final byte[] sBytes = Util.trim(S); + final IMessageDigest hash = srp.newDigest(); + hash.update(sBytes, 0, sBytes.length); + K = new BigInteger(1, hash.digest()); + complete = true; + return null; + } +} |