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Diffstat (limited to 'libjava/classpath/gnu/javax/crypto/key/dh/GnuDHKeyPairGenerator.java')
| -rw-r--r-- | libjava/classpath/gnu/javax/crypto/key/dh/GnuDHKeyPairGenerator.java | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/javax/crypto/key/dh/GnuDHKeyPairGenerator.java b/libjava/classpath/gnu/javax/crypto/key/dh/GnuDHKeyPairGenerator.java new file mode 100644 index 00000000000..eafc8d01c1f --- /dev/null +++ b/libjava/classpath/gnu/javax/crypto/key/dh/GnuDHKeyPairGenerator.java @@ -0,0 +1,290 @@ +/* GnuDHKeyPairGenerator.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.hash.Sha160; +import gnu.java.security.key.IKeyPairGenerator; +import gnu.java.security.util.PRNG; + +import java.io.PrintWriter; +import java.math.BigInteger; +import java.security.KeyPair; +import java.security.PrivateKey; +import java.security.PublicKey; +import java.security.SecureRandom; +import java.util.Map; + +import javax.crypto.spec.DHGenParameterSpec; +import javax.crypto.spec.DHParameterSpec; + +/** + * <p>An implementation of a Diffie-Hellman keypair generator.</p> + * + * <p>Reference:</p> + * <ol> + * <li><a href="http://www.ietf.org/rfc/rfc2631.txt">Diffie-Hellman Key + * Agreement Method</a><br> + * Eric Rescorla.</li> + * </ol> + */ +public class GnuDHKeyPairGenerator implements IKeyPairGenerator +{ + + // Debugging methods and variables + // ------------------------------------------------------------------------- + + private static final String NAME = "dh"; + + private static final boolean DEBUG = false; + + private static final int debuglevel = 5; + + private static final PrintWriter err = new PrintWriter(System.out, true); + + private static void debug(String s) + { + err.println(">>> " + NAME + ": " + s); + } + + // Constants and variables + // ------------------------------------------------------------------------- + + /** + * Property name of an optional {@link SecureRandom} instance to use. The + * default is to use a classloader singleton from {@link PRNG}. + */ + public static final String SOURCE_OF_RANDOMNESS = "gnu.crypto.dh.prng"; + + /** + * Property name of an optional {@link DHGenParameterSpec} or + * {@link DHParameterSpec} instance to use for this generator. + */ + public static final String DH_PARAMETERS = "gnu.crypto.dh.params"; + + /** Property name of the size in bits (Integer) of the public prime (p). */ + public static final String PRIME_SIZE = "gnu.crypto.dh.L"; + + /** Property name of the size in bits (Integer) of the private exponent (x). */ + public static final String EXPONENT_SIZE = "gnu.crypto.dh.m"; + + /** + * Property name of the preferred encoding format to use when externalizing + * generated instance of key-pairs from this generator. The property is taken + * to be an {@link Integer} that encapsulates an encoding format identifier. + */ + public static final String PREFERRED_ENCODING_FORMAT = "gnu.crypto.dh.encoding"; + + /** Default value for the size in bits of the public prime (p). */ + // private static final int DEFAULT_PRIME_SIZE = 1024; + public static final int DEFAULT_PRIME_SIZE = 512; + + /** Default value for the size in bits of the private exponent (x). */ + public static final int DEFAULT_EXPONENT_SIZE = 160; + + /** Default encoding format to use when none was specified. */ + private static final int DEFAULT_ENCODING_FORMAT = Registry.RAW_ENCODING_ID; + + /** The SHA instance to use. */ + private Sha160 sha = new Sha160(); + + /** The optional {@link SecureRandom} instance to use. */ + private SecureRandom rnd = null; + + /** The desired size in bits of the public prime (p). */ + private int l; + + /** The desired size in bits of the private exponent (x). */ + private int m; + + private BigInteger seed; + + private BigInteger counter; + + private BigInteger q; + + private BigInteger p; + + private BigInteger j; + + private BigInteger g; + + /** Our default source of randomness. */ + private PRNG prng = null; + + /** Preferred encoding format of generated keys. */ + private int preferredFormat; + + // Constructor(s) + // ------------------------------------------------------------------------- + + // default 0-arguments constructor + + // Class methods + // ------------------------------------------------------------------------- + + // Instance methods + // ------------------------------------------------------------------------- + + // gnu.crypto.keys.IKeyPairGenerator interface implementation --------------- + + public String name() + { + return Registry.DH_KPG; + } + + public void setup(Map attributes) + { + // do we have a SecureRandom, or should we use our own? + rnd = (SecureRandom) attributes.get(SOURCE_OF_RANDOMNESS); + + // are we given a set of Diffie-Hellman generation parameters or we shall + // use our own? + Object params = attributes.get(DH_PARAMETERS); + + // find out the desired sizes + if (params instanceof DHGenParameterSpec) + { + DHGenParameterSpec jceSpec = (DHGenParameterSpec) params; + l = jceSpec.getPrimeSize(); + m = jceSpec.getExponentSize(); + } + else if (params instanceof DHParameterSpec) + { + DHParameterSpec jceSpec = (DHParameterSpec) params; + l = jceSpec.getP().bitLength(); + m = jceSpec.getL(); + } + else + { + Integer bi = (Integer) attributes.get(PRIME_SIZE); + l = (bi == null ? DEFAULT_PRIME_SIZE : bi.intValue()); + bi = (Integer) attributes.get(EXPONENT_SIZE); + m = (bi == null ? DEFAULT_EXPONENT_SIZE : bi.intValue()); + } + + // if ((L % 256) != 0 || L < 1024) { + if ((l % 256) != 0 || l < DEFAULT_PRIME_SIZE) + { + throw new IllegalArgumentException("invalid modulus size"); + } + if ((m % 8) != 0 || m < DEFAULT_EXPONENT_SIZE) + { + throw new IllegalArgumentException("invalid exponent size"); + } + if (m > l) + { + throw new IllegalArgumentException("exponent size > modulus size"); + } + + // what is the preferred encoding format + Integer formatID = (Integer) attributes.get(PREFERRED_ENCODING_FORMAT); + preferredFormat = formatID == null ? DEFAULT_ENCODING_FORMAT + : formatID.intValue(); + } + + public KeyPair generate() + { + if (p == null) + { + BigInteger[] params = new RFC2631(m, l, rnd).generateParameters(); + seed = params[RFC2631.DH_PARAMS_SEED]; + counter = params[RFC2631.DH_PARAMS_COUNTER]; + q = params[RFC2631.DH_PARAMS_Q]; + p = params[RFC2631.DH_PARAMS_P]; + j = params[RFC2631.DH_PARAMS_J]; + g = params[RFC2631.DH_PARAMS_G]; + if (DEBUG && debuglevel > 0) + { + debug("seed: 0x" + seed.toString(16)); + debug("counter: " + counter.intValue()); + debug("q: 0x" + q.toString(16)); + debug("p: 0x" + p.toString(16)); + debug("j: 0x" + j.toString(16)); + debug("g: 0x" + g.toString(16)); + } + } + + // generate a private number x of length m such as: 1 < x < q - 1 + BigInteger q_minus_1 = q.subtract(BigInteger.ONE); + byte[] mag = new byte[(m + 7) / 8]; + BigInteger x; + while (true) + { + nextRandomBytes(mag); + x = new BigInteger(1, mag); + if (x.bitLength() == m && x.compareTo(BigInteger.ONE) > 0 + && x.compareTo(q_minus_1) < 0) + { + break; + } + } + BigInteger y = g.modPow(x, p); + + PrivateKey secK = new GnuDHPrivateKey(preferredFormat, q, p, g, x); + PublicKey pubK = new GnuDHPublicKey(preferredFormat, q, p, g, y); + + return new KeyPair(pubK, secK); + } + + // other methods ----------------------------------------------------------- + + /** + * <p>Fills the designated byte array with random data.</p> + * + * @param buffer the byte array to fill with random data. + */ + private void nextRandomBytes(byte[] buffer) + { + if (rnd != null) + { + rnd.nextBytes(buffer); + } + else + getDefaultPRNG().nextBytes(buffer); + } + + private PRNG getDefaultPRNG() + { + if (prng == null) + prng = PRNG.getInstance(); + + return prng; + } +} |
