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Diffstat (limited to 'libjava/classpath/javax/crypto/KeyAgreement.java')
| -rw-r--r-- | libjava/classpath/javax/crypto/KeyAgreement.java | 378 |
1 files changed, 378 insertions, 0 deletions
diff --git a/libjava/classpath/javax/crypto/KeyAgreement.java b/libjava/classpath/javax/crypto/KeyAgreement.java new file mode 100644 index 000000000..fe3e226fa --- /dev/null +++ b/libjava/classpath/javax/crypto/KeyAgreement.java @@ -0,0 +1,378 @@ +/* KeyAgreement.java -- Engine for key agreement methods. + Copyright (C) 2004 Free Software Foundation, Inc. + +This file is 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, 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; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, 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 javax.crypto; + +import gnu.java.security.Engine; + +import java.lang.reflect.InvocationTargetException; +import java.security.InvalidAlgorithmParameterException; +import java.security.InvalidKeyException; +import java.security.Key; +import java.security.NoSuchAlgorithmException; +import java.security.NoSuchProviderException; +import java.security.Provider; +import java.security.SecureRandom; +import java.security.Security; +import java.security.spec.AlgorithmParameterSpec; + +/** + * Key agreement is a method in which two or more parties may agree on a + * secret key for symmetric cryptography or message authentication + * without transmitting any secrets in the clear. Key agreement + * algorithms typically use a public/private <i>key pair</i>, and the + * public key (along with some additional information) is sent across + * untrusted networks. + * + * <p>The most common form of key agreement used today is the + * <i>Diffie-Hellman key exchange algorithm</i>, described in <a + * href="http://www.rsasecurity.com/rsalabs/pkcs/pkcs-3/">PKCS #3 - + * Diffie Hellman Key Agreement Standard</a>. + * + * @author Casey Marshall (csm@gnu.org) + * @since 1.4 + * @see KeyGenerator + * @see SecretKey + */ +public class KeyAgreement +{ + + // Fields. + // ------------------------------------------------------------------------ + + private static final String SERVICE = "KeyAgreement"; + + /** The underlying key agreement implementation. */ + private KeyAgreementSpi kaSpi; + + /** The provider of this implementation. */ + private Provider provider; + + /** The name of this instance's algorithm. */ + private String algorithm; + + /** Singnals whether or not this instance has been initialized. */ + private boolean virgin; + + // Constructor. + // ------------------------------------------------------------------------ + + protected KeyAgreement(KeyAgreementSpi kaSpi, Provider provider, + String algorithm) + { + this.kaSpi = kaSpi; + this.provider = provider; + this.algorithm = algorithm; + virgin = true; + } + + /** + * Get an implementation of an algorithm from the first provider that + * implements it. + * + * @param algorithm The name of the algorithm to get. + * @return The proper KeyAgreement instacne, if found. + * @throws NoSuchAlgorithmException If the specified algorithm is not + * implemented by any installed provider. + * @throws IllegalArgumentException if <code>algorithm</code> is + * <code>null</code> or is an empty string. + */ + public static final KeyAgreement getInstance(String algorithm) + throws NoSuchAlgorithmException + { + Provider[] p = Security.getProviders(); + NoSuchAlgorithmException lastException = null; + for (int i = 0; i < p.length; i++) + try + { + return getInstance(algorithm, p[i]); + } + catch (NoSuchAlgorithmException x) + { + lastException = x; + } + if (lastException != null) + throw lastException; + throw new NoSuchAlgorithmException(algorithm); + } + + /** + * Return an implementation of an algorithm from a named provider. + * + * @param algorithm The name of the algorithm to create. + * @param provider The name of the provider from which to get the + * implementation. + * @return The proper KeyAgreement instance, if found. + * @throws NoSuchAlgorithmException If the named provider does not implement + * the algorithm. + * @throws NoSuchProviderException If the named provider does not exist. + * @throws IllegalArgumentException if either <code>algorithm</code> or + * <code>provider</code> is <code>null</code>, or if + * <code>algorithm</code> is an empty string. + */ + public static final KeyAgreement getInstance(String algorithm, String provider) + throws NoSuchAlgorithmException, NoSuchProviderException + { + if (provider == null) + throw new IllegalArgumentException("provider MUST NOT be null"); + Provider p = Security.getProvider(provider); + if (p == null) + throw new NoSuchProviderException(provider); + return getInstance(algorithm, p); + } + + /** + * Return an implementation of an algorithm from a specific provider. + * + * @param algorithm The name of the algorithm to get. + * @param provider The provider from which to get the implementation. + * @return The proper KeyAgreement instance, if found. + * @throws NoSuchAlgorithmException If this provider does not implement the + * algorithm. + * @throws IllegalArgumentException if either <code>algorithm</code> or + * <code>provider</code> is <code>null</code>, or if + * <code>algorithm</code> is an empty string. + */ + public static final KeyAgreement getInstance(String algorithm, + Provider provider) + throws NoSuchAlgorithmException + { + StringBuilder sb = new StringBuilder("KeyAgreement algorithm [") + .append(algorithm).append("] from provider[") + .append(provider).append("] could not be created"); + Throwable cause; + try + { + Object spi = Engine.getInstance(SERVICE, algorithm, provider); + return new KeyAgreement((KeyAgreementSpi) spi, provider, algorithm); + } + catch (InvocationTargetException x) + { + cause = x.getCause(); + if (cause instanceof NoSuchAlgorithmException) + throw (NoSuchAlgorithmException) cause; + if (cause == null) + cause = x; + } + catch (ClassCastException x) + { + cause = x; + } + NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString()); + x.initCause(cause); + throw x; + } + + /** + * Do a phase in the key agreement. The number of times this method is + * called depends upon the algorithm and the number of parties + * involved, but must be called at least once with the + * <code>lastPhase</code> flag set to <code>true</code>. + * + * @param key The key for this phase. + * @param lastPhase Should be <code>true</code> if this will be the + * last phase before generating the shared secret. + * @return The intermediate result, or <code>null</code> if there is + * no intermediate result. + * @throws java.lang.IllegalStateException If this instance has not + * been initialized. + * @throws java.security.InvalidKeyException If the key is + * inappropriate for this algorithm. + */ + public final Key doPhase(Key key, boolean lastPhase) + throws IllegalStateException, InvalidKeyException + { + if (virgin) + { + throw new IllegalStateException("not initialized"); + } + return kaSpi.engineDoPhase(key, lastPhase); + } + + /** + * Generate the shared secret in a new byte array. + * + * @return The shared secret. + * @throws java.lang.IllegalStateException If this instnace has not + * been initialized, or if not enough calls to + * <code>doPhase</code> have been made. + */ + public final byte[] generateSecret() throws IllegalStateException + { + if (virgin) + { + throw new IllegalStateException("not initialized"); + } + return kaSpi.engineGenerateSecret(); + } + + /** + * Generate the shared secret and store it into the supplied array. + * + * @param sharedSecret The array in which to store the secret. + * @param offset The index in <code>sharedSecret</code> to start + * storing data. + * @return The length of the shared secret, in bytes. + * @throws java.lang.IllegalStateException If this instnace has not + * been initialized, or if not enough calls to + * <code>doPhase</code> have been made. + * @throws javax.crypto.ShortBufferException If the supplied array is + * not large enough to store the result. + */ + public final int generateSecret(byte[] sharedSecret, int offset) + throws IllegalStateException, ShortBufferException + { + if (virgin) + { + throw new IllegalStateException("not initialized"); + } + return kaSpi.engineGenerateSecret(sharedSecret, offset); + } + + /** + * Generate the shared secret and return it as an appropriate {@link + * SecretKey}. + * + * @param algorithm The secret key's algorithm. + * @return The shared secret as a secret key. + * @throws java.lang.IllegalStateException If this instnace has not + * been initialized, or if not enough calls to + * <code>doPhase</code> have been made. + * @throws java.security.InvalidKeyException If the shared secret + * cannot be used to make a {@link SecretKey}. + * @throws java.security.NoSuchAlgorithmException If the specified + * algorithm does not exist. + */ + public final SecretKey generateSecret(String algorithm) + throws IllegalStateException, InvalidKeyException, NoSuchAlgorithmException + { + if (virgin) + { + throw new IllegalStateException("not initialized"); + } + return kaSpi.engineGenerateSecret(algorithm); + } + + /** + * Return the name of this key-agreement algorithm. + * + * @return The algorithm name. + */ + public final String getAlgorithm() + { + return algorithm; + } + + /** + * Return the provider of the underlying implementation. + * + * @return The provider. + */ + public final Provider getProvider() + { + return provider; + } + + /** + * Initialize this key agreement with a key. This method will use the + * highest-priority {@link java.security.SecureRandom} as its source + * of randomness. + * + * @param key The key, usually the user's private key. + * @throws java.security.InvalidKeyException If the supplied key is + * not appropriate. + */ + public final void init(Key key) throws InvalidKeyException + { + init(key, new SecureRandom()); + } + + /** + * Initialize this key agreement with a key and a source of + * randomness. + * + * @param key The key, usually the user's private key. + * @param random The source of randomness. + * @throws java.security.InvalidKeyException If the supplied key is + * not appropriate. + */ + public final void init(Key key, SecureRandom random) + throws InvalidKeyException + { + kaSpi.engineInit(key, random); + virgin = false; // w00t! + } + + /** + * Initialize this key agreement with a key and parameters. This + * method will use the highest-priority {@link + * java.security.SecureRandom} as its source of randomness. + * + * @param key The key, usually the user's private key. + * @param params The algorithm parameters. + * @throws java.security.InvalidAlgorithmParameterException If the + * supplied parameters are not appropriate. + * @throws java.security.InvalidKeyException If the supplied key is + * not appropriate. + */ + public final void init(Key key, AlgorithmParameterSpec params) + throws InvalidAlgorithmParameterException, InvalidKeyException + { + init(key, params, new SecureRandom()); + } + + /** + * Initialize this key agreement with a key, parameters, and source of + * randomness. + * + * @param key The key, usually the user's private key. + * @param params The algorithm parameters. + * @param random The source of randomness. + * @throws java.security.InvalidAlgorithmParameterException If the + * supplied parameters are not appropriate. + * @throws java.security.InvalidKeyException If the supplied key is + * not appropriate. + */ + public final void init(Key key, AlgorithmParameterSpec params, + SecureRandom random) + throws InvalidAlgorithmParameterException, InvalidKeyException + { + kaSpi.engineInit(key, params, random); + virgin = false; // w00t! + } +} |