jdk/src/share/classes/sun/security/ec/ECDHKeyAgreement.java
changeset 3492 e549cea58864
child 3863 8e0f58b1c072
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/sun/security/ec/ECDHKeyAgreement.java	Tue Aug 11 16:52:26 2009 +0100
@@ -0,0 +1,189 @@
+/*
+ * Copyright 2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package sun.security.ec;
+
+import java.security.*;
+import java.security.interfaces.*;
+import java.security.spec.*;
+
+import javax.crypto.*;
+import javax.crypto.spec.*;
+
+/**
+ * KeyAgreement implementation for ECDH.
+ *
+ * @since   1.7
+ */
+public final class ECDHKeyAgreement extends KeyAgreementSpi {
+
+    // flag indicating whether the native ECC implementation is present
+    private static boolean implementationPresent = true;
+    static {
+        try {
+            AccessController.doPrivileged(new PrivilegedAction<Void>() {
+                public Void run() {
+                    System.loadLibrary("sunecc");
+                    return null;
+                }
+            });
+        } catch (UnsatisfiedLinkError e) {
+            implementationPresent = false;
+        }
+    }
+
+    // private key, if initialized
+    private ECPrivateKey privateKey;
+
+    // encoded public point, non-null between doPhase() & generateSecret() only
+    private byte[] publicValue;
+
+    // length of the secret to be derived
+    private int secretLen;
+
+    /**
+     * Constructs a new ECDHKeyAgreement.
+     *
+     * @exception ProviderException if the native ECC library is unavailable.
+     */
+    public ECDHKeyAgreement() {
+        if (!implementationPresent) {
+            throw new ProviderException("ECDH implementation is not available");
+        }
+    }
+
+    // see JCE spec
+    protected void engineInit(Key key, SecureRandom random)
+            throws InvalidKeyException {
+        if (!(key instanceof PrivateKey)) {
+            throw new InvalidKeyException
+                        ("Key must be instance of PrivateKey");
+        }
+        privateKey = (ECPrivateKey) ECKeyFactory.toECKey(key);
+        publicValue = null;
+    }
+
+    // see JCE spec
+    protected void engineInit(Key key, AlgorithmParameterSpec params,
+            SecureRandom random) throws InvalidKeyException,
+            InvalidAlgorithmParameterException {
+        if (params != null) {
+            throw new InvalidAlgorithmParameterException
+                        ("Parameters not supported");
+        }
+        engineInit(key, random);
+    }
+
+    // see JCE spec
+    protected Key engineDoPhase(Key key, boolean lastPhase)
+            throws InvalidKeyException, IllegalStateException {
+        if (privateKey == null) {
+            throw new IllegalStateException("Not initialized");
+        }
+        if (publicValue != null) {
+            throw new IllegalStateException("Phase already executed");
+        }
+        if (!lastPhase) {
+            throw new IllegalStateException
+                ("Only two party agreement supported, lastPhase must be true");
+        }
+        if (!(key instanceof ECPublicKey)) {
+            throw new InvalidKeyException
+                ("Key must be a PublicKey with algorithm EC");
+        }
+
+        ECPublicKey ecKey = (ECPublicKey)key;
+        ECParameterSpec params = ecKey.getParams();
+
+        if (ecKey instanceof ECPublicKeyImpl) {
+            publicValue = ((ECPublicKeyImpl)ecKey).getEncodedPublicValue();
+        } else { // instanceof ECPublicKey
+            publicValue =
+                ECParameters.encodePoint(ecKey.getW(), params.getCurve());
+        }
+        int keyLenBits = params.getCurve().getField().getFieldSize();
+        secretLen = (keyLenBits + 7) >> 3;
+
+        return null;
+    }
+
+    // see JCE spec
+    protected byte[] engineGenerateSecret() throws IllegalStateException {
+        if ((privateKey == null) || (publicValue == null)) {
+            throw new IllegalStateException("Not initialized correctly");
+        }
+
+        byte[] s = privateKey.getS().toByteArray();
+        byte[] encodedParams =
+            ECParameters.encodeParameters(privateKey.getParams()); // DER OID
+
+        try {
+
+            return deriveKey(s, publicValue, encodedParams);
+
+        } catch (GeneralSecurityException e) {
+            throw new ProviderException("Could not derive key", e);
+        }
+
+    }
+
+    // see JCE spec
+    protected int engineGenerateSecret(byte[] sharedSecret, int
+            offset) throws IllegalStateException, ShortBufferException {
+        if (offset + secretLen > sharedSecret.length) {
+            throw new ShortBufferException("Need " + secretLen
+                + " bytes, only " + (sharedSecret.length - offset) + " available");
+        }
+        byte[] secret = engineGenerateSecret();
+        System.arraycopy(secret, 0, sharedSecret, offset, secret.length);
+        return secret.length;
+    }
+
+    // see JCE spec
+    protected SecretKey engineGenerateSecret(String algorithm)
+            throws IllegalStateException, NoSuchAlgorithmException,
+            InvalidKeyException {
+        if (algorithm == null) {
+            throw new NoSuchAlgorithmException("Algorithm must not be null");
+        }
+        if (!(algorithm.equals("TlsPremasterSecret"))) {
+            throw new NoSuchAlgorithmException
+                ("Only supported for algorithm TlsPremasterSecret");
+        }
+        return new SecretKeySpec(engineGenerateSecret(), "TlsPremasterSecret");
+    }
+
+    /**
+     * Generates a secret key using the public and private keys.
+     *
+     * @param s the private key's S value.
+     * @param w the public key's W point (in uncompressed form).
+     * @param encodedParams the curve's DER encoded object identifier.
+     *
+     * @return byte[] the secret key.
+     */
+    private static native byte[] deriveKey(byte[] s, byte[] w,
+        byte[] encodedParams) throws GeneralSecurityException;
+}