| /* |
| * Copyright (c) 1997, 2012, Oracle and/or its affiliates. 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. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.sun.crypto.provider; |
| |
| import java.util.*; |
| import java.lang.*; |
| import java.math.BigInteger; |
| import java.security.InvalidAlgorithmParameterException; |
| import java.security.InvalidKeyException; |
| import java.security.Key; |
| import java.security.NoSuchAlgorithmException; |
| import java.security.SecureRandom; |
| import java.security.ProviderException; |
| import java.security.spec.AlgorithmParameterSpec; |
| import java.security.spec.InvalidKeySpecException; |
| import javax.crypto.KeyAgreementSpi; |
| import javax.crypto.ShortBufferException; |
| import javax.crypto.SecretKey; |
| import javax.crypto.spec.*; |
| |
| import sun.security.util.KeyUtil; |
| |
| /** |
| * This class implements the Diffie-Hellman key agreement protocol between |
| * any number of parties. |
| * |
| * @author Jan Luehe |
| * |
| */ |
| |
| public final class DHKeyAgreement |
| extends KeyAgreementSpi { |
| |
| private boolean generateSecret = false; |
| private BigInteger init_p = null; |
| private BigInteger init_g = null; |
| private BigInteger x = BigInteger.ZERO; // the private value |
| private BigInteger y = BigInteger.ZERO; |
| |
| /** |
| * Empty constructor |
| */ |
| public DHKeyAgreement() { |
| } |
| |
| /** |
| * Initializes this key agreement with the given key and source of |
| * randomness. The given key is required to contain all the algorithm |
| * parameters required for this key agreement. |
| * |
| * <p> If the key agreement algorithm requires random bytes, it gets them |
| * from the given source of randomness, <code>random</code>. |
| * However, if the underlying |
| * algorithm implementation does not require any random bytes, |
| * <code>random</code> is ignored. |
| * |
| * @param key the party's private information. For example, in the case |
| * of the Diffie-Hellman key agreement, this would be the party's own |
| * Diffie-Hellman private key. |
| * @param random the source of randomness |
| * |
| * @exception InvalidKeyException if the given key is |
| * inappropriate for this key agreement, e.g., is of the wrong type or |
| * has an incompatible algorithm type. |
| */ |
| protected void engineInit(Key key, SecureRandom random) |
| throws InvalidKeyException |
| { |
| try { |
| engineInit(key, null, random); |
| } catch (InvalidAlgorithmParameterException e) { |
| // never happens, because we did not pass any parameters |
| } |
| } |
| |
| /** |
| * Initializes this key agreement with the given key, set of |
| * algorithm parameters, and source of randomness. |
| * |
| * @param key the party's private information. For example, in the case |
| * of the Diffie-Hellman key agreement, this would be the party's own |
| * Diffie-Hellman private key. |
| * @param params the key agreement parameters |
| * @param random the source of randomness |
| * |
| * @exception InvalidKeyException if the given key is |
| * inappropriate for this key agreement, e.g., is of the wrong type or |
| * has an incompatible algorithm type. |
| * @exception InvalidAlgorithmParameterException if the given parameters |
| * are inappropriate for this key agreement. |
| */ |
| protected void engineInit(Key key, AlgorithmParameterSpec params, |
| SecureRandom random) |
| throws InvalidKeyException, InvalidAlgorithmParameterException |
| { |
| // ignore "random" parameter, because our implementation does not |
| // require any source of randomness |
| generateSecret = false; |
| init_p = null; |
| init_g = null; |
| |
| if ((params != null) && !(params instanceof DHParameterSpec)) { |
| throw new InvalidAlgorithmParameterException |
| ("Diffie-Hellman parameters expected"); |
| } |
| if (!(key instanceof javax.crypto.interfaces.DHPrivateKey)) { |
| throw new InvalidKeyException("Diffie-Hellman private key " |
| + "expected"); |
| } |
| javax.crypto.interfaces.DHPrivateKey dhPrivKey; |
| dhPrivKey = (javax.crypto.interfaces.DHPrivateKey)key; |
| |
| // check if private key parameters are compatible with |
| // initialized ones |
| if (params != null) { |
| init_p = ((DHParameterSpec)params).getP(); |
| init_g = ((DHParameterSpec)params).getG(); |
| } |
| BigInteger priv_p = dhPrivKey.getParams().getP(); |
| BigInteger priv_g = dhPrivKey.getParams().getG(); |
| if (init_p != null && priv_p != null && !(init_p.equals(priv_p))) { |
| throw new InvalidKeyException("Incompatible parameters"); |
| } |
| if (init_g != null && priv_g != null && !(init_g.equals(priv_g))) { |
| throw new InvalidKeyException("Incompatible parameters"); |
| } |
| if ((init_p == null && priv_p == null) |
| || (init_g == null && priv_g == null)) { |
| throw new InvalidKeyException("Missing parameters"); |
| } |
| init_p = priv_p; |
| init_g = priv_g; |
| |
| // store the x value |
| this.x = dhPrivKey.getX(); |
| } |
| |
| /** |
| * Executes the next phase of this key agreement with the given |
| * key that was received from one of the other parties involved in this key |
| * agreement. |
| * |
| * @param key the key for this phase. For example, in the case of |
| * Diffie-Hellman between 2 parties, this would be the other party's |
| * Diffie-Hellman public key. |
| * @param lastPhase flag which indicates whether or not this is the last |
| * phase of this key agreement. |
| * |
| * @return the (intermediate) key resulting from this phase, or null if |
| * this phase does not yield a key |
| * |
| * @exception InvalidKeyException if the given key is inappropriate for |
| * this phase. |
| * @exception IllegalStateException if this key agreement has not been |
| * initialized. |
| */ |
| protected Key engineDoPhase(Key key, boolean lastPhase) |
| throws InvalidKeyException, IllegalStateException |
| { |
| if (!(key instanceof javax.crypto.interfaces.DHPublicKey)) { |
| throw new InvalidKeyException("Diffie-Hellman public key " |
| + "expected"); |
| } |
| javax.crypto.interfaces.DHPublicKey dhPubKey; |
| dhPubKey = (javax.crypto.interfaces.DHPublicKey)key; |
| |
| if (init_p == null || init_g == null) { |
| throw new IllegalStateException("Not initialized"); |
| } |
| |
| // check if public key parameters are compatible with |
| // initialized ones |
| BigInteger pub_p = dhPubKey.getParams().getP(); |
| BigInteger pub_g = dhPubKey.getParams().getG(); |
| if (pub_p != null && !(init_p.equals(pub_p))) { |
| throw new InvalidKeyException("Incompatible parameters"); |
| } |
| if (pub_g != null && !(init_g.equals(pub_g))) { |
| throw new InvalidKeyException("Incompatible parameters"); |
| } |
| |
| // validate the Diffie-Hellman public key |
| KeyUtil.validate(dhPubKey); |
| |
| // store the y value |
| this.y = dhPubKey.getY(); |
| |
| // we've received a public key (from one of the other parties), |
| // so we are ready to create the secret, which may be an |
| // intermediate secret, in which case we wrap it into a |
| // Diffie-Hellman public key object and return it. |
| generateSecret = true; |
| if (lastPhase == false) { |
| byte[] intermediate = engineGenerateSecret(); |
| return new DHPublicKey(new BigInteger(1, intermediate), |
| init_p, init_g); |
| } else { |
| return null; |
| } |
| } |
| |
| /** |
| * Generates the shared secret and returns it in a new buffer. |
| * |
| * <p>This method resets this <code>KeyAgreementSpi</code> object, |
| * so that it |
| * can be reused for further key agreements. Unless this key agreement is |
| * reinitialized with one of the <code>engineInit</code> methods, the same |
| * private information and algorithm parameters will be used for |
| * subsequent key agreements. |
| * |
| * @return the new buffer with the shared secret |
| * |
| * @exception IllegalStateException if this key agreement has not been |
| * completed yet |
| */ |
| protected byte[] engineGenerateSecret() |
| throws IllegalStateException |
| { |
| int expectedLen = (init_p.bitLength() + 7) >>> 3; |
| byte[] result = new byte[expectedLen]; |
| try { |
| engineGenerateSecret(result, 0); |
| } catch (ShortBufferException sbe) { |
| // should never happen since secret lengths in the two |
| // methods are identical |
| } |
| return result; |
| } |
| |
| /** |
| * Generates the shared secret, and places it into the buffer |
| * <code>sharedSecret</code>, beginning at <code>offset</code>. |
| * |
| * <p>If the <code>sharedSecret</code> buffer is too small to hold the |
| * result, a <code>ShortBufferException</code> is thrown. |
| * In this case, this call should be repeated with a larger output buffer. |
| * |
| * <p>This method resets this <code>KeyAgreementSpi</code> object, |
| * so that it |
| * can be reused for further key agreements. Unless this key agreement is |
| * reinitialized with one of the <code>engineInit</code> methods, the same |
| * private information and algorithm parameters will be used for |
| * subsequent key agreements. |
| * |
| * @param sharedSecret the buffer for the shared secret |
| * @param offset the offset in <code>sharedSecret</code> where the |
| * shared secret will be stored |
| * |
| * @return the number of bytes placed into <code>sharedSecret</code> |
| * |
| * @exception IllegalStateException if this key agreement has not been |
| * completed yet |
| * @exception ShortBufferException if the given output buffer is too small |
| * to hold the secret |
| */ |
| protected int engineGenerateSecret(byte[] sharedSecret, int offset) |
| throws IllegalStateException, ShortBufferException |
| { |
| if (generateSecret == false) { |
| throw new IllegalStateException |
| ("Key agreement has not been completed yet"); |
| } |
| |
| if (sharedSecret == null) { |
| throw new ShortBufferException |
| ("No buffer provided for shared secret"); |
| } |
| |
| BigInteger modulus = init_p; |
| int expectedLen = (modulus.bitLength() + 7) >>> 3; |
| if ((sharedSecret.length - offset) < expectedLen) { |
| throw new ShortBufferException |
| ("Buffer too short for shared secret"); |
| } |
| |
| // Reset the key agreement after checking for ShortBufferException |
| // above, so user can recover w/o losing internal state |
| generateSecret = false; |
| |
| /* |
| * NOTE: BigInteger.toByteArray() returns a byte array containing |
| * the two's-complement representation of this BigInteger with |
| * the most significant byte is in the zeroth element. This |
| * contains the minimum number of bytes required to represent |
| * this BigInteger, including at least one sign bit whose value |
| * is always 0. |
| * |
| * Keys are always positive, and the above sign bit isn't |
| * actually used when representing keys. (i.e. key = new |
| * BigInteger(1, byteArray)) To obtain an array containing |
| * exactly expectedLen bytes of magnitude, we strip any extra |
| * leading 0's, or pad with 0's in case of a "short" secret. |
| */ |
| byte[] secret = this.y.modPow(this.x, modulus).toByteArray(); |
| if (secret.length == expectedLen) { |
| System.arraycopy(secret, 0, sharedSecret, offset, |
| secret.length); |
| } else { |
| // Array too short, pad it w/ leading 0s |
| if (secret.length < expectedLen) { |
| System.arraycopy(secret, 0, sharedSecret, |
| offset + (expectedLen - secret.length), |
| secret.length); |
| } else { |
| // Array too long, check and trim off the excess |
| if ((secret.length == (expectedLen+1)) && secret[0] == 0) { |
| // ignore the leading sign byte |
| System.arraycopy(secret, 1, sharedSecret, offset, expectedLen); |
| } else { |
| throw new ProviderException("Generated secret is out-of-range"); |
| } |
| } |
| } |
| return expectedLen; |
| } |
| |
| /** |
| * Creates the shared secret and returns it as a secret key object |
| * of the requested algorithm type. |
| * |
| * <p>This method resets this <code>KeyAgreementSpi</code> object, |
| * so that it |
| * can be reused for further key agreements. Unless this key agreement is |
| * reinitialized with one of the <code>engineInit</code> methods, the same |
| * private information and algorithm parameters will be used for |
| * subsequent key agreements. |
| * |
| * @param algorithm the requested secret key algorithm |
| * |
| * @return the shared secret key |
| * |
| * @exception IllegalStateException if this key agreement has not been |
| * completed yet |
| * @exception NoSuchAlgorithmException if the requested secret key |
| * algorithm is not available |
| * @exception InvalidKeyException if the shared secret key material cannot |
| * be used to generate a secret key of the requested algorithm type (e.g., |
| * the key material is too short) |
| */ |
| protected SecretKey engineGenerateSecret(String algorithm) |
| throws IllegalStateException, NoSuchAlgorithmException, |
| InvalidKeyException |
| { |
| if (algorithm == null) { |
| throw new NoSuchAlgorithmException("null algorithm"); |
| } |
| byte[] secret = engineGenerateSecret(); |
| if (algorithm.equalsIgnoreCase("DES")) { |
| // DES |
| return new DESKey(secret); |
| } else if (algorithm.equalsIgnoreCase("DESede") |
| || algorithm.equalsIgnoreCase("TripleDES")) { |
| // Triple DES |
| return new DESedeKey(secret); |
| } else if (algorithm.equalsIgnoreCase("Blowfish")) { |
| // Blowfish |
| int keysize = secret.length; |
| if (keysize >= BlowfishConstants.BLOWFISH_MAX_KEYSIZE) |
| keysize = BlowfishConstants.BLOWFISH_MAX_KEYSIZE; |
| SecretKeySpec skey = new SecretKeySpec(secret, 0, keysize, |
| "Blowfish"); |
| return skey; |
| } else if (algorithm.equalsIgnoreCase("AES")) { |
| // AES |
| int keysize = secret.length; |
| SecretKeySpec skey = null; |
| int idx = AESConstants.AES_KEYSIZES.length - 1; |
| while (skey == null && idx >= 0) { |
| // Generate the strongest key using the shared secret |
| // assuming the key sizes in AESConstants class are |
| // in ascending order |
| if (keysize >= AESConstants.AES_KEYSIZES[idx]) { |
| keysize = AESConstants.AES_KEYSIZES[idx]; |
| skey = new SecretKeySpec(secret, 0, keysize, "AES"); |
| } |
| idx--; |
| } |
| if (skey == null) { |
| throw new InvalidKeyException("Key material is too short"); |
| } |
| return skey; |
| } else if (algorithm.equals("TlsPremasterSecret")) { |
| // return entire secret |
| return new SecretKeySpec(secret, "TlsPremasterSecret"); |
| } else { |
| throw new NoSuchAlgorithmException("Unsupported secret key " |
| + "algorithm: "+ algorithm); |
| } |
| } |
| } |