1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package org.conscrypt;
18
19import java.math.BigInteger;
20import java.security.InvalidAlgorithmParameterException;
21import java.security.KeyPair;
22import java.security.KeyPairGeneratorSpi;
23import java.security.SecureRandom;
24import java.security.spec.AlgorithmParameterSpec;
25
26import javax.crypto.spec.DHParameterSpec;
27
28public class OpenSSLDHKeyPairGenerator extends KeyPairGeneratorSpi {
29
30    /** The safe prime to use for the generated DH key pair. */
31    private BigInteger prime;
32
33    /** If {@code prime} is unspecified, this is the size of the generated prime. */
34    private int primeBits = 1024;
35
36    private static final BigInteger DEFAULT_GENERATOR = BigInteger.valueOf(2);
37
38    private BigInteger generator = DEFAULT_GENERATOR;
39
40    @Override
41    public KeyPair generateKeyPair() {
42        final OpenSSLKey key;
43        if (prime != null) {
44            key = new OpenSSLKey(NativeCrypto.EVP_PKEY_new_DH(prime.toByteArray(),
45                    generator.toByteArray(), null, null));
46        } else {
47            key = new OpenSSLKey(NativeCrypto.DH_generate_parameters_ex(primeBits,
48                    generator.longValue()));
49        }
50
51        NativeCrypto.DH_generate_key(key.getPkeyContext());
52
53        final OpenSSLDHPrivateKey privKey = new OpenSSLDHPrivateKey(key);
54        final OpenSSLDHPublicKey pubKey = new OpenSSLDHPublicKey(key);
55
56        return new KeyPair(pubKey, privKey);
57    }
58
59    @Override
60    public void initialize(int keysize, SecureRandom random) {
61        prime = null;
62        primeBits = keysize;
63        generator = DEFAULT_GENERATOR;
64    }
65
66    @Override
67    public void initialize(AlgorithmParameterSpec params, SecureRandom random)
68            throws InvalidAlgorithmParameterException {
69        prime = null;
70        primeBits = 1024;
71        generator = DEFAULT_GENERATOR;
72
73        if (params instanceof DHParameterSpec) {
74            DHParameterSpec dhParams = (DHParameterSpec) params;
75
76            prime = dhParams.getP();
77            BigInteger gen = dhParams.getG();
78            if (gen != null) {
79                generator = gen;
80            }
81        } else if (params != null) {
82            throw new InvalidAlgorithmParameterException("Params must be DHParameterSpec");
83        }
84    }
85}
86