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 * Copyright (c) 2003, 2016, 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,
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 *
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package sun.security.provider;

import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.math.BigInteger;

import java.security.*;
import java.security.SecureRandom;
import java.security.spec.*;

import javax.crypto.spec.DHParameterSpec;

Cache for DSA and DH parameter specs. Used by the KeyPairGenerators
in the Sun, SunJCE, and SunPKCS11 provider if no parameters have been
explicitly specified by the application.
Author:
 Andreas Sterbenz
Since:
  1.5/**
 * Cache for DSA and DH parameter specs. Used by the KeyPairGenerators
 * in the Sun, SunJCE, and SunPKCS11 provider if no parameters have been
 * explicitly specified by the application.
 *
 * @author  Andreas Sterbenz
 * @since   1.5
 */
public final class ParameterCache {

    private ParameterCache() {
        // empty
    }

    // cache of DSA parameters
    private static final Map<Integer,DSAParameterSpec> dsaCache;

    // cache of DH parameters
    private static final Map<Integer,DHParameterSpec> dhCache;

    
Return cached DSA parameters for the given length combination of
prime and subprime, or null if none are available in the cache.
/**
     * Return cached DSA parameters for the given length combination of
     * prime and subprime, or null if none are available in the cache.
     */
    public static DSAParameterSpec getCachedDSAParameterSpec(int primeLen,
            int subprimeLen) {
        // ensure the sum is unique in all cases, i.e.
        // case#1: (512 <= p <= 1024) AND q=160
        // case#2: p=2048 AND q=224
        // case#3: p=2048 AND q=256
        // case#4: p=3072 AND q=256
        return dsaCache.get(Integer.valueOf(primeLen+subprimeLen));
    }

    
Return cached DH parameters for the given keylength, or null if none
are available in the cache.
/**
     * Return cached DH parameters for the given keylength, or null if none
     * are available in the cache.
     */
    public static DHParameterSpec getCachedDHParameterSpec(int keyLength) {
        return dhCache.get(Integer.valueOf(keyLength));
    }

    
Return DSA parameters for the given primeLen. Uses cache if
possible, generates new parameters and adds them to the cache
otherwise.
/**
     * Return DSA parameters for the given primeLen. Uses cache if
     * possible, generates new parameters and adds them to the cache
     * otherwise.
     */
    public static DSAParameterSpec getDSAParameterSpec(int primeLen,
            SecureRandom random)
            throws NoSuchAlgorithmException, InvalidParameterSpecException,
                   InvalidAlgorithmParameterException {
        if (primeLen <= 1024) {
            return getDSAParameterSpec(primeLen, 160, random);
        } else if (primeLen == 2048) {
            return getDSAParameterSpec(primeLen, 224, random);
        } else if (primeLen == 3072) {
            return getDSAParameterSpec(primeLen, 256, random);
        } else {
            return null;
        }
    }

    
Return DSA parameters for the given primeLen and subprimeLen.
Uses cache if possible, generates new parameters and adds them to the
cache otherwise.
/**
     * Return DSA parameters for the given primeLen and subprimeLen.
     * Uses cache if possible, generates new parameters and adds them to the
     * cache otherwise.
     */
    public static DSAParameterSpec getDSAParameterSpec(int primeLen,
            int subprimeLen, SecureRandom random)
            throws NoSuchAlgorithmException, InvalidParameterSpecException,
                   InvalidAlgorithmParameterException {
        DSAParameterSpec spec =
            getCachedDSAParameterSpec(primeLen, subprimeLen);
        if (spec != null) {
            return spec;
        }
        spec = getNewDSAParameterSpec(primeLen, subprimeLen, random);
        dsaCache.put(Integer.valueOf(primeLen + subprimeLen), spec);
        return spec;
    }

    
Return DH parameters for the given keylength. Uses cache if possible,
generates new parameters and adds them to the cache otherwise.
/**
     * Return DH parameters for the given keylength. Uses cache if possible,
     * generates new parameters and adds them to the cache otherwise.
     */
    public static DHParameterSpec getDHParameterSpec(int keyLength,
            SecureRandom random)
            throws NoSuchAlgorithmException, InvalidParameterSpecException {
        DHParameterSpec spec = getCachedDHParameterSpec(keyLength);
        if (spec != null) {
            return spec;
        }
        AlgorithmParameterGenerator gen =
                AlgorithmParameterGenerator.getInstance("DH");
        gen.init(keyLength, random);
        AlgorithmParameters params = gen.generateParameters();
        spec = params.getParameterSpec(DHParameterSpec.class);
        dhCache.put(Integer.valueOf(keyLength), spec);
        return spec;
    }

    
Return new DSA parameters for the given length combination of prime and
sub prime. Do not lookup in cache and do not cache the newly generated
parameters. This method really only exists for the legacy method
DSAKeyPairGenerator.initialize(int, boolean, SecureRandom).
/**
     * Return new DSA parameters for the given length combination of prime and
     * sub prime. Do not lookup in cache and do not cache the newly generated
     * parameters. This method really only exists for the legacy method
     * DSAKeyPairGenerator.initialize(int, boolean, SecureRandom).
     */
    public static DSAParameterSpec getNewDSAParameterSpec(int primeLen,
            int subprimeLen, SecureRandom random)
            throws NoSuchAlgorithmException, InvalidParameterSpecException,
                   InvalidAlgorithmParameterException {
        AlgorithmParameterGenerator gen =
                AlgorithmParameterGenerator.getInstance("DSA");
        // Use init(int size, SecureRandom random) for legacy DSA key sizes
        if (primeLen < 1024) {
            gen.init(primeLen, random);
        } else {
            DSAGenParameterSpec genParams =
                new DSAGenParameterSpec(primeLen, subprimeLen);
            gen.init(genParams, random);
        }
        AlgorithmParameters params = gen.generateParameters();
        DSAParameterSpec spec = params.getParameterSpec(DSAParameterSpec.class);
        return spec;
    }

    static {
        dhCache = new ConcurrentHashMap<Integer,DHParameterSpec>();
        dsaCache = new ConcurrentHashMap<Integer,DSAParameterSpec>();

        /*
         * We support precomputed parameter for legacy 512, 768 bit moduli,
         * and (L, N) combinations of (1024, 160), (2048, 224), (2048, 256),
         * (3072, 256). In this file we provide both the seed and counter
         * value of the generation process for each of these seeds,
         * for validation purposes. We also include the test vectors
         * from the DSA specification, FIPS 186, and the FIPS 186
         * Change No 1, which updates the test vector using SHA-1
         * instead of SHA (for both the G function and the message
         * hash.
         */

        /*
         * L = 512
         * SEED = b869c82b35d70e1b1ff91b28e37a62ecdc34409b
         * counter = 123
         */
        BigInteger p512 =
            new BigInteger("fca682ce8e12caba26efccf7110e526db078b05edecb" +
                           "cd1eb4a208f3ae1617ae01f35b91a47e6df63413c5e1" +
                           "2ed0899bcd132acd50d99151bdc43ee737592e17", 16);

        BigInteger q512 =
            new BigInteger("962eddcc369cba8ebb260ee6b6a126d9346e38c5", 16);

        BigInteger g512 =
            new BigInteger("678471b27a9cf44ee91a49c5147db1a9aaf244f05a43" +
                           "4d6486931d2d14271b9e35030b71fd73da179069b32e" +
                           "2935630e1c2062354d0da20a6c416e50be794ca4", 16);

        /*
         * L = 768
         * SEED = 77d0f8c4dad15eb8c4f2f8d6726cefd96d5bb399
         * counter = 263
         */
        BigInteger p768 =
            new BigInteger("e9e642599d355f37c97ffd3567120b8e25c9cd43e" +
                           "927b3a9670fbec5d890141922d2c3b3ad24800937" +
                           "99869d1e846aab49fab0ad26d2ce6a22219d470bc" +
                           "e7d777d4a21fbe9c270b57f607002f3cef8393694" +
                           "cf45ee3688c11a8c56ab127a3daf", 16);

        BigInteger q768 =
            new BigInteger("9cdbd84c9f1ac2f38d0f80f42ab952e7338bf511",
                           16);

        BigInteger g768 =
            new BigInteger("30470ad5a005fb14ce2d9dcd87e38bc7d1b1c5fac" +
                           "baecbe95f190aa7a31d23c4dbbcbe06174544401a" +
                           "5b2c020965d8c2bd2171d3668445771f74ba084d2" +
                           "029d83c1c158547f3a9f1a2715be23d51ae4d3e5a" +
                           "1f6a7064f316933a346d3f529252", 16);


        /*
         * L = 1024
         * SEED = 8d5155894229d5e689ee01e6018a237e2cae64cd
         * counter = 92
         */
        BigInteger p1024 =
            new BigInteger("fd7f53811d75122952df4a9c2eece4e7f611b7523c" +
                           "ef4400c31e3f80b6512669455d402251fb593d8d58" +
                           "fabfc5f5ba30f6cb9b556cd7813b801d346ff26660" +
                           "b76b9950a5a49f9fe8047b1022c24fbba9d7feb7c6" +
                           "1bf83b57e7c6a8a6150f04fb83f6d3c51ec3023554" +
                           "135a169132f675f3ae2b61d72aeff22203199dd148" +
                           "01c7", 16);

        BigInteger q1024 =
            new BigInteger("9760508f15230bccb292b982a2eb840bf0581cf5",
                           16);

        BigInteger g1024 =
            new BigInteger("f7e1a085d69b3ddecbbcab5c36b857b97994afbbfa" +
                           "3aea82f9574c0b3d0782675159578ebad4594fe671" +
                           "07108180b449167123e84c281613b7cf09328cc8a6" +
                           "e13c167a8b547c8d28e0a3ae1e2bb3a675916ea37f" +
                           "0bfa213562f1fb627a01243bcca4f1bea8519089a8" +
                           "83dfe15ae59f06928b665e807b552564014c3bfecf" +
                           "492a", 16);

        dsaCache.put(Integer.valueOf(512+160),
                                new DSAParameterSpec(p512, q512, g512));
        dsaCache.put(Integer.valueOf(768+160),
                                new DSAParameterSpec(p768, q768, g768));
        dsaCache.put(Integer.valueOf(1024+160),
                                new DSAParameterSpec(p1024, q1024, g1024));
        /*
         * L = 2048, N = 224
         * SEED = 584236080cfa43c09b02354135f4cc5198a19efada08bd866d601ba4
         * counter = 2666
         */
        BigInteger p2048_224 =
            new BigInteger("8f7935d9b9aae9bfabed887acf4951b6f32ec59e3b" +
                           "af3718e8eac4961f3efd3606e74351a9c4183339b8" +
                           "09e7c2ae1c539ba7475b85d011adb8b47987754984" +
                           "695cac0e8f14b3360828a22ffa27110a3d62a99345" +
                           "3409a0fe696c4658f84bdd20819c3709a01057b195" +
                           "adcd00233dba5484b6291f9d648ef883448677979c" +
                           "ec04b434a6ac2e75e9985de23db0292fc1118c9ffa" +
                           "9d8181e7338db792b730d7b9e349592f6809987215" +
                           "3915ea3d6b8b4653c633458f803b32a4c2e0f27290" +
                           "256e4e3f8a3b0838a1c450e4e18c1a29a37ddf5ea1" +
                           "43de4b66ff04903ed5cf1623e158d487c608e97f21" +
                           "1cd81dca23cb6e380765f822e342be484c05763939" +
                           "601cd667", 16);

        BigInteger q2048_224 =
            new BigInteger("baf696a68578f7dfdee7fa67c977c785ef32b233ba" +
                           "e580c0bcd5695d", 16);

        BigInteger g2048_224 =
            new BigInteger("16a65c58204850704e7502a39757040d34da3a3478" +
                           "c154d4e4a5c02d242ee04f96e61e4bd0904abdac8f" +
                           "37eeb1e09f3182d23c9043cb642f88004160edf9ca" +
                           "09b32076a79c32a627f2473e91879ba2c4e744bd20" +
                           "81544cb55b802c368d1fa83ed489e94e0fa0688e32" +
                           "428a5c78c478c68d0527b71c9a3abb0b0be12c4468" +
                           "9639e7d3ce74db101a65aa2b87f64c6826db3ec72f" +
                           "4b5599834bb4edb02f7c90e9a496d3a55d535bebfc" +
                           "45d4f619f63f3dedbb873925c2f224e07731296da8" +
                           "87ec1e4748f87efb5fdeb75484316b2232dee553dd" +
                           "af02112b0d1f02da30973224fe27aeda8b9d4b2922" +
                           "d9ba8be39ed9e103a63c52810bc688b7e2ed4316e1" +
                           "ef17dbde", 16);

        dsaCache.put(Integer.valueOf(2048+224),
                     new DSAParameterSpec(p2048_224, q2048_224, g2048_224));

        /*
         * L = 2048, N = 256
         * SEED = b0b4417601b59cbc9d8ac8f935cadaec \
         *        4f5fbb2f23785609ae466748d9b5a536
         * counter = 497
         */
        BigInteger p2048_256 =
            new BigInteger("95475cf5d93e596c3fcd1d902add02f427f5f3c721" +
                           "0313bb45fb4d5bb2e5fe1cbd678cd4bbdd84c9836b" +
                           "e1f31c0777725aeb6c2fc38b85f48076fa76bcd814" +
                           "6cc89a6fb2f706dd719898c2083dc8d896f84062e2" +
                           "c9c94d137b054a8d8096adb8d51952398eeca852a0" +
                           "af12df83e475aa65d4ec0c38a9560d5661186ff98b" +
                           "9fc9eb60eee8b030376b236bc73be3acdbd74fd61c" +
                           "1d2475fa3077b8f080467881ff7e1ca56fee066d79" +
                           "506ade51edbb5443a563927dbc4ba520086746175c" +
                           "8885925ebc64c6147906773496990cb714ec667304" +
                           "e261faee33b3cbdf008e0c3fa90650d97d3909c927" +
                           "5bf4ac86ffcb3d03e6dfc8ada5934242dd6d3bcca2" +
                           "a406cb0b", 16);

        BigInteger q2048_256 =
            new BigInteger("f8183668ba5fc5bb06b5981e6d8b795d30b8978d43" +
                           "ca0ec572e37e09939a9773", 16);

        BigInteger g2048_256 =
            new BigInteger("42debb9da5b3d88cc956e08787ec3f3a09bba5f48b" +
                           "889a74aaf53174aa0fbe7e3c5b8fcd7a53bef563b0" +
                           "e98560328960a9517f4014d3325fc7962bf1e04937" +
                           "0d76d1314a76137e792f3f0db859d095e4a5b93202" +
                           "4f079ecf2ef09c797452b0770e1350782ed57ddf79" +
                           "4979dcef23cb96f183061965c4ebc93c9c71c56b92" +
                           "5955a75f94cccf1449ac43d586d0beee43251b0b22" +
                           "87349d68de0d144403f13e802f4146d882e057af19" +
                           "b6f6275c6676c8fa0e3ca2713a3257fd1b27d0639f" +
                           "695e347d8d1cf9ac819a26ca9b04cb0eb9b7b03598" +
                           "8d15bbac65212a55239cfc7e58fae38d7250ab9991" +
                           "ffbc97134025fe8ce04c4399ad96569be91a546f49" +
                           "78693c7a", 16);

        dsaCache.put(Integer.valueOf(2048+256),
                new DSAParameterSpec(p2048_256, q2048_256, g2048_256));


        /*
         * L = 3072, N = 256
         * SEED = 9fe304be4d6b9919559f39d5911d12e9 \
         *        5158d6946598cd59775b8f3b8fff3a3f
         * counter = 1186
         */
        BigInteger p3072_256 = new BigInteger(
                "ea9cda9f5fbda66dd830494609405687ab7cf38538e058d1" +
                "e2f68dea95364866e1c05beacded24227edee28cad80bcec" +
                "ad39913be3b713267b3b96c8d9f0f6a03b5dfc9222d5cfe4" +
                "afcc9982f33784f760c3b759aebe3bbe9098a6b84c96f1fd" +
                "e44ce11c084c2a082c7a76a0ef142928b4f328406ab9beb2" +
                "4f84577dd0f46ce86fd8f08488269998bf4742d6425f7a0e" +
                "c75d8660c5dd6f4e3b3d3bee81b2c21afe8c9e8b84b87192" +
                "e2cc20f961d2bcd8133afcf3675ab80681cb374c78f33e29" +
                "d1011083d89f9c5728b94676fccb1b57bc60288c15d85ae8" +
                "38ae1941c5a20ae2b2049b3583fe30da455ddb3e6ad9b995" +
                "5cd9bb5681431622beb0f92da533fcab496cebc447aa1bb5" +
                "a8039522f2da98ff416289323a64df626ab6881870927dce" +
                "e387f13b5c9d24d6cba1d82ed375a082506ee87bc7ae3006" +
                "7f4a94e2ee363d992c40f2725b5db4b3525ebde22bbbfd0f" +
                "a124a588b0f5a4acb3a86951aff09f8c8198fb5b53da0c93" +
                "1cedc598b4f835b779d04d99026c7ba08c4b27f118ac1e3d", 16);

        BigInteger q3072_256 = new BigInteger(
                "c4eeac2bbab79bd831946d717a56a6e687547aa8e9c5494a" +
                "5a4b2f4ca13d6c11", 16);

        BigInteger g3072_256 = new BigInteger(
                "42e5fa7844f8fa9d8998d830d004e7b15b1d276bcbe5f12c" +
                "35ec90c1a25f5832018a6724bd9cdbe803b675509bed167f" +
                "3d7cf8599fc865c6d5a0f79158c1bc918f00a944d0ad0f38" +
                "f520fb91d85d82674d0d5f874faa5fcdfe56cd178c1afdc7" +
                "ce8795727b7dee966ed0b3c5cedcef8aca628befebf2d105" +
                "c7aff8eb0da9c9610737dd64dce1237b82c1b2bc8608d55f" +
                "fda98d7189444e65883315669c05716bde36c78b130aa3df" +
                "2e4d609914c7c8dc470f4e300187c775f81e7b1a9c0dce40" +
                "5d6eab2cbb9d9c4ef44412ba573dd403c4ed7bc2364772f5" +
                "6a30c48de78f5003f9371c55262d2c8ac2246ade3b02fdcf" +
                "cf5cbfde74fbcbfe6e0e0fdf3160764f84d311c179a40af6" +
                "79a8f47ab13c8f706893245eb11edcce451fa2ab98001998" +
                "7f125d8dc96622d419ba0d71f16c6024dce9d364c3b26d8e" +
                "c1a3c828f6c9d14b1d0333b95db77bfdbe3c6bce5337a1a5" +
                "a7ace10111219448447197e2a344cc423be768bb89e27be6" +
                "cbd22085614a5a3360be23b1bfbb6e6e6471363d32c85d31", 16);

        dsaCache.put(Integer.valueOf(3072+256),
                new DSAParameterSpec(p3072_256, q3072_256, g3072_256));

        //
        // Diffie-Hellman Groups
        //

        // the common generator
        BigInteger dhG = BigInteger.TWO;

        //
        // From RFC 7296

        // The prime is: 2^768 - 2 ^704 - 1 + 2^64 * { [2^638 pi] + 149686 }
        BigInteger dhP768 = new BigInteger(
                "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" +
                "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" +
                "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" +
                "E485B576625E7EC6F44C42E9A63A3620FFFFFFFFFFFFFFFF", 16);

        // The prime is 2^1024 - 2^960 - 1 + 2^64 * { [2^894 pi] + 129093 }
        BigInteger dhP1024 = new BigInteger(
                "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" +
                "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" +
                "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" +
                "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" +
                "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381" +
                "FFFFFFFFFFFFFFFF", 16);

        //
        // From RFC 3526

        // The prime is: 2^1536 - 2^1472 - 1 + 2^64 * { [2^1406 pi] + 741804 }
        BigInteger dhP1536 = new BigInteger(
                "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" +
                "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" +
                "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" +
                "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" +
                "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D" +
                "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F" +
                "83655D23DCA3AD961C62F356208552BB9ED529077096966D" +
                "670C354E4ABC9804F1746C08CA237327FFFFFFFFFFFFFFFF", 16);

        // This prime is: 2^2048 - 2^1984 - 1 + 2^64 * { [2^1918 pi] + 124476 }
        BigInteger dhP2048 = new BigInteger(
                "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" +
                "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" +
                "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" +
                "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" +
                "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D" +
                "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F" +
                "83655D23DCA3AD961C62F356208552BB9ED529077096966D" +
                "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B" +
                "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9" +
                "DE2BCBF6955817183995497CEA956AE515D2261898FA0510" +
                "15728E5A8AACAA68FFFFFFFFFFFFFFFF", 16);

        // This prime is: 2^3072 - 2^3008 - 1 + 2^64 * { [2^2942 pi] + 1690314 }
        BigInteger dhP3072 = new BigInteger(
                "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" +
                "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" +
                "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" +
                "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" +
                "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D" +
                "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F" +
                "83655D23DCA3AD961C62F356208552BB9ED529077096966D" +
                "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B" +
                "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9" +
                "DE2BCBF6955817183995497CEA956AE515D2261898FA0510" +
                "15728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64" +
                "ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7" +
                "ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6B" +
                "F12FFA06D98A0864D87602733EC86A64521F2B18177B200C" +
                "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB31" +
                "43DB5BFCE0FD108E4B82D120A93AD2CAFFFFFFFFFFFFFFFF", 16);

        // This prime is: 2^4096 - 2^4032 - 1 + 2^64 * { [2^3966 pi] + 240904 }
        BigInteger dhP4096 = new BigInteger(
                "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" +
                "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" +
                "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" +
                "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" +
                "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D" +
                "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F" +
                "83655D23DCA3AD961C62F356208552BB9ED529077096966D" +
                "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B" +
                "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9" +
                "DE2BCBF6955817183995497CEA956AE515D2261898FA0510" +
                "15728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64" +
                "ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7" +
                "ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6B" +
                "F12FFA06D98A0864D87602733EC86A64521F2B18177B200C" +
                "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB31" +
                "43DB5BFCE0FD108E4B82D120A92108011A723C12A787E6D7" +
                "88719A10BDBA5B2699C327186AF4E23C1A946834B6150BDA" +
                "2583E9CA2AD44CE8DBBBC2DB04DE8EF92E8EFC141FBECAA6" +
                "287C59474E6BC05D99B2964FA090C3A2233BA186515BE7ED" +
                "1F612970CEE2D7AFB81BDD762170481CD0069127D5B05AA9" +
                "93B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934063199" +
                "FFFFFFFFFFFFFFFF", 16);

        // This prime is: 2^6144 - 2^6080 - 1 + 2^64 * { [2^6014 pi] + 929484 }
        BigInteger dhP6144 = new BigInteger(
                "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08" +
                "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B" +
                "302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9" +
                "A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6" +
                "49286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8" +
                "FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D" +
                "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C" +
                "180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF695581718" +
                "3995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D" +
                "04507A33A85521ABDF1CBA64ECFB850458DBEF0A8AEA71575D060C7D" +
                "B3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D226" +
                "1AD2EE6BF12FFA06D98A0864D87602733EC86A64521F2B18177B200C" +
                "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFC" +
                "E0FD108E4B82D120A92108011A723C12A787E6D788719A10BDBA5B26" +
                "99C327186AF4E23C1A946834B6150BDA2583E9CA2AD44CE8DBBBC2DB" +
                "04DE8EF92E8EFC141FBECAA6287C59474E6BC05D99B2964FA090C3A2" +
                "233BA186515BE7ED1F612970CEE2D7AFB81BDD762170481CD0069127" +
                "D5B05AA993B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934028492" +
                "36C3FAB4D27C7026C1D4DCB2602646DEC9751E763DBA37BDF8FF9406" +
                "AD9E530EE5DB382F413001AEB06A53ED9027D831179727B0865A8918" +
                "DA3EDBEBCF9B14ED44CE6CBACED4BB1BDB7F1447E6CC254B33205151" +
                "2BD7AF426FB8F401378CD2BF5983CA01C64B92ECF032EA15D1721D03" +
                "F482D7CE6E74FEF6D55E702F46980C82B5A84031900B1C9E59E7C97F" +
                "BEC7E8F323A97A7E36CC88BE0F1D45B7FF585AC54BD407B22B4154AA" +
                "CC8F6D7EBF48E1D814CC5ED20F8037E0A79715EEF29BE32806A1D58B" +
                "B7C5DA76F550AA3D8A1FBFF0EB19CCB1A313D55CDA56C9EC2EF29632" +
                "387FE8D76E3C0468043E8F663F4860EE12BF2D5B0B7474D6E694F91E" +
                "6DCC4024FFFFFFFFFFFFFFFF", 16);

        // This prime is: 2^8192 - 2^8128 - 1 + 2^64 * { [2^8062 pi] + 4743158 }
        BigInteger dhP8192 = new BigInteger(
                "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1" +
                "29024E088A67CC74020BBEA63B139B22514A08798E3404DD" +
                "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245" +
                "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" +
                "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D" +
                "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F" +
                "83655D23DCA3AD961C62F356208552BB9ED529077096966D" +
                "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B" +
                "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9" +
                "DE2BCBF6955817183995497CEA956AE515D2261898FA0510" +
                "15728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64" +
                "ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7" +
                "ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6B" +
                "F12FFA06D98A0864D87602733EC86A64521F2B18177B200C" +
                "BBE117577A615D6C770988C0BAD946E208E24FA074E5AB31" +
                "43DB5BFCE0FD108E4B82D120A92108011A723C12A787E6D7" +
                "88719A10BDBA5B2699C327186AF4E23C1A946834B6150BDA" +
                "2583E9CA2AD44CE8DBBBC2DB04DE8EF92E8EFC141FBECAA6" +
                "287C59474E6BC05D99B2964FA090C3A2233BA186515BE7ED" +
                "1F612970CEE2D7AFB81BDD762170481CD0069127D5B05AA9" +
                "93B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934028492" +
                "36C3FAB4D27C7026C1D4DCB2602646DEC9751E763DBA37BD" +
                "F8FF9406AD9E530EE5DB382F413001AEB06A53ED9027D831" +
                "179727B0865A8918DA3EDBEBCF9B14ED44CE6CBACED4BB1B" +
                "DB7F1447E6CC254B332051512BD7AF426FB8F401378CD2BF" +
                "5983CA01C64B92ECF032EA15D1721D03F482D7CE6E74FEF6" +
                "D55E702F46980C82B5A84031900B1C9E59E7C97FBEC7E8F3" +
                "23A97A7E36CC88BE0F1D45B7FF585AC54BD407B22B4154AA" +
                "CC8F6D7EBF48E1D814CC5ED20F8037E0A79715EEF29BE328" +
                "06A1D58BB7C5DA76F550AA3D8A1FBFF0EB19CCB1A313D55C" +
                "DA56C9EC2EF29632387FE8D76E3C0468043E8F663F4860EE" +
                "12BF2D5B0B7474D6E694F91E6DBE115974A3926F12FEE5E4" +
                "38777CB6A932DF8CD8BEC4D073B931BA3BC832B68D9DD300" +
                "741FA7BF8AFC47ED2576F6936BA424663AAB639C5AE4F568" +
                "3423B4742BF1C978238F16CBE39D652DE3FDB8BEFC848AD9" +
                "22222E04A4037C0713EB57A81A23F0C73473FC646CEA306B" +
                "4BCBC8862F8385DDFA9D4B7FA2C087E879683303ED5BDD3A" +
                "062B3CF5B3A278A66D2A13F83F44F82DDF310EE074AB6A36" +
                "4597E899A0255DC164F31CC50846851DF9AB48195DED7EA1" +
                "B1D510BD7EE74D73FAF36BC31ECFA268359046F4EB879F92" +
                "4009438B481C6CD7889A002ED5EE382BC9190DA6FC026E47" +
                "9558E4475677E9AA9E3050E2765694DFC81F56E880B96E71" +
                "60C980DD98EDD3DFFFFFFFFFFFFFFFFF", 16);

        // use DSA parameters for DH for sizes not defined in RFC 7296, 3526
        dhCache.put(Integer.valueOf(512), new DHParameterSpec(p512, g512));

        dhCache.put(Integer.valueOf(768), new DHParameterSpec(dhP768, dhG));
        dhCache.put(Integer.valueOf(1024), new DHParameterSpec(dhP1024, dhG));
        dhCache.put(Integer.valueOf(1536), new DHParameterSpec(dhP1536, dhG));
        dhCache.put(Integer.valueOf(2048), new DHParameterSpec(dhP2048, dhG));
        dhCache.put(Integer.valueOf(3072), new DHParameterSpec(dhP3072, dhG));
        dhCache.put(Integer.valueOf(4096), new DHParameterSpec(dhP4096, dhG));
        dhCache.put(Integer.valueOf(6144), new DHParameterSpec(dhP6144, dhG));
        dhCache.put(Integer.valueOf(8192), new DHParameterSpec(dhP8192, dhG));
    }
}