ru.jts_dev.authserver.config.KeyGenerationConfig.java Source code

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Here is the source code for ru.jts_dev.authserver.config.KeyGenerationConfig.java

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/*
 * Copyright (c) 2015, 2016, 2017 JTS-Team authors and/or its affiliates. All rights reserved.
 *
 * This file is part of JTS-V3 Project.
 *
 * JTS-V3 Project 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 3 of the License, or
 * (at your option) any later version.
 *
 * JTS-V3 Project 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 JTS-V3 Project.  If not, see <http://www.gnu.org/licenses/>.
 */

package ru.jts_dev.authserver.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.math.BigInteger;
import java.security.InvalidAlgorithmParameterException;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.spec.RSAKeyGenParameterSpec;

/**
 * @author Camelion
 * @since 30.11.15
 */
@Configuration
public class KeyGenerationConfig {
    static byte[] scrambleModulus(BigInteger modulus) {
        byte[] scrambledMod = modulus.toByteArray();

        if (scrambledMod.length == 0x81 && scrambledMod[0] == 0x00) {
            byte[] temp = new byte[0x80];
            System.arraycopy(scrambledMod, 1, temp, 0, 0x80);
            scrambledMod = temp;
        }
        // step 1 : 0x4d-0x50 <-> 0x00-0x04
        for (int i = 0; i < 4; i++) {
            byte temp = scrambledMod[i];
            scrambledMod[i] = scrambledMod[0x4d + i];
            scrambledMod[0x4d + i] = temp;
        }
        // step 2 : xor first 0x40 bytes with  last 0x40 bytes
        for (int i = 0; i < 0x40; i++) {
            scrambledMod[i] ^= scrambledMod[0x40 + i];
        }
        // step 3 : xor bytes 0x0d-0x10 with bytes 0x34-0x38
        for (int i = 0; i < 4; i++) {
            scrambledMod[0x0d + i] ^= scrambledMod[0x34 + i];
        }
        // step 4 : xor last 0x40 bytes with  first 0x40 bytes
        for (int i = 0; i < 0x40; i++) {
            scrambledMod[0x40 + i] ^= scrambledMod[i];
        }

        return scrambledMod;
    }

    @Bean
    public KeyPairGenerator RSAKeyPairGenerator()
            throws NoSuchAlgorithmException, InvalidAlgorithmParameterException {
        KeyPairGenerator keygen;

        keygen = KeyPairGenerator.getInstance("RSA");
        RSAKeyGenParameterSpec spec = new RSAKeyGenParameterSpec(1024, RSAKeyGenParameterSpec.F4);
        keygen.initialize(spec);

        return keygen;
    }
}