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/* 
 * This file is part of cert-signer
 * Copyright (c) 2024 Paolo Lulli.
 * 
 * This program 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, version 3.
 *
 * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
 */

package net.lulli.certsigner.util;

import java.io.File;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.security.KeyFactory;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

public class Keys {
    private Keys(){}
    public static RSAPublicKey readX509PublicKey(File file) throws Exception {
        String key = new String(Files.readAllBytes(file.toPath()), Charset.defaultCharset());

        String publicKeyPEM = key
                .replace("-----BEGIN PUBLIC KEY-----", "")
                .replaceAll(System.lineSeparator(), "")
                .replace("-----END PUBLIC KEY-----", "");

        byte[] encoded = Base64.getDecoder().decode(publicKeyPEM);

        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(encoded);
        return (RSAPublicKey) keyFactory.generatePublic(keySpec);
    }
    public RSAPrivateKey readPKCS8PrivateKey(File file) throws Exception {
        String key = new String(Files.readAllBytes(file.toPath()), Charset.defaultCharset());

        String privateKeyPEM = key
                .replace("-----BEGIN PRIVATE KEY-----", "")
                .replaceAll(System.lineSeparator(), "")
                .replace("-----END PRIVATE KEY-----", "");

        byte[] encoded = Base64.getDecoder().decode(privateKeyPEM);

        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encoded);
        return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
    }
}