1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

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);
    }
}