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Forked from destan/ParseRSAKeys.java
Created May 6, 2022 08:22
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Parse RSA public and private key pair from string in Java
#!/usr/bin/env bash
openssl genrsa -out private_key.pem 4096
openssl rsa -pubout -in private_key.pem -out public_key.pem
# convert private key to pkcs8 format in order to import it from Java
openssl pkcs8 -topk8 -in private_key.pem -inform pem -out private_key_pkcs8.pem -outform pem -nocrypt
import java.io.IOException;
import java.net.URISyntaxException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
/**
* This file is intended to be used on a IDE for testing purposes.
* ClassLoader.getSystemResource won't work in a JAR
*/
public class Main {
public static void main(String[] args) throws InvalidKeySpecException, NoSuchAlgorithmException, IOException, URISyntaxException {
String privateKeyContent = new String(Files.readAllBytes(Paths.get(ClassLoader.getSystemResource("private_key_pkcs8.pem").toURI())));
String publicKeyContent = new String(Files.readAllBytes(Paths.get(ClassLoader.getSystemResource("public_key.pem").toURI())));
privateKeyContent = privateKeyContent.replaceAll("\\n", "").replace("-----BEGIN PRIVATE KEY-----", "").replace("-----END PRIVATE KEY-----", "");
publicKeyContent = publicKeyContent.replaceAll("\\n", "").replace("-----BEGIN PUBLIC KEY-----", "").replace("-----END PUBLIC KEY-----", "");;
KeyFactory kf = KeyFactory.getInstance("RSA");
PKCS8EncodedKeySpec keySpecPKCS8 = new PKCS8EncodedKeySpec(Base64.getDecoder().decode(privateKeyContent));
PrivateKey privKey = kf.generatePrivate(keySpecPKCS8);
X509EncodedKeySpec keySpecX509 = new X509EncodedKeySpec(Base64.getDecoder().decode(publicKeyContent));
RSAPublicKey pubKey = (RSAPublicKey) kf.generatePublic(keySpecX509);
System.out.println(privKey);
System.out.println(pubKey);
}
}
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