MainClass.java Source code

Introduction

Here is the source code for MainClass.java

Source

import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.Security;
import java.security.SignatureException;
import java.security.cert.X509Certificate;
import java.util.Date;

import javax.security.auth.x500.X500Principal;

import org.bouncycastle.asn1.x509.BasicConstraints;
import org.bouncycastle.asn1.x509.ExtendedKeyUsage;
import org.bouncycastle.asn1.x509.GeneralName;
import org.bouncycastle.asn1.x509.GeneralNames;
import org.bouncycastle.asn1.x509.KeyPurposeId;
import org.bouncycastle.asn1.x509.KeyUsage;
import org.bouncycastle.asn1.x509.X509Extensions;
import org.bouncycastle.x509.X509V3CertificateGenerator;

public class MainClass {
    public static X509Certificate generateV3Certificate(KeyPair pair)
            throws InvalidKeyException, NoSuchProviderException, SignatureException {
        Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

        X509V3CertificateGenerator certGen = new X509V3CertificateGenerator();

        certGen.setSerialNumber(BigInteger.valueOf(System.currentTimeMillis()));
        certGen.setIssuerDN(new X500Principal("CN=Test Certificate"));
        certGen.setNotBefore(new Date(System.currentTimeMillis() - 10000));
        certGen.setNotAfter(new Date(System.currentTimeMillis() + 10000));
        certGen.setSubjectDN(new X500Principal("CN=Test Certificate"));
        certGen.setPublicKey(pair.getPublic());
        certGen.setSignatureAlgorithm("SHA256WithRSAEncryption");

        certGen.addExtension(X509Extensions.BasicConstraints, true, new BasicConstraints(false));
        certGen.addExtension(X509Extensions.KeyUsage, true,
                new KeyUsage(KeyUsage.digitalSignature | KeyUsage.keyEncipherment));
        certGen.addExtension(X509Extensions.ExtendedKeyUsage, true,
                new ExtendedKeyUsage(KeyPurposeId.id_kp_serverAuth));

        certGen.addExtension(X509Extensions.SubjectAlternativeName, false,
                new GeneralNames(new GeneralName(GeneralName.rfc822Name, "test@test.test")));

        return certGen.generateX509Certificate(pair.getPrivate(), "BC");
    }

    public static void main(String[] args) throws Exception {
        Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

        KeyPair pair = generateRSAKeyPair();
        X509Certificate cert = generateV3Certificate(pair);
        cert.checkValidity(new Date());
        cert.verify(cert.getPublicKey());
    }

    public static KeyPair generateRSAKeyPair() throws Exception {
        KeyPairGenerator kpGen = KeyPairGenerator.getInstance("RSA", "BC");
        kpGen.initialize(1024, new SecureRandom());
        return kpGen.generateKeyPair();
    }
}