Java tutorial
import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.InputStream; 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.CertificateFactory; import java.security.cert.X509Certificate; import java.util.ArrayList; import java.util.Collection; import java.util.Date; import java.util.Iterator; import javax.security.auth.x500.X500Principal; import org.bouncycastle.x509.X509V1CertificateGenerator; public class MainClass { public static void main(String[] args) throws Exception { Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider()); KeyPair pair = generateRSAKeyPair(); ByteArrayOutputStream bOut = new ByteArrayOutputStream(); bOut.write(generateV1Certificate(pair).getEncoded()); bOut.close(); InputStream in = new ByteArrayInputStream(bOut.toByteArray()); CertificateFactory fact = CertificateFactory.getInstance("X.509", "BC"); X509Certificate x509Cert; Collection collection = new ArrayList(); while ((x509Cert = (X509Certificate) fact.generateCertificate(in)) != null) { collection.add(x509Cert); } Iterator it = collection.iterator(); while (it.hasNext()) { System.out.println("version: " + ((X509Certificate) it.next()).getVersion()); } } public static X509Certificate generateV1Certificate(KeyPair pair) throws InvalidKeyException, NoSuchProviderException, SignatureException { Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider()); X509V1CertificateGenerator certGen = new X509V1CertificateGenerator(); 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"); return certGen.generateX509Certificate(pair.getPrivate(), "BC"); } public static KeyPair generateRSAKeyPair() throws Exception { KeyPairGenerator kpGen = KeyPairGenerator.getInstance("RSA", "BC"); kpGen.initialize(1024, new SecureRandom()); return kpGen.generateKeyPair(); } }