public static PKCS10CertificationRequest generateCSR(String[] commonNames, KeyPair pair) throws OperatorCreationException, IOException { X500NameBuilder namebuilder = new X500NameBuilder(X500Name.getDefaultStyle()); namebuilder.addRDN(BCStyle.CN, commonNames[0]); List<GeneralName> subjectAltNames = new ArrayList<>(commonNames.length); for (String cn:commonNames) subjectAltNames.add(new GeneralName(GeneralName.dNSName, cn)); GeneralNames subjectAltName = new GeneralNames(subjectAltNames.toArray(new GeneralName[0])); ExtensionsGenerator extGen = new ExtensionsGenerator(); extGen.addExtension(Extension.subjectAlternativeName, false, subjectAltName.toASN1Primitive()); PKCS10CertificationRequestBuilder p10Builder = new JcaPKCS10CertificationRequestBuilder(namebuilder.build(), pair.getPublic()); p10Builder.addAttribute(PKCSObjectIdentifiers.pkcs_9_at_extensionRequest, extGen.generate()); JcaContentSignerBuilder csBuilder = new JcaContentSignerBuilder("SHA256withRSA"); ContentSigner signer = csBuilder.build(pair.getPrivate()); PKCS10CertificationRequest request = p10Builder.build(signer); return request; }