I'm trying to generate keystore with certificate to use it with JarSigner. Here is my code: System.out.println("Keystore generation..."); Security.addProvider(new BouncyCastleProvider()); String domainName = "example.org"; KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA"); SecureRandom random = SecureRandom.getInstance("SHA1PRNG", "SUN"); keyGen.initialize(1024, random); KeyPair pair = keyGen.generateKeyPair(); X509V3CertificateGenerator v3CertGen = new X509V3CertificateGenerator(); int serial = new SecureRandom().nextInt(); v3CertGen.setSerialNumber(BigInteger.valueOf(serial < 0 ? -1 * serial : serial)); v3CertGen.setIssuerDN(new X509Principal("CN=" + domainName + ", OU=None, O=None L=None, C=None")); v3CertGen.setNotBefore(new Date(System.currentTimeMillis() - 1000L * 60 * 60 * 24 * 30)); v3CertGen.setNotAfter(new Date(System.currentTimeMillis() + (1000L * 60 * 60 * 24 * 365*10))); v3CertGen.setSubjectDN(new X509Principal("CN=" + domainName + ", OU=None, O=None L=None, C=None")); v3CertGen.setPublicKey(pair.getPublic()); v3CertGen.setSignatureAlgorithm("MD5WithRSAEncryption"); X509Certificate PKCertificate = v3CertGen.generateX509Certificate(pair.getPrivate()); FileOutputStream fos = new FileOutputStream("/Users/dmitrysavchenko/testCert.cert"); fos.write(PKCertificate.getEncoded()); fos.close(); KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType()); char[] password = "123".toCharArray(); ks.load(null, password); ks.setCertificateEntry("hive", PKCertificate); fos = new FileOutputStream("/Users/dmitrysavchenko/hive-keystore.pkcs12"); ks.store(fos, password); fos.close(); It works, but when I'm trying to sign my JAR with this keystore, I get the following error: jarsigner: Certificate chain not found for: hive. hive must reference a valid KeyStore key entry containing a private key and corresponding public key certificate chain. I've discovered that there must be a private key, but I don't know how to add it to certificate. Can you help me?