PrivateKey signingKey = (PrivateKey)ks.getKey(privateKeyAlias, privateKeyPass.toCharArray());
X509Certificate cert = (X509Certificate)ks.getCertificate(certificateAlias);
// Create the entry to sign
Abdera abdera = new Abdera();
AbderaSecurity absec = new AbderaSecurity(abdera);
Factory factory = abdera.getFactory();
Entry entry = factory.newEntry();
entry.setId("http://example.org/foo/entry");
entry.setUpdated(new java.util.Date());
entry.setTitle("This is an entry");
entry.setContentAsXhtml("This <b>is</b> <i>markup</i>");
entry.addAuthor("James");
entry.addLink("http://www.example.org");
// Prepare the digital signature options
Signature sig = absec.getSignature();
SignatureOptions options = sig.getDefaultSignatureOptions();
options.setCertificate(cert);
options.setSigningKey(signingKey);
// Sign the entry