new XMLSignature(sigElement, f.toURI().toURL().toString());
// signature.addResourceResolver(new OfflineResolver());
byte keybytes[] = "secret".getBytes("ASCII");
javax.crypto.SecretKey sk = signature.createSecretKey(keybytes);
System.out.println("The XML signature in file "
+ f.toURI().toURL().toString() + " is "
+ (signature.checkSignatureValue(sk)
? "valid (good)" : "invalid !!!!! (bad)"));