Encrypting file with an expired public key

[aiscrim]

I am using this library to encrypt a zip file. The code is very simple:

using (PGP pgp = new PGP())
{
    pgp.EncryptFile(zipFileFullname, encryptedFileFullname, publicKeysFileFullname);
}

It generally works well, but today I noticed that if I use an expired public key, it successfully encrypts the file regardless of the key being expired, without any warning. I have been looking for some parameters to be passed or some methods to call to verify if the keys are valid, but I didn't find anything. Isn't the encryption supposed to fail if the encryption keys expired?

[mattosaurus]

As far as I can tell encryption/decryption of a file encrypted with an expired public key should still work as normal though there should potentially be a warning that the key has expired.

I'm not sure of the best way to handle this but I might add another parameter to the methods to determine the behaviour of expired keys.