Expiration check on PGP key

[OxMarco]

I noticed when parsing a PGP key there is a property named v3_days_of_validity, how can it be used to determine the key validity and is it compatible with most generation algorithms?

[singpolyma]

v3_days_of_validity is only for v3 keys, of which there are very few in the wild. In general what you will actually want is to look for a OpenPGP_SignaturePacket_KeyExpirationTimePacket inside a self-signature on the key.