RIFD door unlocking system: Need help understanding the RFID libaries

Using Arduino Project Guidance
1

I am going to make an RIFD controlled door unlocking system using a servo as the deadbolt actuator. I purchased a Sunfounder Mifare RC522 Module RFID Reader today, and after purchasing realized the documentation link does not work. I went to google to search for the needed libraries but am having trouble figuring out how to use them. Sure this project has been done before and there is code posted online which I could use, but I'd like to understand what I'm doing. Also, it was mentioned for all the the libraries I saw (all of which were probably the exact same) that encryption is not supported. So I have two favors to ask:

1st could someone explain to me the 'functions' that can be called from the MFRC522 library(what they do? how to use them?)

2nd does anyone know of a mfrc522 library that supports encryption? or can I implement it on my own? (probably beyond my skill level!)

This is a link to the library I plan on using: GitHub - miguelbalboa/rfid: Arduino RFID Library for MFRC522

For the unlocking program I believe all I really need to do with RIFD part is to read in the code and then check it against a data base of codes that I code into the Arduino. Right?

Also, someone stated in a review of this reader that it supports NFC through smart phones. Does that require a different library?

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I don't have an answer on the library question, but something you might want to consider is adding "valid times" and even possibly "vacation" or some such to the database so you can give someone else a key for example to get into the house, but it is only valid from 8AM to 9PM or something like that. Another checkbox you could set for "vacation" that deactivates all other keys until you get home and switch back to normal. Just a couple of thoughts I had when I was thinking about doing one for my house.

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If cards can only be distinuished by their changeable content, you have a security problem (by copy or replay of the card content) that can not be circumvented by any encryption. And I fear that could be the case.

RFID smartcard USB Port Smart Card Reader & Writer with UID writable clone Mifare IC Access Control Card ISO 14443
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