I was randomly experimenting with my new RFID RC522 sensor and was reading info of some random cards. For the cards wich came with the scanner it's even reading the block data .For some cards I could read the UID (not the blocks) but in some RFID enabled cards(Eg: my institute ID card), it's not even showing the uid. Is there anything they have done to prevent scanning it? Or is it an issue with my code or my power supply? I am using
this library and the Dump info example for reading the data.
Reading questions and replies regarding RFID it's pointed out that different technical approaches exist. Different RF frequency is one. While waiting, make a dive into the basic theories.
@newtronmalayalam
The short answer - there are a lot of different types RFID card exists. Some of them are not compatible with your reader.
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can we somehow know which reader is compatible with my card??
Because the bank cards are being scanned(which is supposed to be more secure than the institute cards).
Like can I change the operating frequency or the protocol by program??
No, the antenna on the RC522 module is tuned to a specific frequency.
if you mean a credit or debit card from your bank - you will need another card reader. For example one with a PN532. Be aware of faked ICs and buy from reliable shops only.
You could try downloading a free NFC app on your phone and seeing if that sheds a little more light on what's going on in your particular instance.
If you bought the typical Mifare reader and cards at 13.56MHz, you won't be able to read a lot (probably most) cards that are intended for professional, secure applications. Or most cats. If you could even herd them, that is 
. Pet ID chips also work on a different frequency (125, 128 or 134.2 kHz).