which protocol is used (other than NDEF protocol) for communication between Mifare classic 1k and nfc enabled mobile, when we raed or write indvisual blocks.
NDEF is not a communication protocol, but the message content description:
"...The NDEF specification defines a message encapsulation format to exchange information... NDEF is a lightweight, binary message format that can be used to encapsulate one or more application-defined payloads of arbitrary type and size into a single message construct. Each payload is described by a type, a length, and an optional identifier. Type identifiers may be URIs, MIME media types, or NFC-specific types..."
The protocol to read/write Mifare sectors is a proprietary see e.g. here: https://www.nxp.com/docs/en/data-sheet/MF1S50YYX_V1.pdf
BR STeN