NFC APDU READ Performance Tuning

Question

I read several hundred bytes from a DESFire card using APDU commands.

The data application is authenticated, and the response is MAC'ed.

I present a series of READ_DATA (0xBD) commands, each of which extracts 54 bytes + MAC, increasing the read offset for each command.

Will this operation work much faster if I use a long READ with ADDITIONAL_FRAME (AF) instead of many consecutive readings?

I understand that simple AF is 1 byte versus 8 bytes for the full READ DATA command, thus reducing the number of bytes transmitted by ~ 10%. But using AF will provide additional performance benefits, for example, due to less processing needed for the card?

I ask about this since I get an effective bit rate of only ~ 220 kbps when the theoretical limit is 424 kbps. See my question about it here.

Answer 1

I changed my readings to use EXTRA FRAME.

This reduced the total number of sent + bytes received from 1628 to 1549 bytes by 5%.

The time taken by tranciecve () decreased from 602 ms to 593 ms, a decrease of 1.5%.

The conclusion is that using AF will not give additional performance to others, which is reduced time for transmitted bytes.

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Answer 2

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