Module 4 of 22 · Practitioner · 150 min
Communication process for EMV transactions
The APDU protocol end to end: packet generation, commands, responses, and the structure at the core of every transaction.
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Open the free workbench →What this module covers
- 01The protocol is not encrypted
- 02Two layers, and why a log is twice as long as the conversation
- 03The command APDU, byte by byte
- 04CLA: who defined this command
- 05P1 and P2: the bytes with no general meaning
- 06The four cases
- 07The response, and the status word
- 08Reading a status word as a sentence
- 09Le, and the two-step read
- 10The transaction, end to end
- 11BER-TLV: how the card structures an answer
- 12Data Object Lists: the card asking the terminal a question
- 13A command that expects no answer
- 14Where this goes next