P1 PIN blocks
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ISO 9564 formats 0 to 4: building, encrypting, decoding and translating PIN blocks.
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What this module covers
You will be able to
- Build and decode ISO formats 0, 1, 2, 3 and 4
- Take the right 12 PAN digits
- Encrypt and decrypt a PIN block
- Explain translation between formats and keys, and why some translations are forbidden
The lesson
- Why it matters
- The concept
- Step by step: ISO 0
- Translation
- In the real world
- Common mistakes
- What to test
In the module
- The lesson, with diagrams, common mistakes and what to test
- A worked example you can change: Building and encrypting a PIN block
- Practice: 5 kinds of generated exercise, each with a step-by-step solution
- A quiz of 9 questions
Key terms
- ISO format 0
- The common PIN block: a PIN field (0, length, PIN, F fill) XORed with a PAN field (0000 and the 12 rightmost PAN digits without the check digit).
- ISO format 1
- A PIN block without the PAN: 1, length, PIN, random fill. Used where the PAN is not available.
- ISO format 2
- A PIN block for offline PIN sent to a chip card: 2, length, PIN, F fill. Not for online use.
- ISO format 3
- Like format 0 but with random fill digits from A to F, so equal PINs on the same card give different blocks.
- ISO format 4
- The 16-byte AES PIN block: a PIN field and a PAN field of 16 bytes each, combined with two AES encryptions.
- PIN block
- The 8- or 16-byte block that carries an encrypted PIN, combining the PIN with fill digits and often the PAN, in one of the ISO 9564 formats.
- PIN translation
- Decrypting a PIN block under one key and re-encrypting it under another, possibly in another format, inside an HSM. The PIN is never in the clear outside it.
The lesson, worked example, practice and quiz open with a supporter pass, which you can try free for 7 days.