gchq/CyberChef

Operation request: ISO14443 SmartCards algorithms (CRC16, BCC)

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#9 opened on Nov 29, 2016

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 (3 comments) (4 reactions) (0 assignees)JavaScript (3,944 forks)batch import
help wantedoperation

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Description

Thank you for great tool!

It will be nice to see algorithms from ISO14443 and ISO13239 contactless smartcards standards.

  • CRC16_A Initial register 0x6363 or 0xC6C6 in reversed bit order. Polynomial is 0x1021 and no final XOR.
  • CRC16_B
  • BCC (Bit Count Check) — simple successively XOR-ing all bytes

I've made my own calculator for example https://hub.zhovner.com/tools/nfc/

Contributor guide

Research direction
Review existing CRC operations in CyberChef's source code to understand the pattern, then implement CRC16 A, CRC16 B, and BCC for ISO14443.
Tech stack
javascript
Domain
security
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
CRCJavaScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75