sw9000-android/README.md

sw9000-android

A read-only Android app that reads a contactless EMV card over NFC and shows everything obtainable from it, with full APDU-level transparency. For reading your own cards.

What it does

On launch it checks NFC:

• No NFC hardware → an "NFC not supported" screen.
• NFC off → a prompt with a button to open NFC settings.
• NFC on → the "tap a card" animation (a card swinging onto a phone with NFC ripples, ported from the sibling android app). On tap it reads the card and shows:
  • Formatted — PAN, cardholder name, expiry, valid-from, PAN sequence, application label / preferred name / AID, issuer country, currency, ATC, PIN-try counter, AIP, Track 2, plus the tag's UID / technologies / ATQA / SAK / historical bytes.
  • Raw dump — the full BER-TLV tree (every tag labelled and interpreted) for each application, and the complete APDU log: every command sent, every response, and the decoded status word.

The read flow is: SELECT PPSE → for each advertised AID: SELECT AID → GET PROCESSING OPTIONS (PDOL filled in) → READ RECORD across the AFL → GET DATA for the common counters. It never writes to the card and runs no transaction (no GENERATE AC), so tapping is harmless.

Scheme / country / bank

Derived with no network:

• Scheme (Visa / Mastercard / Amex / UnionPay / JCB / Discover …) — from the application AID's RID and, as a fallback, the PAN's leading digits. Reliable.
• Issuer country — from EMV tag 5F28 (ISO-3166 numeric), decoded to a country name. Present on most cards.
• Issuer bank / card type / product — not stored on the card. Naming the bank needs a BIN/IIN database, which you can optionally bundle at build time: drop a tab-separated dataset at app/src/main/assets/bins.tsv (format documented in that file). It compiles into the APK, so the app still makes no network calls. Without it, the app shows the raw BIN for manual lookup, and the application label (50 / 9F12) often carries the issuer's branding anyway.

Privacy

No network. The app declares only android.permission.NFC — no INTERNET permission, so nothing read from a card can leave the device.

Build

Standard Gradle / Android Studio project (AGP 9, Kotlin 2.2, Jetpack Compose). Needs a physical NFC-capable device; the emulator can't read cards.