Talk to your Credit Card part 7 (final app)

This app shows how to talk with a Credit Card and get information's like the Credit Card number, the card's expiration date and some other data.

The description can be found in an article series on medium.com: https://medium.com/@androidcrypto/talk-to-your-credit-card-part-7-find-and-print-out-the-application-primary-account-number-52b24b396082

• general overview about the app
• ask the card which applications are available on the card ("select PPSE")
• analyze the card's response and identify one or more of the application number or application id ("AID")
• select one application on the card to work with ("select AID") [or iterate through the applications and run the following steps for each application]
• analyze the card's response to find out what data the card needs to proceed (find the "processing options data object list" (PDOL))
• analyze the card's response and get the content of the element "application file locator" (AFL) list
• read all files given in the AFL list and find the file where there are the elements "Application Primary Account Number" and "Application Expiration Date"
• print out the "Application Primary Account Number" ("PAN") = card number and "Application Expiration Date" = expiration date of the card.

The app uses the NFC ReaderMode to get access to the card.

There are apps available for each step in my GitHub repository - the naming shows the step that has the code including this step.

This is the app for the (final) seventh step 7: find and print out the "Application Primary Account Number" ("PAN") = card number in TalkToYourCreditCardPart7.

The app is tested on real Android devices running Android versions 5.0.1, 8.0, 9 and 13.

A compiled version of the app is available in the "debug-release" folder of this repository:

These are the steps to read a payment card, it is a kind of "question & answer" workflow:

• ask the card which applications are available on the card ("select PPSE")
• analyze the card's response and identify one or more of the application number or application id ("AID")
• select one application on the card to work with ("select AID") [or iterate through the applications and run the following steps for each application]
• analyze the card's response to find out what data the card needs to proceed (find the "processing options data object list" (PDOL))
• analyze the card's response and get the content of the element "application file locator" (AFL) list
• read all files given in the AFL list and find the file where there are the elements "Application Primary Account Number" and "Application Expiration Date"
• print out the "Application Primary Account Number" ("PAN") = card number and "Application Expiration Date" = expiration date of the card.

Version Update September 2024

This is the updated version of the "Talk to your Credit Card app". The main change is in the new Gradle Environment version 8.7. The target and compiled SDK is still SDK 33 as I can't test on SDK 34 devices.

A minor change is feature update in the "Read Files" part. The log file now prints out the SFI and file number of the file - that makes it easier for everyone that need the file data for e.g. emulating a Credit Card:

readRecord SFI 20 file 2 command length: 5 data: 00b2022400
...

Screenshot of the app

In AndroidManifest.xml grant these permissions:

    <uses-permission android:name="android.permission.NFC" />
    <uses-permission android:name="android.permission.VIBRATE" />

There are 3 dependencies necessary for the app to run:

build.gradle:

    // parsing BER-TLV encoded data, e.g. a credit card
    // source: https://github.com/evsinev/ber-tlv
    implementation 'com.payneteasy:ber-tlv:1.0-11'
    
    // pretty printing of card's responses
    // source: https://github.com/devnied/EMV-NFC-Paycard-Enrollment
    implementation 'com.github.devnied.emvnfccard:library:3.0.1'
    
    // implementing an about page
    implementation 'io.github.medyo:android-about-page:2.0.0'

Library ber-tlv

Source code: https://github.com/evsinev/ber-tlv

License: Apache-2.0 license

Library: EMV-NFC-Paycard-Enrollment

Source code: https://github.com/devnied/EMV-NFC-Paycard-Enrollment

License: Apache-2.0 license

Library: Android About Page

Source code: https://github.com/medyo/android-about-page

License: The MIT License (MIT)

Sound resources for pings

https://m2.material.io/design/sound/sound-resources.html

Licensed under Attribution 4.0 International (CC BY 4.0): https://creativecommons.org/licenses/by/4.0/legalcode

Find a complete logfile after reading a Credit Card with the app with the link.