DescriptionVerify if One-Time Counters (OTP) are changed on a NFC Ultralight card. THIS APP ONLY WORKS ON PHONES WITH NFC! UltraCardTester will show you the OTP value and number of unset bit remaining on a card. It will save these values so it can then compare the card again after use.
Tap Ultralight card to Android device (ensure screen states the data was saved).
Next use the Ultralight card as intended.
Finally, tap the Ultralight card back to the phone to view if the card data has changed.
This app can help determine if a system using Ultralight cards may be susceptible to reset attacks.