CAP Calculator
Derive Chip Authentication Programme (CAP / DPA) one-time passcodes from the card's GENERATE AC response and Issuer Proprietary Bitmap — identify, respond and sign readers.
Follows EMV-CAP / DPA one-time code (reader side)IPB bit filter over CID ∥ ATC ∥ AC ∥ IAD·verified Oct 2026· double-checked Oct 2026— matches the python-emv reference; there is no public EMV-CAP specification
Use test data only. All calculations run locally in your browser — PayProbe never sees, transmits, or stores your PAN, CVV, keys, PINs, or cryptographic inputs. How we handle data →
GENERATE AC with Unpredictable Number and amount set to zero.
GENERATE AC response from the card
About CAP / DPA
CAP (Chip Authentication Programme, Mastercard) and DPA (Dynamic Passcode Authentication, Visa) turn an EMV card into an OTP token. The reader asks the card for an ARQC with GENERATE AC, then keeps only the bits of CID ‖ ATC ‖ AC ‖ IAD that the card's Issuer Proprietary Bitmap marks, and shows them as a decimal number. The cryptogram itself is computed by the card with its AC key — use the ARQC Calculator to reproduce it. There is no public EMV-CAP specification; some issuers customise the scheme. Limitation: some issuers set card flags (e.g. Issuer Authentication Flags, 9F55) that make the reader put the PAN Sequence Number in front of the code; this calculator shows only the IPB-selected value and does not add that prefix.