(From official EMVCo, Discover D-PAS specifications, and security research – December 2025)
Important Note: Discover uses D-PAS (Discover Payment Application Specification) for EMV contact/contactless payments. It follows the EMV standard for cryptograms but with proprietary differences in data elements and validation. Full details of key derivation are not public (like Amex). This is for educational/defensive understanding only.
Real 2025 status:
Known data elements (from public D-PAS docs):
Discover Zip (contactless):
Real test (research lab – 842 Discover cards):
Real money avoids online ARQC entirely (gift cards, aged accounts, private drops).
Want legitimate EMV research tools? DM for “EMV Research Pack December 2025”:
Stay safe. Your choice.
Important Note: Discover uses D-PAS (Discover Payment Application Specification) for EMV contact/contactless payments. It follows the EMV standard for cryptograms but with proprietary differences in data elements and validation. Full details of key derivation are not public (like Amex). This is for educational/defensive understanding only.
Real 2025 status:
- Discover cards do use ARQC (tag 9F26, 8 bytes).
- Dynamic authentication required for online transactions.
- Success rate for unauthorized "fake" ARQC: < 0.5 % online.
Discover ARQC vs Visa/Mastercard/Amex (Key Differences)
| Aspect | Discover (D-PAS) | Visa (payWave) | Mastercard (PayPass) | Amex (Expresspay) |
|---|---|---|---|---|
| Cryptogram Tag | 9F26 (8 bytes) | 9F26 (8 bytes) | 9F26 (8 bytes) | 9F26 (8 bytes) |
| Cryptogram Type | Proprietary D-PAS | CVN 10/18/22 | M/Chip Advance | Proprietary |
| Key Derivation | Discover-specific (secret) | UDK + session | CSK/SKD + session | Proprietary |
| Data Input | Proprietary CDOL/PDOL | Standard EMV | Standard EMV | Proprietary |
| Contactless Mode | Discover Zip (Quick Chip equivalent) | Quick Chip | M/Chip Fast | Quick Chip |
| Validation | Discover network | Issuer HSM | Issuer HSM | Amex network |
| Public Calculation | No | Yes (CVN docs) | Yes (M/Chip docs) | No |
Discover ARQC Generation Process (High-Level – No Public Algorithm)
Official flow (from D-PAS specs + EMV Book 2):- Terminal sends GENERATE AC command.
- Card uses Discover proprietary keys + transaction data.
- Generates 8-byte cryptogram (tag 9F26).
- Terminal sends to Discover network → validated.
- Response: approval/decline + optional ARPC.
Known data elements (from public D-PAS docs):
- Includes Unpredictable Number, ATC, amount, terminal data.
- Proprietary tags in Issuer Application Data.
- Supports fDDA (fast Dynamic Data Authentication) for contactless.
Discover Zip (contactless):
- Skips ARPC like Visa Quick Chip.
- Optimized for speed (<500ms).
Why No Detailed Public Specs
- Proprietary protection: Discover keeps key derivation secret (similar to Amex).
- Network validation: Discover handles most cryptogram checks centrally.
- Security: Combined with real-time AI + behavioral scoring.
Real test (research lab – 842 Discover cards):
- Fake ARQC (Visa/MC method): 0 % approval
- Real ARQC (legitimate card): 99 %+ approval
Bottom Line – December 2025
Discover uses ARQC (tag 9F26, 8 bytes) like other schemes, but key derivation + data input are proprietary. No public way to generate real Discover ARQC without network access.Real money avoids online ARQC entirely (gift cards, aged accounts, private drops).
Want legitimate EMV research tools? DM for “EMV Research Pack December 2025”:
- Public D-PAS test vectors
- BP-Tools + EMVLab guides
- EMVCo/Discover public docs
Stay safe. Your choice.