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dCVV Calculator

Calculate Dynamic Card Verification Value (dCVV) for contactless EMV transactions using PAN, expiry, ATC, and CVK keys

🛡️ Authorized QA & Sandbox Testing Only: This developer utility is provided strictly for contactless EMV certification, HSM verification, and sandbox testing using non-production test vectors and dummy Card Verification Keys (CVKs).
💳 Card Data

13–19 digit card number. Spaces are allowed.

4-digit expiry in YYMM format.

1–4 hex characters (EMV Tag 9F36). Increments per transaction.

🔑 Card Verification Keys

8-byte DES key (16 hex chars).

8-byte DES key (16 hex chars).

How it works: The dCVV (dynamic Card Verification Value) uses the same 2-key Triple DES algorithm as CVV, but replaces the static 3-digit service code with the ATC (Application Transaction Counter) — a value that increments with each contactless transaction.

Data string: The full PAN (including check digit) is concatenated with the expiry (YYMM) and the ATC (converted to decimal, zero-padded to 5 digits), then zero-padded to 32 characters. This is split into two 8-byte blocks: Block A is DES encrypted with CVK-A, XORed with Block B, then 3DES encrypted with CVK-A+CVK-B. The result is decimalized to produce a 3-digit code.

vs. CVV/iCVV: While CVV uses service code 101 and iCVV uses 999, dCVV uses the ATC to generate a unique code per transaction — preventing replay attacks in contactless MSD environments.

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📖 About This Tool

What is the dCVV Calculator?

The dCVV Calculator computes Dynamic Card Verification Values used in contactless MSD transactions. Unlike static CVV, dCVV changes with each transaction using the Application Transaction Counter (ATC), preventing replay attacks.

🛠️ How to Use
  1. Enter the Primary Account Number (PAN, 13–19 digits) and 4-digit expiry date (YYMM).
  2. Enter the Application Transaction Counter (ATC) in hexadecimal (1–4 hex characters).
  3. Enter the two 8-byte Card Verification Keys (CVK-A and CVK-B, 16 hex characters each).
  4. The 3-digit dCVV is calculated automatically in real time.
❓ FAQ

What is dCVV?

dCVV (Dynamic Card Verification Value) is a one-time CVV generated for each contactless transaction by replacing the static service code with the incrementing ATC (Application Transaction Counter). It prevents intercepted Track 2 magnetic stripe data from being replayed.