Arqc-gen.exe
If you or your organization work with this tool, follow these strict guidelines:
| Practice | Reason | |----------|--------| | Use only test keys | Real issuer master keys (IMKs) would be a catastrophic leak. | | Run on air-gapped machines | Prevent network exfiltration of generated cryptograms. | | Log all executions | Audit trail for who generated which ARQC, when. | | Never process production PANs | Even test ARQCs with real PANs could be used in phishing. | | Wipe memory after use | Session keys persist only during execution; ensure no core dumps. |
The tool will output the 8-byte (16 hex character) cryptogram. arqc-gen.exe
Because arqc-gen.exe can generate valid-looking ARQCs, it can be a double-edged sword.
Starting around 2015, cybercriminals modified legitimate EMV test tools to create arqc-gen.exe variants. These versions are often: If you or your organization work with this
arqc-gen.exe is the cryptographic equivalent of a lockpick set. In the hands of an EMV engineer testing a new terminal, it is a legitimate, necessary tool. In the hands of a criminal equipped with compromised keys, it is a powerful fraud enabler.
For the average consumer, you will never see this file. If you work in payment security, treat every instance outside a locked lab as a red flag requiring immediate incident response. The future of card security – with tokenization, biometric authentication, and point-to-point encryption – aims to make ARQC generators obsolete. But for now, this tiny executable sits at a fascinating, dangerous intersection of cryptography and crime. The tool will output the 8-byte (16 hex
Final recommendation: Remove any unapproved copy of arqc-gen.exe from your network, report it, and verify that no unauthorized EMV key material has been exposed. Stay safe.
This article is for educational and defensive purposes only. The author does not endorse the illegal use of cryptographic tools.
| Step | Process | Output |
|------|---------|--------|
| 1 | Derive Session Key (UDK from IMK + PAN + CSN) | Session Key: AB... |
| 2 | Build ARQC data (ATC + Unpredictable + Amount...) | Data: 0001 1234ABCD 00001000... |
| 3 | Compute CMAC or CBC MAC (depending on algorithm) | MAC: 4F2A98C3 |
| 4 | Format final ARQC | ARQC: 4F2A98C3 12F1B9A0 |
The ARQC generation requires a specific concatenation of data elements defined by EMV specifications (usually involving tags like 9F02, 9F03, 9F1A, 95, 5F2A, 9A, 9C, 9F37, etc.).