Fiserv Payment Demo

HMAC-SHA256 Hash Generator

Use this tool to manually generate and verify HMAC-SHA256 hashes for Fiserv payment forms.

Instructions
  1. Copy the hashDataString from the payment redirect page
  2. Paste it into the "Text to Hash" field
  3. Enter your shared secret key
  4. Click "Generate Hash" to create the HMAC-SHA256 hash
  5. Compare the result with the hashExtended value from the payment form
Security Note

This tool is for testing purposes only. Never use it with production secret keys in a public environment.