How come this setting causes signature mismatch? I am implementing replay attack prevention for GC webhooks. The docs state: “Use the X-Genesys-Signature header to verify the request origin using HMAC-SHA256.” My C# code extracts the header and computes HMAC using the app secret, but the result never matches the header value. I am using HMACSHA256 with UTF8 encoding. The header format seems correct. Am I missing a timestamp check or encoding step? The Azure Function returns 401 Unauthorized because validation fails.
I’d suggest checking out at the payload encoding. The docs specify raw bytes, not UTF8 strings, for HMAC-SHA256. Using Encoding.UTF8.GetBytes on the JSON string often causes mismatches if the webhook sends raw bytes. Check Genesys Webhook Security Docs. Ensure you hash the exact body bytes received.