Introduction HMAC is widely for securing access to content with expirable tokens. HMAC stands for Hash-Based Message Authentication Code and the goal of this article is to learn how to manipulate and use HMAC tokens in combination with Cloudflare. Cloudflare mostly provides two ways to deal with HMAC tokens: Firewall rules https://developers.cloudflare.com/firewall/recipes/require-valid-hmac-token/ Workers (Cloudflare’s Serverless platform) - https://developers.cloudflare.com/workers/examples/signing-requests/ The first thing to know about HMAC is actually how to use it efficiently.