--- title: "HTTP Message Signatures with curl" url: https://daily.dev/posts/http-message-signatures-with-curl-ede6ylmsp source_url: https://daniel.haxx.se/blog/2026/07/27/http-message-signatures-with-curl type: article source: "daniel.haxx.se" published: 2026-07-27T06:59:51.383Z updated: 2026-07-27T07:00:10.793Z tags: ["curl"] reading_time: 3 upvotes: 12 comments: 1 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # HTTP Message Signatures with curl **[daniel.haxx.se](https://daily.dev/sources/danielhaxxse)** · 3 min read · 12 upvotes · 1 comments ## Summary curl now experimentally supports HTTP Message Signatures as defined in RFC 9421, starting with the upcoming 8.22.0 release. The feature enables digital signing of selected HTTP request components (headers, method, path, etc.) to ensure they arrive unmodified through proxies, CDNs, and other intermediaries. Four new command-line options are introduced: --httpsig-algo (defaulting to ed25519, with hmac-sha256 also supported), --httpsig-key, --httpsig-keyid, and --httpsig-headers. Equivalent libcurl options are available via curl_easy_setopt. The feature is marked experimental, must be explicitly enabled at build time, and backward compatibility is not guaranteed until it exits the experimental phase. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [curl 8.16.0](https://daily.dev/posts/curl-8-16-0-fz7yy9jmn) · daniel.haxx.se · 3 upvotes · 0 comments - [curl 8.21.0](https://daily.dev/posts/curl-8-21-0-nk89ow7op) · daniel.haxx.se · 6 upvotes · 0 comments - [curl 8.17.0](https://daily.dev/posts/curl-8-17-0-y2csfmgw0) · daniel.haxx.se · 1 upvotes · 0 comments --- Tags: [#curl](https://daily.dev/tags/curl) [View this post on daily.dev](https://daily.dev/posts/http-message-signatures-with-curl-ede6ylmsp)