NAME

CURLOPT_HTTPSIG_ALGORITHM - RFC 9421 HTTP Message Signatures algorithm

SYNOPSIS

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HTTPSIG_ALGORITHM,
                          long algorithm);

DESCRIPTION

This feature is experimental and may change before it is considered stable. We advise against using it in production.

Enable RFC 9421 HTTP Message Signatures on outgoing requests. Pass a long set to one of the values below to select the signing algorithm.

CURLHTTPSIG_NONE (0): Disable HTTP Message Signatures.
CURLHTTPSIG_ED25519 (1): Sign with Ed25519 (RFC 8032). Requires a TLS backend with Ed25519 support.
CURLHTTPSIG_HMAC_SHA256 (2): Sign with HMAC-SHA256.

Setting this option to a non-zero value also sets CURLOPT_HTTPAUTH(3) to CURLAUTH_HTTPSIG. The options CURLOPT_HTTPSIG_KEY(3) and CURLOPT_HTTPSIG_KEYID(3) must also be set.

DEFAULT

CURLHTTPSIG_NONE (0)

PROTOCOLS

This functionality affects http only

EXAMPLE

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/api");
    curl_easy_setopt(curl, CURLOPT_HTTPSIG_ALGORITHM, CURLHTTPSIG_ED25519);
    curl_easy_setopt(curl, CURLOPT_HTTPSIG_KEY,
                     "9f8362f87a484a954e6e740c5b4c0e84"
                     "229139a20aa8ab56ff66586f6a7d29c5");
    curl_easy_setopt(curl, CURLOPT_HTTPSIG_KEYID, "my-key-id");
    curl_easy_perform(curl);
  }
}

AVAILABILITY

Added in curl 8.22.0

RETURN VALUE

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).