Section: curl_easy_setopt options (3)
Updated: November 04, 2020
CURLOPT_SSLCERT_BLOB - SSL client certificate from memory blob
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLCERT_BLOB, struct curl_blob *stblob);
Pass a pointer to a curl_blob structure, which contains (pointer and size) a
client certificate. The format must be "P12" on Secure Transport or
Schannel. The format must be "P12" or "PEM" on OpenSSL. The string "P12" or
"PEM" must be specified with CURLOPT_SSLCERTTYPE(3)
If the blob is initialized with the flags member of struct curl_blob set to
CURL_BLOB_COPY, the application does not have to keep the buffer around after
This option is an alternative to CURLOPT_SSLCERT(3) which instead
expects a file name as input.
All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
CURL *curl = curl_easy_init();
struct curl_blob stblob;
stblob.data = certificateData;
stblob.len = filesize;
stblob.flags = CURL_BLOB_COPY;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
curl_easy_setopt(curl, CURLOPT_SSLCERT_BLOB, &stblob);
curl_easy_setopt(curl, CURLOPT_SSLCERTTYPE, "P12");
curl_easy_setopt(curl, CURLOPT_KEYPASSWD, "s3cret");
ret = curl_easy_perform(curl);
Added in libcurl 7.71.0. This option is supported by the OpenSSL, Secure
Transport and Schannel backends.
Returns CURLE_OK if TLS enabled, CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.