CURLOPT_SSLCERT_BLOB(3) Library Functions Manual CURLOPT_SSLCERT_BLOB(3)
NAME
CURLOPT_SSLCERT_BLOB - SSL client certificate from memory blob
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLCERT_BLOB,
struct curl_blob *stblob);
DESCRIPTION
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 format
must be "DER" or "PEM" on mbedTLS. The format 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 setting this.
This option is an alternative to CURLOPT_SSLCERT(3) which instead ex-
pects a filename as input.
DEFAULT
NULL
PROTOCOLS
This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS,
POP3S, SMTPS etc.
This option works only with the following TLS backends: OpenSSL, Schan-
nel, Secure Transport, mbedTLS and wolfSSL
EXAMPLE
extern char *certificateData; /* point to data */
extern size_t filesize; /* size of data */
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode res;
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");
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
AVAILABILITY
Added in curl 7.71.0
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).
SEE ALSO
CURLOPT_KEYPASSWD(3), CURLOPT_SSLCERTTYPE(3), CURLOPT_SSLKEY(3)
libcurl 2026-07-12 CURLOPT_SSLCERT_BLOB(3)
Generated by dwww version 1.16 on Sat Oct 3 05:45:54 CEST 2026.