---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_SSLCERT_BLOB
Section: 3
Source: libcurl
See-also:
  - CURLOPT_KEYPASSWD (3)
  - CURLOPT_SSLCERTTYPE (3)
  - CURLOPT_SSLKEY (3)
Protocol:
  - TLS
TLS-backend:
  - OpenSSL
  - Secure Transport
  - Schannel
  - mbedTLS
Added-in: 7.71.0
---

# NAME

CURLOPT_SSLCERT_BLOB - SSL client certificate from memory blob

# SYNOPSIS

~~~c
#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
expects a filename as input.

# DEFAULT

NULL

# %PROTOCOLS%

# EXAMPLE

~~~c

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%

# RETURN VALUE

Returns CURLE_OK if TLS enabled, CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.
