---
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
  - Schannel
  - mbedTLS
  - wolfSSL
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 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 result;
    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");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
~~~

# %AVAILABILITY%

# 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).