.\" generated by cd2nroff 0.1 from CURLOPT_SSLKEY_BLOB.md
.TH CURLOPT_SSLKEY_BLOB 3 "2026-06-24" libcurl
.SH NAME
CURLOPT_SSLKEY_BLOB \- private key for client cert from memory blob
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLKEY_BLOB,
                          struct curl_blob *blob);
.fi
.SH DESCRIPTION
Pass a pointer to a curl_blob structure, which contains information (pointer
and size) for a private key. Compatible with OpenSSL. The format (like "PEM")
must be specified with \fICURLOPT_SSLKEYTYPE(3)\fP.

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 \fICURLOPT_SSLKEY(3)\fP which instead expects a
filename as input.
.SH DEFAULT
NULL
.SH PROTOCOLS
This functionality affects  all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc. only

This option works only with the following TLS backends:
OpenSSL and wolfSSL
.SH EXAMPLE
.nf

extern char *certificateData; /* point to cert */
extern size_t filesize; /* size of cert */

extern char *privateKeyData; /* point to key */
extern size_t privateKeySize; /* size of key */

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    struct curl_blob blob;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    blob.data = certificateData;
    blob.len = filesize;
    blob.flags = CURL_BLOB_COPY;
    curl_easy_setopt(curl, CURLOPT_SSLCERT_BLOB, &blob);
    curl_easy_setopt(curl, CURLOPT_SSLCERTTYPE, "PEM");

    blob.data = privateKeyData;
    blob.len = privateKeySize;
    curl_easy_setopt(curl, CURLOPT_SSLKEY_BLOB, &blob);
    curl_easy_setopt(curl, CURLOPT_KEYPASSWD, "s3cret");
    curl_easy_setopt(curl, CURLOPT_SSLKEYTYPE, "PEM");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
.fi
.SH AVAILABILITY
Added in curl 7.71.0
.SH RETURN VALUE
\fIcurl_easy_setopt(3)\fP returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non\-zero means an error occurred, see
\fIlibcurl\-errors(3)\fP.
.SH SEE ALSO
.BR CURLOPT_SSLKEY (3),
.BR CURLOPT_SSLKEYTYPE (3)