---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_PROXY_CAINFO_BLOB
Section: 3
Source: libcurl
See-also:
  - CURLOPT_CAINFO (3)
  - CURLOPT_CAINFO_BLOB (3)
  - CURLOPT_CAPATH (3)
  - CURLOPT_PROXY_CAINFO (3)
  - CURLOPT_PROXY_CAPATH (3)
  - CURLOPT_PROXY_SSL_VERIFYHOST (3)
  - CURLOPT_PROXY_SSL_VERIFYPEER (3)
  - CURLOPT_SSL_VERIFYHOST (3)
  - CURLOPT_SSL_VERIFYPEER (3)
Protocol:
  - TLS
TLS-backend:
  - OpenSSL
  - rustls
  - Secure Transport
  - Schannel
Added-in: 7.77.0
---

# NAME

CURLOPT_PROXY_CAINFO_BLOB - proxy Certificate Authority (CA) bundle in PEM format

# SYNOPSIS

~~~c
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_CAINFO_BLOB,
                          struct curl_blob *stblob);
~~~

# DESCRIPTION

This option is for connecting to an HTTPS proxy, not an HTTPS server.

Pass a pointer to a curl_blob structure, which contains information (pointer
and size) about a memory block with binary data of PEM encoded content holding
one or more certificates to verify the HTTPS proxy with.

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.

If CURLOPT_PROXY_SSL_VERIFYPEER(3) is zero and you avoid verifying the
server's certificate, CURLOPT_PROXY_CAINFO_BLOB(3) is not needed.

This option overrides CURLOPT_PROXY_CAINFO(3).

# DEFAULT

NULL

# %PROTOCOLS%

# EXAMPLE

~~~c
#include <string.h> /* for strlen */

extern char *strpem; /* strpem must point to a PEM string */
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    struct curl_blob blob;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    /* using an HTTPS proxy */
    curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost:443");
    blob.data = strpem;
    blob.len = strlen(strpem);
    blob.flags = CURL_BLOB_COPY;
    curl_easy_setopt(curl, CURLOPT_PROXY_CAINFO_BLOB, &blob);
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
~~~

# %AVAILABILITY%

# RETURN VALUE

Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.