---
name: "CURLOPT_PROXY_SSL_CIPHER_LIST"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_PROXY_SSL_CIPHER_LIST"
---

# CURLOPT\_PROXY\_SSL\_CIPHER\_LIST(3)

ciphers to use for HTTPS proxy

## NAME

CURLOPT\_PROXY\_SSL\_CIPHER\_LIST - ciphers to use for HTTPS proxy

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSL_CIPHER_LIST,
                          char *list);
```

## DESCRIPTION

Pass a char pointer, pointing to a null-terminated string holding the list of cipher suites to use for the TLS 1.2 (1.1, 1.0) connection to the HTTPS proxy. The list must be syntactically correct, it consists of one or more cipher suite strings separated by colons.

For setting TLS 1.3 ciphers see *[CURLOPT\_PROXY\_TLS13\_CIPHERS(3)](/CURLOPT_PROXY_TLS13_CIPHERS/3.md)*.

A valid example of a cipher list is:

```
"ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:"
"ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305"
```

For Schannel, you can use this option to set algorithms but not specific cipher suites. Refer to the ciphers lists document for algorithms.

Find more details about cipher lists on this URL:

 https://curl.se/docs/ssl-ciphers.html

The application does not have to keep the string around after setting this option.

Using this option multiple times makes the last set string override the previous ones. Set it to NULL to disable its use again.

## DEFAULT

NULL, use internal built-in list.

## 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, Rustls, Schannel, mbedTLS and wolfSSL

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost");
    curl_easy_setopt(curl, CURLOPT_PROXY_SSL_CIPHER_LIST,
                     "ECDHE-ECDSA-CHACHA20-POLY1305:"
                     "ECDHE-RSA-CHACHA20-POLY1305");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
```

## HISTORY

OpenSSL support added in 7.52.0. wolfSSL, Schannel support added in 7.87.0 mbedTLS support added in 8.8.0. Rustls support added in 8.10.0.

Since curl 8.10.0 returns CURLE\_NOT\_BUILT\_IN when not supported.

## AVAILABILITY

Added in curl 7.52.0

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_PROXY\_SSLVERSION**(3)](/CURLOPT_PROXY_SSLVERSION/3.md), [**CURLOPT\_PROXY\_TLS13\_CIPHERS**(3)](/CURLOPT_PROXY_TLS13_CIPHERS/3.md), [**CURLOPT\_SSLVERSION**(3)](/CURLOPT_SSLVERSION/3.md), [**CURLOPT\_SSL\_CIPHER\_LIST**(3)](/CURLOPT_SSL_CIPHER_LIST/3.md), [**CURLOPT\_TLS13\_CIPHERS**(3)](/CURLOPT_TLS13_CIPHERS/3.md)