SSL_GET_CIPHERS(3ossl)

📦 version 3.5.0, in opensuse-leap 16.0

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💅 SSL_GET_CIPHERS(3ossl) 💅

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Okay so bestie, this is the OpenSSL manual page for the cipher-list functions. The manual name is SSL_GET_CIPHERS and it's from the 3ossl section, periodt.

✨ NAME ✨

SSL_get1_supported_ciphers, SSL_get_client_ciphers, SSL_get_ciphers, SSL_CTX_get_ciphers, SSL_bytes_to_cipher_list, SSL_get_cipher_list, SSL_get_shared_ciphers — get list of available SSL_CIPHERs. It's giving cipher inventory energy, fr fr.

🦋 SYNOPSIS 🦋

#include <openssl/ssl.h>

STACK_OF(SSL_CIPHER) *SSL_get_ciphers(const SSL *ssl);
STACK_OF(SSL_CIPHER) *SSL_CTX_get_ciphers(const SSL_CTX *ctx);
STACK_OF(SSL_CIPHER) *SSL_get1_supported_ciphers(SSL *s);
STACK_OF(SSL_CIPHER) *SSL_get_client_ciphers(const SSL *ssl);
int SSL_bytes_to_cipher_list(SSL *s, const unsigned char *bytes, size_t len,
                             int isv2format, STACK_OF(SSL_CIPHER) **sk,
                             STACK_OF(SSL_CIPHER) **scsvs);
const char *SSL_get_cipher_list(const SSL *ssl, int priority);
char *SSL_get_shared_ciphers(const SSL *s, char *buf, int size);

🌸 DESCRIPTION 🌸

Okay so let's break down this whole cipher situation, bestie. It's a lot but we're gonna slay it together 💖

  • SSL_get_ciphers() — returns the stack of available SSL_CIPHERs for ssl, sorted by preference. If ssl is NULL or no ciphers are available, NULL is returned. Like, no ciphers? No ciphers. Simple as that.
  • SSL_CTX_get_ciphers() — returns the stack of available SSL_CIPHERs for ctx. Iconic.
  • SSL_get1_supported_ciphers() — returns the stack of enabled SSL_CIPHERs for ssl as would be sent in a ClientHello (that is, sorted by preference). The list depends on settings like the cipher list, the supported protocol versions, the security level, and the enabled signature algorithms. SRP and PSK ciphers are only enabled if the appropriate callbacks or settings have been applied. The list of ciphers that would be sent in a ClientHello can differ from the list of ciphers that would be acceptable when acting as a server. For example, additional ciphers may be usable by a server if there is a gap in the list of supported protocols, and some ciphers may not be usable by a server if there is not a suitable certificate configured. If ssl is NULL or no ciphers are available, NULL is returned. Highkey a whole vibe check on your cipher choices.
  • SSL_get_client_ciphers() — returns the stack of available SSL_CIPHERs matching the list received from the client on ssl. If ssl is NULL, no ciphers are available, or ssl is not operating in server mode, NULL is returned. Server mode only, bestie 😭
  • SSL_bytes_to_cipher_list() — treats the supplied len octets in bytes as a wire-protocol cipher suite specification (in the three-octet-per-cipher SSLv2 wire format if isv2format is nonzero; otherwise the two-octet SSLv3/TLS wire format), and parses the cipher suites supported by the library into the returned stacks of SSL_CIPHER objects sk and Signalling Cipher-Suite Values scsvs. Unsupported cipher suites are ignored. Returns 1 on success and 0 on failure. Like, it's the decoder ring for your cipher bytes 🔥
  • SSL_get_cipher_list() — returns a pointer to the name of the SSL_CIPHER listed for ssl with priority. If ssl is NULL, no ciphers are available, or there are less ciphers than priority available, NULL is returned. So like, index-based cipher lookup, no cap.
  • SSL_get_shared_ciphers() — creates a colon separated and NUL terminated list of SSL_CIPHER names that are available in both the client and the server. buf is the buffer that should be populated with the list of names and size is the size of that buffer. A pointer to buf is returned on success or NULL on error. If the supplied buffer is not large enough to contain the complete list of names then a truncated list of names will be returned. Note that just because a ciphersuite is available (i.e. it is configured in the cipher list) and shared by both the client and the server it does not mean that it is enabled (see the description of SSL_get1_supported_ciphers() above). This function will return available shared ciphersuites whether or not they are enabled. This is a server side function only and must only be called after the completion of the initial handshake.
🫶 Bestie warning: SSL_get_shared_ciphers() is server-side ONLY and you gotta wait until the handshake is done. Don't come for me if you call it too early.

🎀 NOTES 🎀

The details of the ciphers obtained by SSL_get_ciphers(), SSL_CTX_get_ciphers(), SSL_get1_supported_ciphers() and SSL_get_client_ciphers() can be obtained using the SSL_CIPHER_get_name(3) family of functions. Slay that cross-reference.

Call SSL_get_cipher_list() with priority starting from 0 to obtain the sorted list of available ciphers, until NULL is returned. Like a for-loop but make it fashion.

💀 Note: SSL_get_ciphers(), SSL_CTX_get_ciphers() and SSL_get_client_ciphers() return a pointer to an internal cipher stack, which will be freed later on when the SSL or SSL_SESSION object is freed. Therefore, the calling code MUST NOT free the return value itself. Do NOT do it. I'm serious. Memory corruption is not the move.

The stack returned by SSL_get1_supported_ciphers() should be freed using sk_SSL_CIPHER_free(). You HAVE to free this one. Different rules, different stack.

The stacks returned by SSL_bytes_to_cipher_list() should be freed using sk_SSL_CIPHER_free(). Same energy — free it when you're done, bestie 💅

⭐ RETURN VALUES ⭐

See DESCRIPTION. That's it. That's the section. No extra lore, we already covered it, iykyk.

🌈 SEE ALSO 🌈

Go read those next, bestie. Your cipher knowledge is about to be unmatched.

Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.

And that's the whole manual page, bestie! Version 3.5.0, dated 2026-09-25. Go forth and slay those cipher stacks 💖✨🎀

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