EVP_KEYMGMT(3ossl)

📦 version 15.1, in freebsd 15.1

🌸 NAME 🌸

Okay bestie, welcome to EVP_KEYMGMT(3ossl) — an OpenSSL manual page, and it's giving key management main character energy ✨

This page is the whole squad for EVP key management routines: EVP_KEYMGMT, EVP_KEYMGMT_fetch, EVP_KEYMGMT_up_ref, EVP_KEYMGMT_free, EVP_KEYMGMT_get0_provider, EVP_KEYMGMT_is_a, EVP_KEYMGMT_get0_description, EVP_KEYMGMT_get0_name, EVP_KEYMGMT_do_all_provided, EVP_KEYMGMT_names_do_all, EVP_KEYMGMT_gettable_params, EVP_KEYMGMT_settable_params, EVP_KEYMGMT_gen_gettable_params, and EVP_KEYMGMT_gen_settable_params. Periodt. 💅

✨ SYNOPSIS ✨

No cap, here's the include and the full signature lineup, verbatim — copy it exactly, bestie:

#include <openssl/evp.h>

typedef struct evp_keymgmt_st EVP_KEYMGMT;

EVP_KEYMGMT *EVP_KEYMGMT_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
                               const char *properties);
int EVP_KEYMGMT_up_ref(EVP_KEYMGMT *keymgmt);
void EVP_KEYMGMT_free(EVP_KEYMGMT *keymgmt);
const OSSL_PROVIDER *EVP_KEYMGMT_get0_provider(const EVP_KEYMGMT *keymgmt);
int EVP_KEYMGMT_is_a(const EVP_KEYMGMT *keymgmt, const char *name);
const char *EVP_KEYMGMT_get0_name(const EVP_KEYMGMT *keymgmt);
const char *EVP_KEYMGMT_get0_description(const EVP_KEYMGMT *keymgmt);

void EVP_KEYMGMT_do_all_provided(OSSL_LIB_CTX *libctx,
                                 void (*fn)(EVP_KEYMGMT *keymgmt, void *arg),
                                 void *arg);
int EVP_KEYMGMT_names_do_all(const EVP_KEYMGMT *keymgmt,
                             void (*fn)(const char *name, void *data),
                             void *data);
const OSSL_PARAM *EVP_KEYMGMT_gettable_params(const EVP_KEYMGMT *keymgmt);
const OSSL_PARAM *EVP_KEYMGMT_settable_params(const EVP_KEYMGMT *keymgmt);
const OSSL_PARAM *EVP_KEYMGMT_gen_settable_params(const EVP_KEYMGMT *keymgmt);
const OSSL_PARAM *EVP_KEYMGMT_gen_gettable_params(const EVP_KEYMGMT *keymgmt);

💖 DESCRIPTION 💖

Okay so, EVP_KEYMGMT is a method object that represents key management implementations for different cryptographic algorithms. It's lowkey a big deal: this method object provides functionality to have providers import key material from the outside, as well as export key material to the outside. Most of the functionality can only be used internally and has no public interface, this object is simply passed into other functions when needed. iykyk 🫶

Here's the function-by-function vibe check, with all the facts intact:

EVP_KEYMGMT_fetch() — looks for an algorithm within the provider that has been loaded into the OSSL_LIB_CTX given by ctx, having the name given by algorithm and the properties given by properties. Obsessed with a targeted search. 🔍
EVP_KEYMGMT_up_ref() — increments the reference count for the given EVP_KEYMGMT keymgmt. Ref count go brrr. ⬆️
EVP_KEYMGMT_free() — decrements the reference count for the given EVP_KEYMGMT keymgmt, and when the count reaches zero, frees it. If the argument is NULL, nothing is done. Polite and conditional. 🎀
EVP_KEYMGMT_get0_provider() — returns the provider that has this particular implementation. Provider reveal. 👑
EVP_KEYMGMT_is_a() — checks if keymgmt is an implementation of an algorithm that's identifiable with name. Identity check, slay. 🪞
EVP_KEYMGMT_get0_name() — returns the algorithm name from the provided implementation for the given keymgmt. Note that the keymgmt may have multiple synonyms associated with it. In this case the first name from the algorithm definition is returned. Ownership of the returned string is retained by the keymgmt object and should not be freed by the caller. Do not free it, bestie — that's not your string. 😭
EVP_KEYMGMT_names_do_all() — traverses all names for the keymgmt, and calls fn with each name and data. Name tour, no cap. 🚌
EVP_KEYMGMT_get0_description() — returns a description of the keymgmt, meant for display and human consumption. The description is at the discretion of the keymgmt implementation. Human-readable and mysterious. 🙈
EVP_KEYMGMT_do_all_provided() — traverses all key keymgmt implementations by all activated providers in the library context libctx, and for each of the implementations, calls fn with the implementation method and data as arguments. Whole-provider sweep, iconic. 🌈
EVP_KEYMGMT_gettable_params() and EVP_KEYMGMT_settable_params() — return a constant OSSL_PARAM(3) array that describes the names and types of key parameters that can be retrieved or set. EVP_KEYMGMT_gettable_params() is used by EVP_PKEY_gettable_params(3). Params? Described. Periodt. 📋
EVP_KEYMGMT_gen_gettable_params() and EVP_KEYMGMT_gen_settable_params() — return a constant OSSL_PARAM(3) array that describes the names and types of key generation parameters that can be retrieved or set via EVP_PKEY_CTX_get_params(3) or EVP_PKEY_CTX_set_params(3) respectively. Generation params, get and set, fr fr. ⚙️

🧠 NOTES 🧠

EVP_KEYMGMT_fetch() may be called implicitly by other fetching functions, using the same library context and properties. Any other API that uses keys will typically do this. Not me finding out it happens behind the scenes. 💀

🎀 RETURN VALUES 🎀

EVP_KEYMGMT_fetch() returns a pointer to the key management implementation represented by an EVP_KEYMGMT object, or NULL on error. Pointer or nope.
EVP_KEYMGMT_up_ref() returns 1 on success, or 0 on error. One for yes, zero for oh no.
EVP_KEYMGMT_names_do_all() returns 1 if the callback was called for all names. A return value of 0 means that the callback was not called for any names. All names or no names, no in-between vibes.
EVP_KEYMGMT_free() doesn't return any value. It's void, bestie. No return, just release.
EVP_KEYMGMT_get0_provider() returns a pointer to a provider object, or NULL on error. Provider pointer, or NULL energy.
EVP_KEYMGMT_is_a() returns 1 of keymgmt was identifiable, otherwise 0. Identity confirmed or denied.
EVP_KEYMGMT_get0_name() returns the algorithm name, or NULL on error. Name drop or NULL drop.
EVP_KEYMGMT_get0_description() returns a pointer to a description, or NULL if there isn't one. Description maybe, NULL maybe.
EVP_KEYMGMT_gettable_params(), EVP_KEYMGMT_settable_params(), EVP_KEYMGMT_gen_gettable_params() and EVP_KEYMGMT_gen_settable_params() return a constant OSSL_PARAM(3) array or NULL on error. Param array or NULL, that's the whole story.

🦋 SEE ALSO 🦋

EVP_MD_fetch(3)
OSSL_LIB_CTX(3)

Go read those too, bestie — cross-references are self-care. 🫶

⭐ HISTORY ⭐

The function EVP_KEYMGMT_gen_gettable_params() was added in OpenSSL 3.4.0. All other functions described here were added in OpenSSL 3.0. History check: passed. ✅

👑 COPYRIGHT 👑

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>.

Legal text stays legal text, but make it cute: respect the License, bestie. 💜

This iconic page is serving OpenSSL 3.5.6, dated 2026-04-07, and its manual tag is EVP_KEYMGMT(3ossl) — bye bestie, go manage those keys 💅✨

📦 where this page comes from

freebsd 15.1: base 15.1
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on 2026-11-04: a language model's rewrite of the original, under its terms