EC_GFP_SIMPLE_METHOD(3SSL)

💖 EC_GFP_SIMPLE_METHOD(3SSL) 💖

okay bestie, welcome to the EC_GFp_simple_method page from the OpenSSL fam — manual section 3SSL, the elliptic curve method-gettin' zone 💅

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✨ NAME ✨

EC_GFp_simple_method, EC_GFp_mont_method, EC_GFp_nist_method, EC_GFp_nistp224_method, EC_GFp_nistp256_method, EC_GFp_nistp521_method, EC_GF2m_simple_method, EC_METHOD_get_field_type — literally just functions that hand you EC_METHOD objects 🎀

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✨ SYNOPSIS ✨

#include <openssl/ec.h>

so here's the tea: the following functions have been deprecated since OpenSSL 3.0 😭 and you can hide them entirely by defining OPENSSL_API_COMPAT with a suitable version value — peep openssl_user_macros(7) for that:

const EC_METHOD *EC_GFp_simple_method(void);
const EC_METHOD *EC_GFp_mont_method(void);
const EC_METHOD *EC_GFp_nist_method(void);
const EC_METHOD *EC_GFp_nistp224_method(void);
const EC_METHOD *EC_GFp_nistp256_method(void);
const EC_METHOD *EC_GFp_nistp521_method(void);

const EC_METHOD *EC_GF2m_simple_method(void);

int EC_METHOD_get_field_type(const EC_METHOD *meth);

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✨ DESCRIPTION ✨

so first thing, no cap: all the const EC_METHOD *EC_GF* functions were deprecated in OpenSSL 3.0, because EC_METHOD is no longer a public concept 🫠 it's giving "we moved on".

The Elliptic Curve library ships a bunch of different implementations through one single common interface. When you construct a curve using EC_GROUP_new (see EC_GROUP_new(3)) you gotta provide an implementation method. Every function on this page returns a const pointer to an EC_METHOD structure that you can pass straight to EC_GROUP_NEW. And bestie, it is important that you use the correct implementation type for the form of curve you selected — like, don't mix and match, it's not that kind of party 🌸

For F2^m curves there's literally only one implementation choice, i.e. EC_GF2_simple_method. One option, no drama, iconic.

For Fp curves, the lowest common denominator implementation is the EC_GFp_simple_method implementation. All the other ones are built on top of it — the blueprint, the mother, the main character 👑

• EC_GFp_mont_method builds on EC_GFp_simple_method but adds the use of montgomery multiplication (see BN_mod_mul_montgomery(3)) 🔥
• EC_GFp_nist_method offers an implementation optimised for use with NIST recommended curves (NIST curves are available through EC_GROUP_new_by_curve_name as described in EC_GROUP_new(3)) 💜

Then there's the little trio of speedy ones: EC_GFp_nistp224_method, EC_GFp_nistp256_method and EC_GFp_nistp521_method offer 64 bit optimised implementations for the NIST P224, P256 and P521 curves respectively. Note, however — and this is the important part — these implementations are not available on all platforms 🙈 so vibe check your target first.

EC_METHOD_get_field_type() was deprecated in OpenSSL 3.0 too. Applications should use EC_GROUP_get_field_type() as a replacement (see EC_GROUP_copy(3)) — glow up, bestie ✨

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✨ RETURN VALUES ✨

All the EC_GFp* functions and EC_GF2m_simple_method always return a const pointer to an EC_METHOD structure. Always. No cap. 💯

EC_METHOD_get_field_type returns an integer that identifies the type of field the EC_METHOD structure supports 🔢

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✨ SEE ALSO ✨

crypto(7), EC_GROUP_new(3), EC_GROUP_copy(3), EC_POINT_new(3), EC_POINT_add(3), EC_KEY_new(3), d2i_ECPKParameters(3), BN_mod_mul_montgomery(3) — go read these, they're the friend group 🦋

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✨ HISTORY ✨

EC_GFp_simple_method(), EC_GFp_mont_method(void), EC_GFp_nist_method(), EC_GFp_nistp224_method(), EC_GFp_nistp256_method(), EC_GFp_nistp521_method(), EC_GF2m_simple_method(), and EC_METHOD_get_field_type() were all deprecated in OpenSSL 3.0. the whole squad, gone together 😭 periodt.

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✨ COPYRIGHT ✨

Copyright 2013-2020 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>.

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⚠️ quick reminder bestie: deprecated means deprecated — it still exists, but the library is side-eyeing you and you should be using the newer replacements wherever this page says so. don't build new stuff on it, fr fr.

okay that's the whole page, mwah 💋 this was OpenSSL 4.0.3, dated 2026-09-29, and it's been a pleasure serving you the EC_GFP_SIMPLE_METHOD(3SSL) tea 🍓💜🫶