EC_KEY_GET_ENC_FLAGS(3ossl)

💖 EC_KEY_GET_ENC_FLAGS 💖

okay bestie, gather round, because we're diving into 3ossl — that's the OpenSSL manual section, and this little page is all about getting and setting the encoding flags for EC_KEY structures. no cap, it's shorter than you think but every byte matters. 🎀

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✨ NAME ✨

EC_KEY_get_enc_flags, EC_KEY_set_enc_flags — get and set flags for encoding EC_KEY structures. the way that's literally the whole job description. 💅

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🌸 SYNOPSIS 🌸

#include <openssl/ec.h>

unsigned int EC_KEY_get_enc_flags(const EC_KEY *key);
void EC_KEY_set_enc_flags(EC_KEY *eckey, unsigned int flags);

two functions, one header, zero drama. EC_KEY_get_enc_flags() takes a const EC_KEY *key, and EC_KEY_set_enc_flags() takes a mutable EC_KEY *eckey plus your unsigned int flags. 🦋

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🧚 DESCRIPTION 🧚

so here's the tea. ☕ the format of the external representation of the public key that gets written by i2d_ECPrivateKey() — like, whether it's stored in a compressed form or not — is described by the point_conversion_form. if you want the full rundown on point_conversion_form, go peek at EC_GROUP_copy(3). it's giving "read the prequel, bestie". 📚

now, when you're reading a private key that was encoded without an associated public key — for example, if EC_PKEY_NO_PUBKEY was used, see below — then d2i_ECPrivateKey() is a whole angel and generates the missing public key automatically. 🫶 iconic behaviour.

but 💀 private keys encoded without parameters (for example, if EC_PKEY_NO_PARAMETERS was used — again, see below) cannot be loaded using d2i_ECPrivateKey(). that's it, that's the boundary. no parameters, no entry. periodt.

okay so the main characters: EC_KEY_get_enc_flags() and EC_KEY_set_enc_flags() get and set the value of the encoding flags for the key. there are two encoding flags currently defined:

• EC_PKEY_NO_PARAMETERS
• EC_PKEY_NO_PUBKEY

these flags define the behaviour of how the key is converted into ASN1 in a call to i2d_ECPrivateKey(). let's break it down:

• if EC_PKEY_NO_PARAMETERS is set, then the public parameters for the curve are not encoded along with the private key.
• if EC_PKEY_NO_PUBKEY is set, then the public key is not encoded along with the private key.

that's the whole vibe check. small flags, big consequences. 🔥

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⭐ RETURN VALUES ⭐

EC_KEY_get_enc_flags() returns the value of the current encoding flags for the EC_KEY. that's the one. 👑

not me noticing EC_KEY_set_enc_flags() is declared void up there, so there's literally nothing for it to return. she sets and she leaves. 🚪💨

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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_GFp_simple_method(3)
• d2i_ECPKParameters(3)
• d2i_ECPrivateKey(3)

iykyk, the whole EC cinematic universe is right there. go read them, bestie, they're all connected. 🦋✨

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💜 COPYRIGHT 💜

Copyright 2015-2017 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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and that's the whole page, babe 🎀 this was EC_KEY_GET_ENC_FLAGS(3ossl) from OpenSSL 3.5.9, dated 2026-09-29 — main character energy from start to finish, mwah 💋💅