EVP_SEED_CBC(3ossl)

💜 EVP_SEED_CBC — the SEED cipher page, bestie edition

okay so this is a page from the OpenSSL manual, section 3ossl — and it's all about the SEED cipher and the little family of functions that hand you one 💅

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✨ NAME ✨

EVP_seed_cbc, EVP_seed_cfb, EVP_seed_cfb128, EVP_seed_ecb, EVP_seed_ofb — literally the EVP SEED cipher, that's the whole vibe 🎀

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🌸 SYNOPSIS 🌸

#include <openssl/evp.h>

const EVP_CIPHER *EVP_seed_cbc(void);
const EVP_CIPHER *EVP_seed_cfb(void);
const EVP_CIPHER *EVP_seed_cfb128(void);
const EVP_CIPHER *EVP_seed_ecb(void);
const EVP_CIPHER *EVP_seed_ofb(void);

like, five functions, all returning const EVP_CIPHER *, no args, no drama 🫶

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🦋 DESCRIPTION 🦋

So the SEED encryption algorithm, right? This is it, but for EVP — the OpenSSL EVP layer ✨

Every single mode down below uses a key length of 128 bits and acts on blocks of 128-bits. no cap, that's the specs, love that for them 💖

🎀 the functions themselves

• EVP_seed_cbc(), EVP_seed_cfb(), EVP_seed_cfb128(), EVP_seed_ecb(), EVP_seed_ofb() — these give you the SEED encryption algorithm in CBC, CFB, ECB and OFB modes respectively. yes, that's four mode names for five functions — EVP_seed_cfb() and EVP_seed_cfb128() are both CFB, iykyk 👑

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🔥 NOTES 🔥

okay bestie, listen up, this part matters 👀

Developers should be aware of the negative performance implications of calling these functions multiple times — like, calling them over and over is not it. Instead, consider using EVP_CIPHER_fetch(3) with EVP_CIPHER-SEED(7). See "Performance" in crypto(7) for further information 🧚

fr fr, don't just spam these calls in a loop. fetch it once, live your life 💅

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⭐ RETURN VALUES ⭐

These functions return an EVP_CIPHER structure that contains the implementation of the symmetric cipher. Wanna know what's actually inside that structure? See EVP_CIPHER_meth_new(3) for details of the EVP_CIPHER structure 👑

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🌈 SEE ALSO 🌈

evp(7), EVP_EncryptInit(3), EVP_CIPHER_meth_new(3)

go read those too, they're giving main character energy 📚✨

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👑 COPYRIGHT 👑

Copyright 2017-2023 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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aaaand that's the whole page, bestie 🍓 sign-off time: this one's from OpenSSL 3.5.6, dated 2026-04-07, and the page itself is EVP_SEED_CBC(3ossl) — slay, go encrypt something responsibly 💖✨🎀