EVP_CIPHER-SM4(7ossl)

📦 version 3.5.0, in opensuse-leap 16.0

💅 EVP_CIPHER-SM4

okay bestie, welcome to the glow-up era of symmetric encryption ✨ this little page lives in the OpenSSL 7ossl manual fam, and it's all about the SM4 EVP_CIPHER implementations — like, the whole squad of them 🎀

🌸 NAME

EVP_CIPHER-SM4 — the SM4 EVP_CIPHER implementations, periodt 💅

✨ DESCRIPTION

So basically: this is support for SM4 symmetric encryption using the EVP_CIPHER API 🦋 that's it, that's the vibe. no cap.

🔥 Algorithm Names

these beauties are all available in the default provider — like, they're already in the group chat, no invite needed 👑

  • "SM4-CBC:SM4"
  • "SM4-ECB"
  • "SM4-CTR"
  • "SM4-OFB" or "SM4-OFB128"
  • "SM4-CFB" or "SM4-CFB128"
  • "SM4-GCM"
  • "SM4-CCM"
  • "SM4-XTS"

🎀 Parameters

this implementation supports the parameters described in "PARAMETERS" in EVP_EncryptInit(3) — go read that one, it's giving essential lore 📖✨

💀 NOTES

okay so this is the part where you actually listen, bestie 🙈

The SM4-XTS implementation does allow streaming to be performed, but each EVP_EncryptUpdate(3) or EVP_DecryptUpdate(3) call requires each input to be a multiple of the blocksize. like, every single one. no exceptions, fr fr.

Only the final EVP_EncryptUpdate() or EVP_DecryptUpdate() call can optionally have an input that is not a multiple of the blocksize — but that input still has to be larger than one block. In that case, ciphertext stealing (CTS) is used to fill the block 🫶✨

lowkey important: get the block sizes wrong on a non-final call and the vibe check fails. respect the blocksize 👑

🌈 SEE ALSO

Copyright 2021 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 page, bestie 🧚💜 this one's from OpenSSL version 3.5.0, dated 2026-09-25, filed under EVP_CIPHER-SM4(7ossl) — slay, go encrypt something cute 💅🌸

📦 where this page comes from