EVP_CIPHER-AES(7ossl)

📦
version 3.5.9 · 8 versions
, in alpine 3.23, alpine 3.24

💖 NAME 💖

EVP_CIPHER-AES — the whole AES EVP_CIPHER implementation situation, straight from the OpenSSL manual (section 7ossl, iykyk). Bestie, this is your map to every AES cipher name you can pass around and what the spicy rules are. 🫶

✨ DESCRIPTION ✨

It's support for AES symmetric encryption using the EVP_CIPHER API. That's the whole vibe. 🔥

🎀 Algorithm Names 🎀

The following algorithms are available in the FIPS provider as well as the default provider:

  • "AES-128-CBC", "AES-192-CBC" and "AES-256-CBC"
  • "AES-128-CBC-CTS", "AES-192-CBC-CTS" and "AES-256-CBC-CTS"
  • "AES-128-CFB", "AES-192-CFB", "AES-256-CFB", "AES-128-CFB1", "AES-192-CFB1", "AES-256-CFB1", "AES-128-CFB8", "AES-192-CFB8" and "AES-256-CFB8"
  • "AES-128-CTR", "AES-192-CTR" and "AES-256-CTR"
  • "AES-128-ECB", "AES-192-ECB" and "AES-256-ECB"
  • "AES-192-OFB", "AES-128-OFB" and "AES-256-OFB" (yes, that's the order the manual gives them in, don't come for me 💀)
  • "AES-128-XTS" and "AES-256-XTS"
  • "AES-128-CCM", "AES-192-CCM" and "AES-256-CCM"
  • "AES-128-GCM", "AES-192-GCM" and "AES-256-GCM"
  • "AES-128-WRAP", "AES-192-WRAP", "AES-256-WRAP", "AES-128-WRAP-PAD", "AES-192-WRAP-PAD", "AES-256-WRAP-PAD", "AES-128-WRAP-INV", "AES-192-WRAP-INV", "AES-256-WRAP-INV", "AES-128-WRAP-PAD-INV", "AES-192-WRAP-PAD-INV" and "AES-256-WRAP-PAD-INV"
  • "AES-128-CBC-HMAC-SHA1", "AES-256-CBC-HMAC-SHA1", "AES-128-CBC-HMAC-SHA256" and "AES-256-CBC-HMAC-SHA256"

The following algorithms are available in the default provider, but not the FIPS provider:

  • "AES-128-OCB", "AES-192-OCB" and "AES-256-OCB"
  • "AES-128-SIV", "AES-192-SIV" and "AES-256-SIV"
  • "AES-128-GCM-SIV", "AES-192-GCM-SIV" and "AES-256-GCM-SIV"

🌸 Parameters 🌸

This implementation supports the parameters described in "PARAMETERS" in EVP_EncryptInit(3). For implementations in the OpenSSL FIPS provider, those include the gettable "fips-indicator" (OSSL_CIPHER_PARAM_FIPS_APPROVED_INDICATOR), which returns 1 if the operation is FIPS approved, or 0 otherwise. See "FIPS indicators" in fips_module(7) for more info. 👑

For AES-GCM encryption, an externally supplied IV makes the operation non-approved, so this indicator returns 0. See "PARAMETERS" in EVP_EncryptInit(3) for the related "iv-generated" parameter. And AES-GCM tag lengths are approved only when they are 4, 8, or 12 through 16 bytes. No cap, that's just the rule. 💅

💅 NOTES 💅

Okay so here's where the vibes get particular, bestie. Listen up. 🎧

  • The AES-SIV and AES-WRAP mode implementations do not support streaming. That means to obtain correct results there can be only one EVP_EncryptUpdate(3) or EVP_DecryptUpdate(3) call after the initialization of the context. One. Uno. Not two. 😭
  • When wrapping with AES-WRAP-PAD ciphers, the output buffer must be at least inl rounded up to the cipher block size (8 bytes) plus the block size. That is, the minimum output buffer size is ((inl + 7) / 8) * 8 + 8 bytes. Write that down fr fr. 🍓
  • The AES-XTS implementations 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. Only the final EVP_EncryptUpdate() or EVP_DecryptUpdate() call can optionally have an input that is not a multiple of the blocksize but is larger than one block. In that case ciphertext stealing (CTS) is used to fill the block. Iconic little trick, honestly. ✨

🦋 SEE ALSO 🦋

🔥 HISTORY 🔥

The GCM-SIV mode ciphers were added in OpenSSL version 3.2. Glow-up era. 🌈

Copyright 2021-2026 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 — straight from OpenSSL version 3.5.9, dated 2026-09-29. Slay, go forth and encrypt responsibly. 🧚💜

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