EVP_CIPHER-AES(7SSL)

📦
version 4.0.3 · 13 versions
, in ubuntu stonking

💖 EVP_CIPHER-AES — the aes glow-up, explained 💖

okay bestie, sit down, hydrate, because this is the EVP_CIPHER-AES(7SSL) page and it's literally the whole AES family reunion under the EVP_CIPHER API.

✨ NAME ✨

EVP_CIPHER-AES — the AES EVP_CIPHER implementations. that's it, that's the name, she's simple but she runs half the internet 💅

🌸 DESCRIPTION 🌸

Support for AES symmetric encryption using the EVP_CIPHER API. yes queen, symmetric, we love a shared-secret moment.

🦋 Algorithm Names 🦋

The following algorithms are available in the FIPS provider as well as the default provider — so both girlies ship them:

  • "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"
  • "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 — sorry babes, they didn't make the approved cut:

  • "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). iconic behavior.

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. like a vibe check but for compliance 💀 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. (yes, fr fr, your own IV = not approved behavior.) see "PARAMETERS" in EVP_EncryptInit(3) for the related "iv-generated" parameter.

AES-GCM tag lengths are approved only when they are 4, 8, or 12 through 16 bytes. those exact numbers, bestie, don't freestyle.

👑 NOTES 👑

listen up, this is the part where people get humbled:

  • 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. single. call. no cap 😭
  • 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. get your math right or she will simply not work 🫶

  • The AES-XTS implementations do 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. she's stealing but make it legal ✨

🌈 SEE ALSO 🌈

provider-cipher(7), OSSL_PROVIDER-FIPS(7), OSSL_PROVIDER-default(7) — go read those next, they're the supporting cast and they ate.

⭐ HISTORY ⭐

The GCM-SIV mode ciphers were added in OpenSSL version 3.2. glow-up acquired in 3.2, periodt.

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!! 💖✨ this one's from the OpenSSL 4.0.3 era, dated 2026-09-29 — stay encrypted, stay iconic, mwah 🎀🦋💅

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