EVP_AES_128_GCM(3ossl)

📦
version 3.5.9 · 8 versions
, in fedora 43, fedora 44

💖 NAME 💖

okay so bestie, this entire page is one big found family: the EVP AES ciphers. Every single one of these functions gives you a cipher back, and honestly? iconic lineup. Here's the full guest list, no one left out, periodt:

  • CBC: EVP_aes_128_cbc, EVP_aes_192_cbc, EVP_aes_256_cbc
  • CFB (128-bit shift): EVP_aes_128_cfb, EVP_aes_192_cfb, EVP_aes_256_cfb
  • CFB with 1-bit shift: EVP_aes_128_cfb1, EVP_aes_192_cfb1, EVP_aes_256_cfb1
  • CFB with 8-bit shift: EVP_aes_128_cfb8, EVP_aes_192_cfb8, EVP_aes_256_cfb8
  • CFB with 128-bit shift, the explicit one: EVP_aes_128_cfb128, EVP_aes_192_cfb128, EVP_aes_256_cfb128
  • CTR: EVP_aes_128_ctr, EVP_aes_192_ctr, EVP_aes_256_ctr
  • ECB: EVP_aes_128_ecb, EVP_aes_192_ecb, EVP_aes_256_ecb
  • OFB: EVP_aes_128_ofb, EVP_aes_192_ofb, EVP_aes_256_ofb
  • CBC + HMAC-SHA1: EVP_aes_128_cbc_hmac_sha1, EVP_aes_256_cbc_hmac_sha1
  • CBC + HMAC-SHA256: EVP_aes_128_cbc_hmac_sha256, EVP_aes_256_cbc_hmac_sha256
  • CCM: EVP_aes_128_ccm, EVP_aes_192_ccm, EVP_aes_256_ccm
  • GCM: EVP_aes_128_gcm, EVP_aes_192_gcm, EVP_aes_256_gcm
  • OCB: EVP_aes_128_ocb, EVP_aes_192_ocb, EVP_aes_256_ocb
  • Key wrap: EVP_aes_128_wrap, EVP_aes_192_wrap, EVP_aes_256_wrap
  • Key wrap with padding: EVP_aes_128_wrap_pad, EVP_aes_192_wrap_pad, EVP_aes_256_wrap_pad
  • XTS: EVP_aes_128_xts, EVP_aes_256_xts

…and collectively they're the EVP AES cipher. That's the whole vibe. 🦋

This page lives in the 3ossl manual, part of the OpenSSL docs, just so you know where you are. 💅

✨ SYNOPSIS ✨

#include <openssl/evp.h>

const EVP_CIPHER *EVP_ciphername(void)

So EVP_ciphername is a lil placeholder, okay? It stands in for any of the cipher functions described on this page — swap it out for something real like EVP_aes_128_cbc and you're off to the races. 🏁

🌸 DESCRIPTION 🌸

It's the AES encryption algorithm, but for EVP. That's the whole thesis. Now let's meet the families one by one.

💫 CBC, CFB, CTR, ECB, OFB — the classics

EVP_aes_128_cbc(), EVP_aes_192_cbc(), EVP_aes_256_cbc(), EVP_aes_128_cfb(), EVP_aes_192_cfb(), EVP_aes_256_cfb(), EVP_aes_128_cfb1(), EVP_aes_192_cfb1(), EVP_aes_256_cfb1(), EVP_aes_128_cfb8(), EVP_aes_192_cfb8(), EVP_aes_256_cfb8(), EVP_aes_128_cfb128(), EVP_aes_192_cfb128(), EVP_aes_256_cfb128(), EVP_aes_128_ctr(), EVP_aes_192_ctr(), EVP_aes_256_ctr(), EVP_aes_128_ecb(), EVP_aes_192_ecb(), EVP_aes_256_ecb(), EVP_aes_128_ofb(), EVP_aes_192_ofb(), EVP_aes_256_ofb()

These are AES for 128, 192 and 256 bit keys, across these modes: CBC, CFB with 128-bit shift, CFB with 1-bit shift, CFB with 8-bit shift, CTR, ECB, and OFB. Pick your fighter. 🥊

🔐 EVP_aes_128_cbc_hmac_sha1(), EVP_aes_256_cbc_hmac_sha1()

Authenticated encryption with AES in CBC mode, using SHA-1 as the HMAC, with keys of 128 and 256 bits length respectively. The authentication tag is 160 bits long.

🚨 WARNING bestie, for real: this is not intended for usage outside of TLS and it requires calling some undocumented ctrl functions. These ciphers do not conform to the EVP AEAD interface. Like, do not invite this one to the party unless you're literally in TLS. 😭

🔐 EVP_aes_128_cbc_hmac_sha256(), EVP_aes_256_cbc_hmac_sha256()

Same energy but glowier: authenticated encryption with AES in CBC mode using SHA256 (SHA-2, 256-bits) as the HMAC, with keys of 128 and 256 bits length respectively. The authentication tag is 256 bits long.

🚨 WARNING again, seriously: not intended for usage outside of TLS, requires some undocumented ctrl functions, and these ciphers do not conform to the EVP AEAD interface. Respect the boundary. 💀

🌈 EVP_aes_128_ccm(), EVP_aes_192_ccm(), EVP_aes_256_ccm(), EVP_aes_128_gcm(), EVP_aes_192_gcm(), EVP_aes_256_gcm(), EVP_aes_128_ocb(), EVP_aes_192_ocb(), EVP_aes_256_ocb()

AES for 128, 192 and 256 bit keys in CBC-MAC Mode (CCM), Galois Counter Mode (GCM) and OCB Mode respectively. These ciphers need additional control operations to function correctly — check out the "AEAD INTERFACE" in EVP_EncryptInit(3) for the details, iykyk. 🔥

🎀 EVP_aes_128_wrap(), EVP_aes_192_wrap(), EVP_aes_256_wrap(), EVP_aes_128_wrap_pad(), EVP_aes_192_wrap_pad(), EVP_aes_256_wrap_pad()

AES key wrap with 128, 192 and 256 bit keys, as according to RFC 3394 section 2.2.1 ("wrap") and RFC 5649 section 4.1 ("wrap with padding") respectively. Wrapping keys in lil presents, so cute. 🎁

👑 EVP_aes_128_xts(), EVP_aes_256_xts()

AES XTS mode (XTS-AES) is standardized in IEEE Std. 1619-2007 and described in NIST SP 800-38E. The XTS (XEX-based tweaked-codebook mode with ciphertext stealing) mode was designed by Prof. Phillip Rogaway of University of California, Davis, intended for encrypting data on a storage device. Main character energy, honestly.

XTS-AES provides confidentiality but not authentication of data. It also requires a key of double-length for protection of a certain key size. In particular, XTS-AES-128 (EVP_aes_128_xts) takes input of a 256-bit key to achieve AES 128-bit security, and XTS-AES-256 (EVP_aes_256_xts) takes input of a 512-bit key to achieve AES 256-bit security. Double the key, same security level. That's the deal. 💅

The XTS implementation in OpenSSL does not support streaming. That is, there must only be one EVP_EncryptUpdate(3) call per EVP_EncryptInit_ex(3) call (and similarly with the "Decrypt" functions). No sneaking extra updates in, she will not allow it. 🙈

The iv parameter to EVP_EncryptInit_ex(3) or EVP_DecryptInit_ex(3) is the XTS "tweak" value.

🫶 NOTES 🫶

Bestie, heads up: developers should be aware of the negative performance implications of calling these functions multiple times, and should consider using EVP_CIPHER_fetch(3) with EVP_CIPHER-AES(7) instead. See "Performance" in crypto(7) for further information. Future you will be grateful, fr fr. ⭐

💜 RETURN VALUES 💜

These functions return an EVP_CIPHER structure that contains the implementation of the symmetric cipher. Peep EVP_CIPHER_meth_new(3) for the deets on the EVP_CIPHER structure itself. ✨

🦋 SEE ALSO 🦋

Copyright 2017-2025 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 was OpenSSL 3.5.9, dated 2026-09-29, and the manual page itself is EVP_AES_128_GCM(3ossl). Go encrypt something, slay, drink water. 💖🌸🦋

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