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✏️ Editing: EVP_aes_128_ofb.3

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.\"
.IX Title "EVP_AES 3"
.TH EVP_AES 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
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, EVP_aes_128_cbc_hmac_sha1, EVP_aes_256_cbc_hmac_sha1, EVP_aes_128_cbc_hmac_sha256, EVP_aes_256_cbc_hmac_sha256, 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, 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, EVP_aes_128_xts, EVP_aes_256_xts \&\- EVP AES cipher
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/evp.h>
\&
\& const EVP_CIPHER *EVP_ciphername(void)
.Ve
.PP
\&\fIEVP_ciphername\fR is used a placeholder for any of the described cipher
functions, such as \fIEVP_aes_128_cbc\fR.
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The \s-1AES\s0 encryption algorithm for \s-1EVP.\s0
.IP "\fBEVP_aes_128_cbc()\fR, \fBEVP_aes_192_cbc()\fR, \fBEVP_aes_256_cbc()\fR, \fBEVP_aes_128_cfb()\fR, \fBEVP_aes_192_cfb()\fR, \fBEVP_aes_256_cfb()\fR, \fBEVP_aes_128_cfb1()\fR, \fBEVP_aes_192_cfb1()\fR, \fBEVP_aes_256_cfb1()\fR, \fBEVP_aes_128_cfb8()\fR, \fBEVP_aes_192_cfb8()\fR, \fBEVP_aes_256_cfb8()\fR, \fBEVP_aes_128_cfb128()\fR, \fBEVP_aes_192_cfb128()\fR, \fBEVP_aes_256_cfb128()\fR, \fBEVP_aes_128_ctr()\fR, \fBEVP_aes_192_ctr()\fR, \fBEVP_aes_256_ctr()\fR, \fBEVP_aes_128_ecb()\fR, \fBEVP_aes_192_ecb()\fR, \fBEVP_aes_256_ecb()\fR, \fBEVP_aes_128_ofb()\fR, \fBEVP_aes_192_ofb()\fR, \fBEVP_aes_256_ofb()\fR" 4
.IX Item "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()"
\&\s-1AES\s0 for 128, 192 and 256 bit keys in the following modes: \s-1CBC, CFB\s0 with 128\-bit
shift, \s-1CFB\s0 with 1\-bit shift, \s-1CFB\s0 with 8\-bit shift, \s-1CTR, ECB,\s0 and \s-1OFB.\s0
.IP "\fBEVP_aes_128_cbc_hmac_sha1()\fR, \fBEVP_aes_256_cbc_hmac_sha1()\fR" 4
.IX Item "EVP_aes_128_cbc_hmac_sha1(), EVP_aes_256_cbc_hmac_sha1()"
Authenticated encryption with \s-1AES\s0 in \s-1CBC\s0 mode using \s-1SHA\-1\s0 as \s-1HMAC,\s0 with keys of
128 and 256 bits length respectively. The authentication tag is 160 bits long.
.Sp
\&\s-1WARNING:\s0 this is not intended for usage outside of \s-1TLS\s0 and requires calling of
some undocumented ctrl functions. These ciphers do not conform to the \s-1EVP AEAD\s0
interface.
.IP "\fBEVP_aes_128_cbc_hmac_sha256()\fR, \fBEVP_aes_256_cbc_hmac_sha256()\fR" 4
.IX Item "EVP_aes_128_cbc_hmac_sha256(), EVP_aes_256_cbc_hmac_sha256()"
Authenticated encryption with \s-1AES\s0 in \s-1CBC\s0 mode using \s-1SHA256\s0 (\s-1SHA\-2,\s0 256\-bits) as
\&\s-1HMAC,\s0 with keys of 128 and 256 bits length respectively. The authentication tag
is 256 bits long.
.Sp
\&\s-1WARNING:\s0 this is not intended for usage outside of \s-1TLS\s0 and requires calling of
some undocumented ctrl functions. These ciphers do not conform to the \s-1EVP AEAD\s0
interface.
.IP "\fBEVP_aes_128_ccm()\fR, \fBEVP_aes_192_ccm()\fR, \fBEVP_aes_256_ccm()\fR, \fBEVP_aes_128_gcm()\fR, \fBEVP_aes_192_gcm()\fR, \fBEVP_aes_256_gcm()\fR, \fBEVP_aes_128_ocb()\fR, \fBEVP_aes_192_ocb()\fR, \fBEVP_aes_256_ocb()\fR" 4
.IX Item "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()"
\&\s-1AES\s0 for 128, 192 and 256 bit keys in CBC-MAC Mode (\s-1CCM\s0), Galois Counter Mode
(\s-1GCM\s0) and \s-1OCB\s0 Mode respectively. These ciphers require additional control
operations to function correctly, see the \*(L"\s-1AEAD\s0 Interface\*(R" in \fBEVP_EncryptInit\fR\|(3)
section for details.
.IP "\fBEVP_aes_128_wrap()\fR, \fBEVP_aes_192_wrap()\fR, \fBEVP_aes_256_wrap()\fR, \fBEVP_aes_128_wrap_pad()\fR, \fBEVP_aes_128_wrap()\fR, \fBEVP_aes_192_wrap()\fR, \fBEVP_aes_256_wrap()\fR, \fBEVP_aes_192_wrap_pad()\fR, \fBEVP_aes_128_wrap()\fR, \fBEVP_aes_192_wrap()\fR, \fBEVP_aes_256_wrap()\fR, \fBEVP_aes_256_wrap_pad()\fR" 4
.IX Item "EVP_aes_128_wrap(), EVP_aes_192_wrap(), EVP_aes_256_wrap(), EVP_aes_128_wrap_pad(), EVP_aes_128_wrap(), EVP_aes_192_wrap(), EVP_aes_256_wrap(), EVP_aes_192_wrap_pad(), EVP_aes_128_wrap(), EVP_aes_192_wrap(), EVP_aes_256_wrap(), EVP_aes_256_wrap_pad()"
\&\s-1AES\s0 key wrap with 128, 192 and 256 bit keys, as according to \s-1RFC 3394\s0 section
2.2.1 (\*(L"wrap\*(R") and \s-1RFC 5649\s0 section 4.1 (\*(L"wrap with padding\*(R") respectively.
.IP "\fBEVP_aes_128_xts()\fR, \fBEVP_aes_256_xts()\fR" 4
.IX Item "EVP_aes_128_xts(), EVP_aes_256_xts()"
\&\s-1AES XTS\s0 mode (XTS-AES) is standardized in \s-1IEEE\s0 Std. 1619\-2007 and described in \s-1NIST
SP 800\-38E.\s0 The \s-1XTS\s0 (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.
.Sp
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, \s-1XTS\-AES\-128\s0 (\fBEVP_aes_128_xts\fR) takes input of a 256\-bit key to
achieve \s-1AES\s0 128\-bit security, and \s-1XTS\-AES\-256\s0 (\fBEVP_aes_256_xts\fR) takes input
of a 512\-bit key to achieve \s-1AES\s0 256\-bit security.
.Sp
The \s-1XTS\s0 implementation in OpenSSL does not support streaming. That is there must
only be one \fBEVP_EncryptUpdate\fR\|(3) call per \fBEVP_EncryptInit_ex\fR\|(3) call (and
similarly with the \*(L"Decrypt\*(R" functions).
.Sp
The \fIiv\fR parameter to \fBEVP_EncryptInit_ex\fR\|(3) or \fBEVP_DecryptInit_ex\fR\|(3) is
the \s-1XTS\s0 \*(L"tweak\*(R" value.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
These functions return an \fB\s-1EVP_CIPHER\s0\fR structure that contains the
implementation of the symmetric cipher. See \fBEVP_CIPHER_meth_new\fR\|(3) for
details of the \fB\s-1EVP_CIPHER\s0\fR structure.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBevp\fR\|(7),
\&\fBEVP_EncryptInit\fR\|(3),
\&\fBEVP_CIPHER_meth_new\fR\|(3)
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2017\-2020 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the OpenSSL license (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.

MR SKB