EVP_CHACHA20
Section: OpenSSL (3SSL)
Updated: 2024-03-03
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NAME
EVP_chacha20,
EVP_chacha20_poly1305
- EVP ChaCha20 stream cipher
SYNOPSIS
#include <openssl/evp.h>
const EVP_CIPHER *EVP_chacha20(void);
const EVP_CIPHER *EVP_chacha20_poly1305(void);
DESCRIPTION
The ChaCha20 stream cipher for EVP.
- EVP_chacha20()
-
The ChaCha20 stream cipher. The key length is 256 bits, the IV is 128 bits long.
The first 64 bits consists of a counter in little-endian order followed by a 64
bit nonce. For example a nonce of:
0000000000000002
With an initial counter of 42 (2a in hex) would be expressed as:
2a000000000000000000000000000002
- EVP_chacha20_poly1305()
-
Authenticated encryption with ChaCha20-Poly1305. Like EVP_chacha20(), the key
is 256 bits and the IV is 96 bits. This supports additional authenticated data
(AAD) and produces a 128-bit authentication tag. See the
``AEAD Interface'' in EVP_EncryptInit(3) section for more information.
NOTES
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-CHACHA(7) instead.
See ``Performance'' in crypto(7) for further information.
RFC 7539 <https://www.rfc-editor.org/rfc/rfc7539.html#section-2.4>
uses a 32 bit counter and a 96 bit nonce for the IV.
RETURN VALUES
These functions return an EVP_CIPHER structure that contains the
implementation of the symmetric cipher. See EVP_CIPHER_meth_new(3) for
details of the EVP_CIPHER structure.
SEE ALSO
evp(7),
EVP_EncryptInit(3),
EVP_CIPHER_meth_new(3)
COPYRIGHT
Copyright 2017-2023 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>.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- NOTES
-
- RETURN VALUES
-
- SEE ALSO
-
- COPYRIGHT
-
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