EVP_chacha20.3ssl man page

 #include <openssl/evp.h>

 const EVP_CIPHER *EVP_chacha20(void)
 const EVP_CIPHER *EVP_chacha20_poly1305(void)

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 32 bits consists of a counter in little-endian order followed by a 96 bit nonce. For example a nonce of:

000000000000000000000002

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.

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.

evp(7), EVP_EncryptInit(3), EVP_CIPHER_meth_new(3)

Copyright 2017-2019 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (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>.

EVP_EncryptInit.3ssl(3).

The man page EVP_chacha20_poly1305.3ssl(3) is an alias of EVP_chacha20.3ssl(3).