EVP_chacha20(pdf.php) - phpMan

EVP_CHACHA20(3)                     OpenSSL                    EVP_CHACHA20(3)
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 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.
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 2017-2019 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>;.
1.1.1k                            2021-03-25                   EVP_CHACHA20(3)