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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>.

1.1.1v                            2023-08-01                   EVP_CHACHA20(3)