| =pod |
| |
| =head1 NAME |
| |
| EVP_chacha20, |
| EVP_chacha20_poly1305 |
| - EVP ChaCha20 stream cipher |
| |
| =head1 SYNOPSIS |
| |
| #include <openssl/evp.h> |
| |
| const EVP_CIPHER *EVP_chacha20(void); |
| const EVP_CIPHER *EVP_chacha20_poly1305(void); |
| |
| =head1 DESCRIPTION |
| |
| The ChaCha20 stream cipher for EVP. |
| |
| =over 4 |
| |
| =item 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 |
| |
| =item 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 |
| L<EVP_EncryptInit(3)/AEAD Interface> section for more information. |
| |
| =back |
| |
| =head1 RETURN VALUES |
| |
| These functions return an B<EVP_CIPHER> structure that contains the |
| implementation of the symmetric cipher. See L<EVP_CIPHER_meth_new(3)> for |
| details of the B<EVP_CIPHER> structure. |
| |
| =head1 SEE ALSO |
| |
| L<evp(7)>, |
| L<EVP_EncryptInit(3)>, |
| L<EVP_CIPHER_meth_new(3)> |
| |
| =head1 COPYRIGHT |
| |
| Copyright 2017-2020 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 |
| L<https://www.openssl.org/source/license.html>. |
| |
| =cut |
| |
