| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 1 | =pod |
| 2 | |
| 3 | =head1 NAME |
| 4 | |
| 5 | EVP_chacha20, |
| 6 | EVP_chacha20_poly1305 |
| 7 | - EVP ChaCha20 stream cipher |
| 8 | |
| 9 | =head1 SYNOPSIS |
| 10 | |
| 11 | #include <openssl/evp.h> |
| 12 | |
| 13 | const EVP_CIPHER *EVP_chacha20(void) |
| 14 | const EVP_CIPHER *EVP_chacha20_poly1305(void) |
| 15 | |
| 16 | =head1 DESCRIPTION |
| 17 | |
| 18 | The ChaCha20 stream cipher for EVP. |
| 19 | |
| 20 | =over 4 |
| 21 | |
| 22 | =item EVP_chacha20() |
| 23 | |
| 24 | The ChaCha20 stream cipher. The key length is 256 bits, the IV is 128 bits long. |
| 25 | The first 32 bits consists of a counter in little-endian order followed by a 96 |
| 26 | bit nonce. For example a nonce of: |
| 27 | |
| 28 | 000000000000000000000002 |
| 29 | |
| 30 | With an initial counter of 42 (2a in hex) would be expressed as: |
| 31 | |
| 32 | 2a000000000000000000000000000002 |
| 33 | |
| 34 | =item EVP_chacha20_poly1305() |
| 35 | |
| 36 | Authenticated encryption with ChaCha20-Poly1305. Like EVP_chacha20(), the key |
| 37 | is 256 bits and the IV is 96 bits. This supports additional authenticated data |
| 38 | (AAD) and produces a 128-bit authentication tag. See the |
| 39 | L<EVP_EncryptInit(3)/AEAD Interface> section for more information. |
| 40 | |
| 41 | =back |
| 42 | |
| 43 | =head1 RETURN VALUES |
| 44 | |
| 45 | These functions return an B<EVP_CIPHER> structure that contains the |
| 46 | implementation of the symmetric cipher. See L<EVP_CIPHER_meth_new(3)> for |
| 47 | details of the B<EVP_CIPHER> structure. |
| 48 | |
| 49 | =head1 SEE ALSO |
| 50 | |
| 51 | L<evp(7)>, |
| 52 | L<EVP_EncryptInit(3)>, |
| 53 | L<EVP_CIPHER_meth_new(3)> |
| 54 | |
| 55 | =head1 COPYRIGHT |
| 56 | |
| 57 | Copyright 2017-2019 The OpenSSL Project Authors. All Rights Reserved. |
| 58 | |
| 59 | Licensed under the OpenSSL license (the "License"). You may not use |
| 60 | this file except in compliance with the License. You can obtain a copy |
| 61 | in the file LICENSE in the source distribution or at |
| 62 | L<https://www.openssl.org/source/license.html>. |
| 63 | |
| 64 | =cut |
| 65 | |