ring/aead/
poly1305.rs

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1// Copyright 2015-2025 Brian Smith.
2//
3// Permission to use, copy, modify, and/or distribute this software for any
4// purpose with or without fee is hereby granted, provided that the above
5// copyright notice and this permission notice appear in all copies.
6//
7// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
14
15// TODO: enforce maximum input length.
16
17use super::{Tag, TAG_LEN};
18#[cfg(all(target_arch = "arm", target_endian = "little"))]
19use crate::cpu::GetFeature as _;
20use crate::{cpu, polyfill::slice::AsChunks};
21
22mod ffi_arm_neon;
23mod ffi_fallback;
24
25/// A Poly1305 key.
26pub(super) struct Key {
27    key_and_nonce: [u8; KEY_LEN],
28}
29
30pub(super) const BLOCK_LEN: usize = 16;
31pub(super) const KEY_LEN: usize = 2 * BLOCK_LEN;
32
33impl Key {
34    #[inline]
35    pub(super) fn new(key_and_nonce: [u8; KEY_LEN]) -> Self {
36        Self { key_and_nonce }
37    }
38}
39
40pub(super) enum Context {
41    #[cfg(all(target_arch = "arm", target_endian = "little"))]
42    ArmNeon(ffi_arm_neon::State),
43    Fallback(ffi_fallback::State),
44}
45
46impl Context {
47    #[inline]
48    pub(super) fn from_key(key: Key, cpu: cpu::Features) -> Self {
49        #[cfg(all(target_arch = "arm", target_endian = "little"))]
50        if let Some(cpu) = cpu.get_feature() {
51            return ffi_arm_neon::State::new_context(key, cpu);
52        }
53        let _: cpu::Features = cpu;
54        ffi_fallback::State::new_context(key)
55    }
56
57    pub fn update_block(&mut self, input: [u8; BLOCK_LEN]) {
58        self.update(AsChunks::from_ref(&input))
59    }
60
61    pub fn update(&mut self, input: AsChunks<u8, BLOCK_LEN>) {
62        self.update_internal(input.as_flattened());
63    }
64
65    fn update_internal(&mut self, input: &[u8]) {
66        match self {
67            #[cfg(all(target_arch = "arm", target_endian = "little"))]
68            Self::ArmNeon(state) => state.update_internal(input),
69            Self::Fallback(state) => state.update_internal(input),
70        }
71    }
72
73    pub(super) fn finish(mut self, input: &[u8]) -> Tag {
74        self.update_internal(input);
75        match self {
76            #[cfg(all(target_arch = "arm", target_endian = "little"))]
77            Self::ArmNeon(state) => state.finish(),
78            Self::Fallback(state) => state.finish(),
79        }
80    }
81}
82
83/// Implements the original, non-IETF padding semantics.
84///
85/// This is used by chacha20_poly1305_openssh and the standalone
86/// poly1305 test vectors.
87pub(super) fn sign(key: Key, input: &[u8], cpu_features: cpu::Features) -> Tag {
88    let ctx = Context::from_key(key, cpu_features);
89    ctx.finish(input)
90}
91
92#[cfg(test)]
93mod tests {
94    use super::*;
95    use crate::testutil as test;
96
97    // Adapted from BoringSSL's crypto/poly1305/poly1305_test.cc.
98    #[test]
99    pub fn test_poly1305() {
100        let cpu_features = cpu::features();
101        test::run(
102            test_vector_file!("poly1305_test.txt"),
103            |section, test_case| {
104                assert_eq!(section, "");
105                let key = test_case.consume_bytes("Key");
106                let key: &[u8; KEY_LEN] = key.as_slice().try_into().unwrap();
107                let input = test_case.consume_bytes("Input");
108                let expected_mac = test_case.consume_bytes("MAC");
109                let key = Key::new(*key);
110                let Tag(actual_mac) = sign(key, &input, cpu_features);
111                assert_eq!(expected_mac, actual_mac.as_ref());
112
113                Ok(())
114            },
115        )
116    }
117}
ring/aead/poly1305.rs

ring/aead/
poly1305.rs
