basil_cose/
alg.rs

1// SPDX-FileCopyrightText: 2026 OpenBasil Contributors
2//
3// SPDX-License-Identifier: Apache-2.0
4
5//! Closed algorithm enums and their COSE codepoints.
6//!
7//! Decode of any codepoint outside these enums is a
8//! [`DecodeError::UnknownAlgorithm`](crate::DecodeError::UnknownAlgorithm).
9//! There are no forward-compatible `Unknown` arms.
10
11/// Signature algorithms in the profile allow-set.
12#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
13pub enum SignatureAlgorithm {
14    /// `EdDSA` (COSE codepoint -8), Ed25519 keys.
15    EdDsa,
16    /// `ES256` (COSE codepoint -7): ECDSA with NIST P-256 and SHA-256.
17    Es256,
18}
19
20impl SignatureAlgorithm {
21    /// The COSE algorithm codepoint.
22    #[must_use]
23    pub const fn codepoint(self) -> i64 {
24        match self {
25            Self::EdDsa => -8,
26            Self::Es256 => -7,
27        }
28    }
29
30    /// Look a codepoint up in the allow-set.
31    #[must_use]
32    pub const fn from_codepoint(alg: i64) -> Option<Self> {
33        match alg {
34            -8 => Some(Self::EdDsa),
35            -7 => Some(Self::Es256),
36            _ => None,
37        }
38    }
39}
40
41/// Key-agreement algorithms in the profile allow-set.
42#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
43pub enum KeyAgreementAlgorithm {
44    /// ECDH-ES + HKDF-256 (COSE codepoint -25), X25519 keys.
45    EcdhEsHkdf256,
46}
47
48impl KeyAgreementAlgorithm {
49    /// The COSE algorithm codepoint.
50    #[must_use]
51    pub const fn codepoint(self) -> i64 {
52        match self {
53            Self::EcdhEsHkdf256 => -25,
54        }
55    }
56
57    /// Look a codepoint up in the allow-set.
58    #[must_use]
59    pub const fn from_codepoint(alg: i64) -> Option<Self> {
60        match alg {
61            -25 => Some(Self::EcdhEsHkdf256),
62            _ => None,
63        }
64    }
65}
66
67/// Content-encryption algorithms in the profile allow-set.
68///
69/// A parameter of every encrypting entry point: basil invocation v1 passes
70/// [`ContentAlgorithm::A256Gcm`]; clients may use
71/// [`ContentAlgorithm::ChaCha20Poly1305`].
72#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
73pub enum ContentAlgorithm {
74    /// AES-256-GCM (COSE codepoint 3).
75    A256Gcm,
76    /// `ChaCha20`-`Poly1305` (COSE codepoint 24).
77    ChaCha20Poly1305,
78}
79
80impl ContentAlgorithm {
81    /// The COSE algorithm codepoint.
82    #[must_use]
83    pub const fn codepoint(self) -> i64 {
84        match self {
85            Self::A256Gcm => 3,
86            Self::ChaCha20Poly1305 => 24,
87        }
88    }
89
90    /// Look a codepoint up in the allow-set.
91    #[must_use]
92    pub const fn from_codepoint(alg: i64) -> Option<Self> {
93        match alg {
94            3 => Some(Self::A256Gcm),
95            24 => Some(Self::ChaCha20Poly1305),
96            _ => None,
97        }
98    }
99
100    /// The content-encryption key length in bytes (256 bits for both).
101    #[must_use]
102    pub const fn key_len(self) -> usize {
103        32
104    }
105}
basil_cose/alg.rs

basil_cose/
alg.rs
