hpke_dispatch/
kem.rs

1use crate::{IdLookupError, Keypair};
2use num_enum::TryFromPrimitive;
3use std::str::FromStr;
4
5#[cfg(target_arch = "wasm32")]
6use wasm_bindgen::prelude::*;
7
8/**
9Kem represents an asymmetric key encapsulation mechanism, as per
10[RFC9180§7.1][section-7.1]. Currently only four of the options listed in
11the hpke draft are available.
12
13[section-7.1]: https://www.rfc-editor.org/rfc/rfc9180.html#section-7.1
14*/
15#[non_exhaustive]
16#[repr(u16)]
17#[derive(Copy, Clone, Debug, PartialEq, Eq, TryFromPrimitive)]
18#[cfg_attr(
19    feature = "serde",
20    derive(serde_crate::Serialize, serde_crate::Deserialize)
21)]
22#[cfg_attr(feature = "serde", serde(crate = "serde_crate"))]
23#[cfg_attr(feature = "cfg_eval", cfg_eval)]
24#[cfg_attr(target_arch = "wasm32", wasm_bindgen)]
25pub enum Kem {
26    /// DHKEM(P-256, HKDF-SHA256) [NISTCurves](https://doi.org/10.6028/nist.fips.186-4)
27    #[cfg(feature = "kem-dh-p256-hkdf-sha256")]
28    DhP256HkdfSha256 = 16,
29
30    /// DHKEM(P-384, HKDF-SHA384) [NISTCurves](https://doi.org/10.6028/nist.fips.186-4)
31    #[cfg(feature = "kem-dh-p384-hkdf-sha384")]
32    DhP384HkdfSha384 = 17,
33
34    /// DHKEM(P-521, HKDF-SHA512) [NISTCurves](https://doi.org/10.6028/nist.fips.186-4)
35    #[cfg(feature = "kem-dh-p521-hkdf-sha512")]
36    DhP521HkdfSha512 = 18,
37
38    /// DHKEM(X25519, HKDF-SHA256) [RFC7748](https://www.rfc-editor.org/info/rfc7748)
39    #[cfg(feature = "kem-x25519-hkdf-sha256")]
40    X25519HkdfSha256 = 32,
41}
42
43impl FromStr for Kem {
44    type Err = IdLookupError;
45
46    fn from_str(s: &str) -> Result<Self, Self::Err> {
47        match &*s.to_lowercase().replace('-', "") {
48            #[cfg(feature = "kem-dh-p256-hkdf-sha256")]
49            "p256sha256" | "dhkemp256hkdfsha256" | "p256hkdfsha256" | "dhkem(p256, hkdfsha256)" => {
50                Ok(Self::DhP256HkdfSha256)
51            }
52            #[cfg(feature = "kem-dh-p384-hkdf-sha384")]
53            "p384sha384" | "dhkemp384hkdfsha384" | "p384hkdfsha384" | "dhkem(p384, hkdfsha384)" => {
54                Ok(Self::DhP384HkdfSha384)
55            }
56            #[cfg(feature = "kem-dh-p521-hkdf-sha512")]
57            "p521sha512" | "dhkemp521hkdfsha512" | "p521hkdfsha512" | "dhkem(p521, hkdfsha512)" => {
58                Ok(Self::DhP521HkdfSha512)
59            }
60            #[cfg(feature = "kem-x25519-hkdf-sha256")]
61            "x25519sha256"
62            | "dhkemx25519hkdfsha256"
63            | "x25519hkdfsha256"
64            | "dhkem(x25519, hkdfsha256)" => Ok(Self::X25519HkdfSha256),
65            _ => Err(IdLookupError("kem not recognized")),
66        }
67    }
68}
69
70impl Kem {
71    /// generate a [`Keypair`] for this [`Kem`].
72    #[must_use]
73    pub fn gen_keypair(self) -> Keypair {
74        crate::gen_keypair(self)
75    }
76}
77
78/// An iterable slice of [`Kem`] variants
79pub const KEM_ALL: &[Kem] = &[
80    #[cfg(feature = "kem-dh-p256-hkdf-sha256")]
81    Kem::DhP256HkdfSha256,
82    #[cfg(feature = "kem-dh-p384-hkdf-sha384")]
83    Kem::DhP384HkdfSha384,
84    #[cfg(feature = "kem-dh-p521-hkdf-sha512")]
85    Kem::DhP521HkdfSha512,
86    #[cfg(feature = "kem-x25519-hkdf-sha256")]
87    Kem::X25519HkdfSha256,
88];
hpke_dispatch/kem.rs

hpke_dispatch/
kem.rs
