phoenix_core/
stealth_address.rs

1// This Source Code Form is subject to the terms of the Mozilla Public
2// License, v. 2.0. If a copy of the MPL was not distributed with this
3// file, You can obtain one at http://mozilla.org/MPL/2.0/.
4//
5// Copyright (c) DUSK NETWORK. All rights reserved.
6
7use dusk_bytes::{DeserializableSlice, Error, Serializable};
8use dusk_jubjub::{JubJubAffine, JubJubExtended};
9use jubjub_schnorr::PublicKey as NotePublicKey;
10#[cfg(feature = "rkyv-impl")]
11use rkyv::{Archive, Deserialize, Serialize};
12use subtle::{Choice, ConstantTimeEq};
13
14/// To obfuscate the identity of the participants, we utilizes a Stealth Address
15/// system.
16/// A `StealthAddress` is composed by a one-time note-public-key (the actual
17/// address) and a random point `R`.
18#[derive(Default, Debug, Clone, Copy, Eq)]
19#[cfg_attr(
20    feature = "rkyv-impl",
21    derive(Archive, Serialize, Deserialize),
22    archive_attr(derive(bytecheck::CheckBytes))
23)]
24pub struct StealthAddress {
25    pub(crate) R: JubJubExtended,
26    pub(crate) note_pk: NotePublicKey,
27}
28
29impl StealthAddress {
30    /// Create a stealth address from its internal parts
31    ///
32    /// A stealth address is intended to be generated as the public counterpart
33    /// of a one time secret key. If the user opts to generate the
34    /// stealth address from points, there is no guarantee a secret one time
35    /// key counterpart will be known, and this stealth address will
36    /// not provide the required arguments to generate it.
37    ///
38    /// For additional information, check [PublicKey::from_raw_unchecked].
39    pub const fn from_raw_unchecked(
40        R: JubJubExtended,
41        note_pk: NotePublicKey,
42    ) -> Self {
43        Self { R, note_pk }
44    }
45
46    /// Gets the random point `R`
47    pub const fn R(&self) -> &JubJubExtended {
48        &self.R
49    }
50
51    /// Gets the `note_pk`
52    pub const fn note_pk(&self) -> &NotePublicKey {
53        &self.note_pk
54    }
55
56    /// Decode a historical stealth address without enforcing subgroup checks
57    /// on the underlying points.
58    pub fn from_bytes_legacy_compat(
59        bytes: &[u8; Self::SIZE],
60    ) -> Result<Self, Error> {
61        let r_affine = affine_from_slice_legacy_compat(&bytes[..32])?;
62        let note_pk_affine = affine_from_slice_legacy_compat(&bytes[32..])?;
63
64        Ok(Self {
65            R: JubJubExtended::from(r_affine),
66            note_pk: NotePublicKey::from_raw_unchecked(JubJubExtended::from(
67                note_pk_affine,
68            )),
69        })
70    }
71}
72
73impl ConstantTimeEq for StealthAddress {
74    fn ct_eq(&self, other: &Self) -> Choice {
75        self.note_pk().as_ref().ct_eq(other.note_pk().as_ref())
76            & self.R.ct_eq(&other.R)
77    }
78}
79
80impl PartialEq for StealthAddress {
81    fn eq(&self, other: &Self) -> bool {
82        self.ct_eq(other).into()
83    }
84}
85
86impl Serializable<64> for StealthAddress {
87    type Error = Error;
88    /// Encode the `StealthAddress` to an array of 64 bytes
89    fn to_bytes(&self) -> [u8; Self::SIZE] {
90        let mut bytes = [0u8; Self::SIZE];
91        bytes[..32].copy_from_slice(&JubJubAffine::from(self.R).to_bytes());
92        bytes[32..].copy_from_slice(
93            &JubJubAffine::from(self.note_pk().as_ref()).to_bytes(),
94        );
95        bytes
96    }
97
98    /// Decode the `StealthAddress` from an array of 64 bytes
99    fn from_bytes(bytes: &[u8; Self::SIZE]) -> Result<Self, Error> {
100        let R = JubJubExtended::from(JubJubAffine::from_slice(&bytes[..32])?);
101        let note_pk =
102            JubJubExtended::from(JubJubAffine::from_slice(&bytes[32..])?);
103        let note_pk = NotePublicKey::from_raw_unchecked(note_pk);
104
105        Ok(StealthAddress { R, note_pk })
106    }
107}
108
109pub(crate) fn affine_from_slice_legacy_compat(
110    bytes: &[u8],
111) -> Result<JubJubAffine, Error> {
112    let mut point = [0u8; JubJubAffine::SIZE];
113    point.copy_from_slice(bytes);
114    Option::<JubJubAffine>::from(JubJubAffine::from_bytes(point))
115        .ok_or(Error::InvalidData)
116}
phoenix_core/stealth_address.rs

phoenix_core/
stealth_address.rs
