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Simplify operations with SecretBox
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@fjarri
fjarri committed Dec 3, 2024
1 parent 9846887 commit 07b750d
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Showing 33 changed files with 1,498 additions and 1,062 deletions.
13 changes: 5 additions & 8 deletions synedrion/src/cggmp21/aux_gen.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,6 @@
//! that only generates the auxiliary data.
use alloc::{
boxed::Box,
collections::{BTreeMap, BTreeSet},
format,
string::String,
Expand All @@ -17,7 +16,6 @@ use manul::protocol::{
ReceiveError, Round, RoundId, Serializer,
};
use rand_core::CryptoRngCore;
use secrecy::SecretBox;
use serde::{Deserialize, Serialize};

use super::{
Expand All @@ -34,7 +32,7 @@ use crate::{
tools::{
bitvec::BitVec,
hashing::{Chain, FofHasher, HashOutput},
DowncastMap, Without,
DowncastMap, Secret, Without,
},
};

Expand Down Expand Up @@ -138,7 +136,7 @@ impl<P: SchemeParams, I: PartyId> EntryPoint<I> for AuxGen<P, I> {
let paillier_pk = paillier_sk.public_key();

// El-Gamal key
let y = Scalar::random(rng);
let y = Secret::init_with(|| Scalar::random(rng));
let cap_y = y.mul_by_generator();

// The secret and the commitment for the Schnorr PoK of the El-Gamal key
Expand Down Expand Up @@ -208,7 +206,7 @@ struct PublicData1Precomp<P: SchemeParams> {
#[derive(Debug)]
struct Context<P: SchemeParams, I> {
paillier_sk: SecretKeyPaillier<P::Paillier>,
y: Scalar,
y: Secret<Scalar>,
tau_y: SchSecret,
data_precomp: PublicData1Precomp<P>,
my_id: I,
Expand Down Expand Up @@ -613,7 +611,7 @@ impl<P: SchemeParams, I: PartyId + Serialize> Round<I> for Round3<P, I> {

let secret_aux = SecretAuxInfo {
paillier_sk: self.context.paillier_sk.into_wire(),
el_gamal_sk: SecretBox::new(Box::new(self.context.y)),
el_gamal_sk: self.context.y,
};

let aux_info = AuxInfo {
Expand All @@ -635,7 +633,6 @@ mod tests {
session::signature::Keypair,
};
use rand_core::OsRng;
use secrecy::ExposeSecret;

use super::AuxGen;
use crate::cggmp21::TestParams;
Expand Down Expand Up @@ -664,7 +661,7 @@ mod tests {
for (id, aux_info) in aux_infos.iter() {
for other_aux_info in aux_infos.values() {
assert_eq!(
aux_info.secret_aux.el_gamal_sk.expose_secret().mul_by_generator(),
aux_info.secret_aux.el_gamal_sk.mul_by_generator(),
other_aux_info.public_aux[id].el_gamal_pk
);
}
Expand Down
45 changes: 21 additions & 24 deletions synedrion/src/cggmp21/entities.rs
View file
Original file line number Diff line number Diff line change
@@ -1,22 +1,21 @@
use alloc::{
boxed::Box,
collections::{BTreeMap, BTreeSet},
vec::Vec,
};
use core::{fmt::Debug, marker::PhantomData};

use k256::ecdsa::VerifyingKey;
use rand_core::CryptoRngCore;
use secrecy::{ExposeSecret, SecretBox};
use serde::{Deserialize, Serialize};

use crate::{
cggmp21::SchemeParams,
curve::{Point, Scalar},
curve::{secret_split, Point, Scalar},
paillier::{
Ciphertext, PaillierParams, PublicKeyPaillier, PublicKeyPaillierWire, RPParams, RPParamsWire, RandomizerWire,
Ciphertext, PaillierParams, PublicKeyPaillier, PublicKeyPaillierWire, RPParams, RPParamsWire, Randomizer,
SecretKeyPaillier, SecretKeyPaillierWire,
},
tools::Secret,
uint::Signed,
};

Expand All @@ -25,7 +24,7 @@ use crate::{
pub struct KeyShare<P, I: Ord> {
pub(crate) owner: I,
/// Secret key share of this node.
pub(crate) secret_share: SecretBox<Scalar>, // `x_i`
pub(crate) secret_share: Secret<Scalar>, // `x_i`
pub(crate) public_shares: BTreeMap<I, Point>, // `X_j`
// TODO (#27): this won't be needed when Scalar/Point are a part of `P`
pub(crate) phantom: PhantomData<P>,
Expand All @@ -44,7 +43,7 @@ pub struct AuxInfo<P: SchemeParams, I: Ord> {
#[serde(bound(deserialize = "SecretKeyPaillierWire<P::Paillier>: for <'x> Deserialize<'x>"))]
pub(crate) struct SecretAuxInfo<P: SchemeParams> {
pub(crate) paillier_sk: SecretKeyPaillierWire<P::Paillier>,
pub(crate) el_gamal_sk: SecretBox<Scalar>, // `y_i`
pub(crate) el_gamal_sk: Secret<Scalar>, // `y_i`
}

#[derive(Debug, Clone, Serialize, Deserialize)]
Expand All @@ -68,7 +67,7 @@ pub(crate) struct AuxInfoPrecomputed<P: SchemeParams, I> {
pub(crate) struct SecretAuxInfoPrecomputed<P: SchemeParams> {
pub(crate) paillier_sk: SecretKeyPaillier<P::Paillier>,
#[allow(dead_code)] // TODO (#36): this will be needed for the 6-round presigning protocol.
pub(crate) el_gamal_sk: SecretBox<Scalar>, // `y_i`
pub(crate) el_gamal_sk: Secret<Scalar>, // `y_i`
}

#[derive(Debug, Clone)]
Expand All @@ -84,7 +83,7 @@ pub(crate) struct PublicAuxInfoPrecomputed<P: SchemeParams> {
pub struct KeyShareChange<P: SchemeParams, I: Ord> {
pub(crate) owner: I,
/// The value to be added to the secret share.
pub(crate) secret_share_change: SecretBox<Scalar>, // `x_i^* - x_i == \sum_{j} x_j^i`
pub(crate) secret_share_change: Secret<Scalar>, // `x_i^* - x_i == \sum_{j} x_j^i`
/// The values to be added to the public shares of remote nodes.
pub(crate) public_share_changes: BTreeMap<I, Point>, // `X_k^* - X_k == \sum_j X_j^k`, for all nodes
// TODO (#27): this won't be needed when Scalar/Point are a part of `P`
Expand All @@ -96,13 +95,13 @@ pub struct KeyShareChange<P: SchemeParams, I: Ord> {
pub(crate) struct PresigningData<P: SchemeParams, I> {
pub(crate) nonce: Scalar, // x-coordinate of $R$
/// An additive share of the ephemeral scalar.
pub(crate) ephemeral_scalar_share: SecretBox<Scalar>, // $k_i$
pub(crate) ephemeral_scalar_share: Secret<Scalar>, // $k_i$
/// An additive share of `k * x` where `x` is the secret key.
pub(crate) product_share: SecretBox<Scalar>,
pub(crate) product_share: Secret<Scalar>,

// Values generated during presigning,
// kept in case we need to generate a proof of correctness.
pub(crate) product_share_nonreduced: Signed<<P::Paillier as PaillierParams>::Uint>,
pub(crate) product_share_nonreduced: Secret<Signed<<P::Paillier as PaillierParams>::Uint>>,

// $K_i$.
pub(crate) cap_k: Ciphertext<P::Paillier>,
Expand All @@ -113,9 +112,9 @@ pub(crate) struct PresigningData<P: SchemeParams, I> {

#[derive(Debug, Clone)]
pub(crate) struct PresigningValues<P: SchemeParams> {
pub(crate) hat_beta: SecretBox<Signed<<P::Paillier as PaillierParams>::Uint>>,
pub(crate) hat_r: RandomizerWire<P::Paillier>,
pub(crate) hat_s: RandomizerWire<P::Paillier>,
pub(crate) hat_beta: Secret<Signed<<P::Paillier as PaillierParams>::Uint>>,
pub(crate) hat_r: Randomizer<P::Paillier>,
pub(crate) hat_s: Randomizer<P::Paillier>,
pub(crate) cap_k: Ciphertext<P::Paillier>,
/// Received $\hat{D}_{i,j}$.
pub(crate) hat_cap_d_received: Ciphertext<P::Paillier>,
Expand All @@ -130,13 +129,11 @@ impl<P: SchemeParams, I: Clone + Ord + PartialEq + Debug> KeyShare<P, I> {
// TODO (#68): check that party_idx is the same for both, and the number of parties is the same
assert_eq!(self.owner, change.owner);

let secret_share = SecretBox::new(Box::new(
self.secret_share.expose_secret() + change.secret_share_change.expose_secret(),
));
let secret_share = self.secret_share + change.secret_share_change;
let public_shares = self
.public_shares
.iter()
.map(|(id, public_share)| (id.clone(), public_share + &change.public_share_changes[id]))
.map(|(id, public_share)| (id.clone(), *public_share + change.public_share_changes[id]))
.collect();

Self {
Expand All @@ -154,12 +151,12 @@ impl<P: SchemeParams, I: Clone + Ord + PartialEq + Debug> KeyShare<P, I> {
ids: &BTreeSet<I>,
signing_key: Option<&k256::ecdsa::SigningKey>,
) -> BTreeMap<I, Self> {
let secret = match signing_key {
let secret = Secret::init_with(|| match signing_key {
None => Scalar::random(rng),
Some(sk) => Scalar::from(sk.as_nonzero_scalar()),
};
});

let secret_shares = secret.split(rng, ids.len());
let secret_shares = secret_split(rng, secret, ids.len());
let public_shares = ids
.iter()
.zip(secret_shares.iter())
Expand All @@ -173,7 +170,7 @@ impl<P: SchemeParams, I: Clone + Ord + PartialEq + Debug> KeyShare<P, I> {
id.clone(),
KeyShare {
owner: id.clone(),
secret_share: SecretBox::new(Box::new(secret_share)),
secret_share,
public_shares: public_shares.clone(),
phantom: PhantomData,
},
Expand Down Expand Up @@ -216,7 +213,7 @@ impl<P: SchemeParams, I: Ord + Clone> AuxInfo<P, I> {
let secret_aux = (0..ids.len())
.map(|_| SecretAuxInfo {
paillier_sk: SecretKeyPaillierWire::<P::Paillier>::random(rng),
el_gamal_sk: SecretBox::new(Box::new(Scalar::random(rng))),
el_gamal_sk: Secret::init_with(|| Scalar::random(rng)),
})
.collect::<Vec<_>>();

Expand All @@ -228,7 +225,7 @@ impl<P: SchemeParams, I: Ord + Clone> AuxInfo<P, I> {
id.clone(),
PublicAuxInfo {
paillier_pk: secret.paillier_sk.public_key(),
el_gamal_pk: secret.el_gamal_sk.expose_secret().mul_by_generator(),
el_gamal_pk: secret.el_gamal_sk.mul_by_generator(),
rp_params: RPParams::random(rng).to_wire(),
},
)
Expand Down
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