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Smash key-gen out of processor

Browse source 
Resolves some bad assumptions made regarding keys being unique or not.
This commit is contained in:
Luke Parker 2024-08-16 17:01:45 -04:00
parent f3b91bd44f
commit 2f29c91d30
9 changed files with 335 additions and 312 deletions
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21
Cargo.lock generated
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@ -8564,7 +8564,6 @@ version = "0.1.0"
dependencies = [
"async-trait",
"bitcoin-serai",
"blake2",
"borsh",
"ciphersuite",
"const-hex",
@ -8600,6 +8599,26 @@ dependencies = [
"zeroize",
]
[[package]]
name = "serai-processor-key-gen"
version = "0.1.0"
dependencies = [
"blake2",
"borsh",
"ciphersuite",
"dkg",
"ec-divisors",
"flexible-transcript",
"log",
"parity-scale-codec",
"rand_chacha",
"rand_core",
"serai-db",
"serai-processor-messages",
"serai-validator-sets-primitives",
"zeroize",
]
[[package]]
name = "serai-processor-messages"
version = "0.1.0"

1
processor/Cargo.toml
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@ -36,7 +36,6 @@ serde_json = { version = "1", default-features = false, features = ["std"] }
# Cryptography
ciphersuite = { path = "../crypto/ciphersuite", default-features = false, features = ["std", "ristretto"] }
blake2 = { version = "0.10", default-features = false, features = ["std"] }
transcript = { package = "flexible-transcript", path = "../crypto/transcript", default-features = false, features = ["std"] }
ec-divisors = { package = "ec-divisors", path = "../crypto/evrf/divisors", default-features = false }
dkg = { package = "dkg", path = "../crypto/dkg", default-features = false, features = ["std", "evrf-ristretto"] }

80
processor/key-gen/Cargo.toml
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@ -13,85 +13,35 @@ publish = false
all-features = true
rustdoc-args = ["--cfg", "docsrs"]
[package.metadata.cargo-machete]
ignored = ["scale"]
[lints]
workspace = true
[dependencies]
# Macros
async-trait = { version = "0.1", default-features = false }
zeroize = { version = "1", default-features = false, features = ["std"] }
thiserror = { version = "1", default-features = false }
# Libs
rand_core = { version = "0.6", default-features = false, features = ["std", "getrandom"] }
rand_chacha = { version = "0.3", default-features = false, features = ["std"] }
# Cryptography
blake2 = { version = "0.10", default-features = false, features = ["std"] }
transcript = { package = "flexible-transcript", path = "../../crypto/transcript", default-features = false, features = ["std"] }
ec-divisors = { package = "ec-divisors", path = "../../crypto/evrf/divisors", default-features = false }
ciphersuite = { path = "../../crypto/ciphersuite", default-features = false, features = ["std", "ristretto"] }
dkg = { package = "dkg", path = "../../crypto/dkg", default-features = false, features = ["std", "evrf-ristretto"] }
# Substrate
serai-validator-sets-primitives = { path = "../../substrate/validator-sets/primitives", default-features = false, features = ["std"] }
# Encoders
const-hex = { version = "1", default-features = false }
hex = { version = "0.4", default-features = false, features = ["std"] }
scale = { package = "parity-scale-codec", version = "3", default-features = false, features = ["std"] }
borsh = { version = "1", default-features = false, features = ["std", "derive", "de_strict_order"] }
serde_json = { version = "1", default-features = false, features = ["std"] }
# Cryptography
ciphersuite = { path = "../crypto/ciphersuite", default-features = false, features = ["std", "ristretto"] }
blake2 = { version = "0.10", default-features = false, features = ["std"] }
transcript = { package = "flexible-transcript", path = "../crypto/transcript", default-features = false, features = ["std"] }
ec-divisors = { package = "ec-divisors", path = "../crypto/evrf/divisors", default-features = false }
dkg = { package = "dkg", path = "../crypto/dkg", default-features = false, features = ["std", "evrf-ristretto"] }
frost = { package = "modular-frost", path = "../crypto/frost", default-features = false, features = ["ristretto"] }
frost-schnorrkel = { path = "../crypto/schnorrkel", default-features = false }
# Bitcoin/Ethereum
k256 = { version = "^0.13.1", default-features = false, features = ["std"], optional = true }
# Bitcoin
secp256k1 = { version = "0.29", default-features = false, features = ["std", "global-context", "rand-std"], optional = true }
bitcoin-serai = { path = "../networks/bitcoin", default-features = false, features = ["std"], optional = true }
# Ethereum
ethereum-serai = { path = "../networks/ethereum", default-features = false, optional = true }
# Monero
dalek-ff-group = { path = "../crypto/dalek-ff-group", default-features = false, features = ["std"], optional = true }
monero-simple-request-rpc = { path = "../networks/monero/rpc/simple-request", default-features = false, optional = true }
monero-wallet = { path = "../networks/monero/wallet", default-features = false, features = ["std", "multisig", "compile-time-generators"], optional = true }
# Application
log = { version = "0.4", default-features = false, features = ["std"] }
env_logger = { version = "0.10", default-features = false, features = ["humantime"], optional = true }
tokio = { version = "1", default-features = false, features = ["rt-multi-thread", "sync", "time", "macros"] }
zalloc = { path = "../common/zalloc" }
serai-db = { path = "../common/db" }
serai-env = { path = "../common/env", optional = true }
# TODO: Replace with direct usage of primitives
serai-client = { path = "../substrate/client", default-features = false, features = ["serai"] }
messages = { package = "serai-processor-messages", path = "./messages" }
message-queue = { package = "serai-message-queue", path = "../message-queue", optional = true }
[dev-dependencies]
frost = { package = "modular-frost", path = "../crypto/frost", features = ["tests"] }
sp-application-crypto = { git = "https://github.com/serai-dex/substrate", default-features = false, features = ["std"] }
ethereum-serai = { path = "../networks/ethereum", default-features = false, features = ["tests"] }
dockertest = "0.4"
serai-docker-tests = { path = "../tests/docker" }
[features]
secp256k1 = ["k256", "dkg/evrf-secp256k1", "frost/secp256k1"]
bitcoin = ["dep:secp256k1", "secp256k1", "bitcoin-serai", "serai-client/bitcoin"]
ethereum = ["secp256k1", "ethereum-serai/tests"]
ed25519 = ["dalek-ff-group", "dkg/evrf-ed25519", "frost/ed25519"]
monero = ["ed25519", "monero-simple-request-rpc", "monero-wallet", "serai-client/monero"]
binaries = ["env_logger", "serai-env", "message-queue"]
parity-db = ["serai-db/parity-db"]
rocksdb = ["serai-db/rocksdb"]
serai-db = { path = "../../common/db" }
messages = { package = "serai-processor-messages", path = "../messages" }

8
processor/key-gen/README.md Normal file
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@ -0,0 +1,8 @@
# Key Generation
This library implements the Distributed Key Generation (DKG) for the Serai
protocol. Two invocations of the eVRF-based DKG are performed, one for Ristretto
(to have a key to oraclize values onto the Serai blockchain with) and one for
the external network's curve.
This library is interacted with via the `serai-processor-messages::key_gen` API.

144
processor/key-gen/src/db.rs Normal file
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@ -0,0 +1,144 @@
use core::marker::PhantomData;
use std::collections::HashMap;
use zeroize::Zeroizing;
use ciphersuite::{group::GroupEncoding, Ciphersuite, Ristretto};
use dkg::{Participant, ThresholdCore, ThresholdKeys, evrf::EvrfCurve};
use serai_validator_sets_primitives::Session;
use borsh::{BorshSerialize, BorshDeserialize};
use serai_db::{Get, DbTxn, create_db};
use crate::KeyGenParams;
pub(crate) struct Params<P: KeyGenParams> {
pub(crate) t: u16,
pub(crate) n: u16,
pub(crate) substrate_evrf_public_keys:
Vec<<<Ristretto as EvrfCurve>::EmbeddedCurve as Ciphersuite>::G>,
pub(crate) network_evrf_public_keys:
Vec<<<P::ExternalNetworkCurve as EvrfCurve>::EmbeddedCurve as Ciphersuite>::G>,
}
#[derive(BorshSerialize, BorshDeserialize)]
struct RawParams {
t: u16,
substrate_evrf_public_keys: Vec<[u8; 32]>,
network_evrf_public_keys: Vec<Vec<u8>>,
}
#[derive(BorshSerialize, BorshDeserialize)]
pub(crate) struct Participations {
pub(crate) substrate_participations: HashMap<Participant, Vec<u8>>,
pub(crate) network_participations: HashMap<Participant, Vec<u8>>,
}
create_db!(
KeyGenDb {
ParamsDb: (session: &Session) -> RawParams,
ParticipationsDb: (session: &Session) -> Participations,
KeySharesDb: (session: &Session) -> Vec<u8>,
}
);
pub(crate) struct KeyGenDb<P: KeyGenParams>(PhantomData<P>);
impl<P: KeyGenParams> KeyGenDb<P> {
pub(crate) fn set_params(txn: &mut impl DbTxn, session: Session, params: Params<P>) {
assert_eq!(params.substrate_evrf_public_keys.len(), params.network_evrf_public_keys.len());
ParamsDb::set(
txn,
&session,
&RawParams {
t: params.t,
substrate_evrf_public_keys: params
.substrate_evrf_public_keys
.into_iter()
.map(|key| key.to_bytes())
.collect(),
network_evrf_public_keys: params
.network_evrf_public_keys
.into_iter()
.map(|key| key.to_bytes().as_ref().to_vec())
.collect(),
},
)
}
pub(crate) fn params(getter: &impl Get, session: Session) -> Option<Params<P>> {
ParamsDb::get(getter, &session).map(|params| Params {
t: params.t,
n: params
.network_evrf_public_keys
.len()
.try_into()
.expect("amount of keys exceeded the amount allowed during a DKG"),
substrate_evrf_public_keys: params
.substrate_evrf_public_keys
.into_iter()
.map(|key| {
<<Ristretto as EvrfCurve>::EmbeddedCurve as Ciphersuite>::read_G(&mut key.as_slice())
.unwrap()
})
.collect(),
network_evrf_public_keys: params
.network_evrf_public_keys
.into_iter()
.map(|key| {
<<P::ExternalNetworkCurve as EvrfCurve>::EmbeddedCurve as Ciphersuite>::read_G::<&[u8]>(
&mut key.as_ref(),
)
.unwrap()
})
.collect(),
})
}
pub(crate) fn set_participations(
txn: &mut impl DbTxn,
session: Session,
participations: &Participations,
) {
ParticipationsDb::set(txn, &session, participations)
}
pub(crate) fn participations(getter: &impl Get, session: Session) -> Option<Participations> {
ParticipationsDb::get(getter, &session)
}
pub(crate) fn set_key_shares(
txn: &mut impl DbTxn,
session: Session,
substrate_keys: &[ThresholdKeys<Ristretto>],
network_keys: &[ThresholdKeys<P::ExternalNetworkCurve>],
) {
assert_eq!(substrate_keys.len(), network_keys.len());
let mut keys = Zeroizing::new(vec![]);
for (substrate_keys, network_keys) in substrate_keys.iter().zip(network_keys) {
keys.extend(substrate_keys.serialize().as_slice());
keys.extend(network_keys.serialize().as_slice());
}
KeySharesDb::set(txn, &session, &keys);
}
#[allow(clippy::type_complexity)]
pub(crate) fn key_shares(
getter: &impl Get,
session: Session,
) -> Option<(Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<P::ExternalNetworkCurve>>)> {
let keys = KeySharesDb::get(getter, &session)?;
let mut keys: &[u8] = keys.as_ref();
let mut substrate_keys = vec![];
let mut network_keys = vec![];
while !keys.is_empty() {
substrate_keys.push(ThresholdKeys::new(ThresholdCore::read(&mut keys).unwrap()));
let mut these_network_keys = ThresholdKeys::new(ThresholdCore::read(&mut keys).unwrap());
P::tweak_keys(&mut these_network_keys);
network_keys.push(these_network_keys);
}
Some((substrate_keys, network_keys))
}
}

38
processor/key-gen/src/generators.rs Normal file
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@ -0,0 +1,38 @@
use core::any::{TypeId, Any};
use std::{
sync::{LazyLock, Mutex},
collections::HashMap,
};
use dkg::evrf::*;
use serai_validator_sets_primitives::MAX_KEY_SHARES_PER_SET;
/// A cache of the generators used by the eVRF DKG.
///
/// This performs a lookup of the Ciphersuite to its generators. Since the Ciphersuite is a
/// generic, this takes advantage of `Any`. This static is isolated in a module to ensure
/// correctness can be evaluated solely by reviewing these few lines of code.
///
/// This is arguably over-engineered as of right now, as we only need generators for Ristretto
/// and N::Curve. By having this HashMap, we enable de-duplication of the Ristretto == N::Curve
/// case, and we automatically support the n-curve case (rather than hard-coding to the 2-curve
/// case).
static GENERATORS: LazyLock<Mutex<HashMap<TypeId, &'static (dyn Send + Sync + Any)>>> =
LazyLock::new(|| Mutex::new(HashMap::new()));
pub(crate) fn generators<C: EvrfCurve>() -> &'static EvrfGenerators<C> {
GENERATORS
.lock()
.unwrap()
.entry(TypeId::of::<C>())
.or_insert_with(|| {
// If we haven't prior needed generators for this Ciphersuite, generate new ones
Box::leak(Box::new(EvrfGenerators::<C>::new(
((MAX_KEY_SHARES_PER_SET * 2 / 3) + 1).try_into().unwrap(),
MAX_KEY_SHARES_PER_SET.try_into().unwrap(),
)))
})
.downcast_ref()
.unwrap()
}

351
processor/key-gen/src/lib.rs
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@ -1,7 +1,8 @@
use std::{
io,
collections::{HashSet, HashMap},
};
#![cfg_attr(docsrs, feature(doc_auto_cfg))]
#![doc = include_str!("../README.md")]
#![deny(missing_docs)]
use std::{io, collections::HashMap};
use zeroize::Zeroizing;
@ -14,156 +15,41 @@ use ciphersuite::{
group::{Group, GroupEncoding},
Ciphersuite, Ristretto,
};
use dkg::{Participant, ThresholdCore, ThresholdKeys, evrf::*};
use dkg::{Participant, ThresholdKeys, evrf::*};
use log::info;
use serai_client::validator_sets::primitives::{Session, KeyPair};
use serai_validator_sets_primitives::Session;
use messages::key_gen::*;
use crate::{Get, DbTxn, Db, create_db, networks::Network};
use serai_db::{DbTxn, Db};
mod generators {
use core::any::{TypeId, Any};
use std::{
sync::{LazyLock, Mutex},
collections::HashMap,
};
use frost::dkg::evrf::*;
use serai_client::validator_sets::primitives::MAX_KEY_SHARES_PER_SET;
/// A cache of the generators used by the eVRF DKG.
///
/// This performs a lookup of the Ciphersuite to its generators. Since the Ciphersuite is a
/// generic, this takes advantage of `Any`. This static is isolated in a module to ensure
/// correctness can be evaluated solely by reviewing these few lines of code.
///
/// This is arguably over-engineered as of right now, as we only need generators for Ristretto
/// and N::Curve. By having this HashMap, we enable de-duplication of the Ristretto == N::Curve
/// case, and we automatically support the n-curve case (rather than hard-coding to the 2-curve
/// case).
static GENERATORS: LazyLock<Mutex<HashMap<TypeId, &'static (dyn Send + Sync + Any)>>> =
LazyLock::new(|| Mutex::new(HashMap::new()));
pub(crate) fn generators<C: EvrfCurve>() -> &'static EvrfGenerators<C> {
GENERATORS
.lock()
.unwrap()
.entry(TypeId::of::<C>())
.or_insert_with(|| {
// If we haven't prior needed generators for this Ciphersuite, generate new ones
Box::leak(Box::new(EvrfGenerators::<C>::new(
((MAX_KEY_SHARES_PER_SET * 2 / 3) + 1).try_into().unwrap(),
MAX_KEY_SHARES_PER_SET.try_into().unwrap(),
)))
})
.downcast_ref()
.unwrap()
}
}
mod generators;
use generators::generators;
#[derive(Debug)]
pub struct KeyConfirmed<C: Ciphersuite> {
pub substrate_keys: Vec<ThresholdKeys<Ristretto>>,
pub network_keys: Vec<ThresholdKeys<C>>,
}
mod db;
use db::{Params, Participations, KeyGenDb};
create_db!(
KeyGenDb {
ParamsDb: (session: &Session) -> (u16, Vec<[u8; 32]>, Vec<Vec<u8>>),
ParticipationDb: (session: &Session) -> (
HashMap<Participant, Vec<u8>>,
HashMap<Participant, Vec<u8>>,
),
// GeneratedKeysDb, KeysDb use `()` for their value as we manually serialize their values
// TODO: Don't do that
GeneratedKeysDb: (session: &Session) -> (),
// These do assume a key is only used once across sets, which holds true if the threshold is
// honest
// TODO: Remove this assumption
KeysDb: (network_key: &[u8]) -> (),
SessionDb: (network_key: &[u8]) -> Session,
NetworkKeyDb: (session: Session) -> Vec<u8>,
}
);
/// Parameters for a key generation.
pub trait KeyGenParams {
/// The ID for this instantiation.
const ID: &'static str;
impl GeneratedKeysDb {
#[allow(clippy::type_complexity)]
fn read_keys<N: Network>(
getter: &impl Get,
key: &[u8],
) -> Option<(Vec<u8>, (Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<N::Curve>>))> {
let keys_vec = getter.get(key)?;
let mut keys_ref: &[u8] = keys_vec.as_ref();
/// The curve used for the external network.
type ExternalNetworkCurve: EvrfCurve<
EmbeddedCurve: Ciphersuite<
G: ec_divisors::DivisorCurve<FieldElement = <Self::ExternalNetworkCurve as Ciphersuite>::F>,
>,
>;
let mut substrate_keys = vec![];
let mut network_keys = vec![];
while !keys_ref.is_empty() {
substrate_keys.push(ThresholdKeys::new(ThresholdCore::read(&mut keys_ref).unwrap()));
let mut these_network_keys = ThresholdKeys::new(ThresholdCore::read(&mut keys_ref).unwrap());
N::tweak_keys(&mut these_network_keys);
network_keys.push(these_network_keys);
}
Some((keys_vec, (substrate_keys, network_keys)))
}
/// Tweaks keys as necessary/beneficial.
fn tweak_keys(keys: &mut ThresholdKeys<Self::ExternalNetworkCurve>);
fn save_keys<N: Network>(
txn: &mut impl DbTxn,
session: &Session,
substrate_keys: &[ThresholdKeys<Ristretto>],
network_keys: &[ThresholdKeys<N::Curve>],
) {
let mut keys = Zeroizing::new(vec![]);
for (substrate_keys, network_keys) in substrate_keys.iter().zip(network_keys) {
keys.extend(substrate_keys.serialize().as_slice());
keys.extend(network_keys.serialize().as_slice());
}
txn.put(Self::key(session), keys);
}
}
impl KeysDb {
fn confirm_keys<N: Network>(
txn: &mut impl DbTxn,
session: Session,
key_pair: &KeyPair,
) -> (Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<N::Curve>>) {
let (keys_vec, keys) =
GeneratedKeysDb::read_keys::<N>(txn, &GeneratedKeysDb::key(&session)).unwrap();
assert_eq!(key_pair.0 .0, keys.0[0].group_key().to_bytes());
assert_eq!(
{
let network_key: &[u8] = key_pair.1.as_ref();
network_key
},
keys.1[0].group_key().to_bytes().as_ref(),
);
txn.put(Self::key(key_pair.1.as_ref()), keys_vec);
NetworkKeyDb::set(txn, session, &key_pair.1.clone().into_inner());
SessionDb::set(txn, key_pair.1.as_ref(), &session);
keys
}
#[allow(clippy::type_complexity)]
fn keys<N: Network>(
getter: &impl Get,
network_key: &<N::Curve as Ciphersuite>::G,
) -> Option<(Session, (Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<N::Curve>>))> {
let res =
GeneratedKeysDb::read_keys::<N>(getter, &Self::key(network_key.to_bytes().as_ref()))?.1;
assert_eq!(&res.1[0].group_key(), network_key);
Some((SessionDb::get(getter, network_key.to_bytes().as_ref()).unwrap(), res))
}
pub fn substrate_keys_by_session<N: Network>(
getter: &impl Get,
session: Session,
) -> Option<Vec<ThresholdKeys<Ristretto>>> {
let network_key = NetworkKeyDb::get(getter, session)?;
Some(GeneratedKeysDb::read_keys::<N>(getter, &Self::key(&network_key))?.1 .0)
/// Encode keys as optimal.
///
/// A default implementation is provided which calls the traditional `to_bytes`.
fn encode_key(key: <Self::ExternalNetworkCurve as Ciphersuite>::G) -> Vec<u8> {
key.to_bytes().as_ref().to_vec()
}
}
@ -242,49 +128,44 @@ fn coerce_keys<C: EvrfCurve>(
(keys, faulty)
}
/// An instance of the Serai key generation protocol.
#[derive(Debug)]
pub struct KeyGen<N: Network, D: Db> {
pub struct KeyGen<P: KeyGenParams, D: Db> {
db: D,
substrate_evrf_private_key:
Zeroizing<<<Ristretto as EvrfCurve>::EmbeddedCurve as Ciphersuite>::F>,
network_evrf_private_key: Zeroizing<<<N::Curve as EvrfCurve>::EmbeddedCurve as Ciphersuite>::F>,
network_evrf_private_key:
Zeroizing<<<P::ExternalNetworkCurve as EvrfCurve>::EmbeddedCurve as Ciphersuite>::F>,
}
impl<N: Network, D: Db> KeyGen<N, D> {
impl<P: KeyGenParams, D: Db> KeyGen<P, D> {
/// Create a new key generation instance.
#[allow(clippy::new_ret_no_self)]
pub fn new(
db: D,
substrate_evrf_private_key: Zeroizing<
<<Ristretto as EvrfCurve>::EmbeddedCurve as Ciphersuite>::F,
>,
network_evrf_private_key: Zeroizing<<<N::Curve as EvrfCurve>::EmbeddedCurve as Ciphersuite>::F>,
) -> KeyGen<N, D> {
network_evrf_private_key: Zeroizing<
<<P::ExternalNetworkCurve as EvrfCurve>::EmbeddedCurve as Ciphersuite>::F,
>,
) -> KeyGen<P, D> {
KeyGen { db, substrate_evrf_private_key, network_evrf_private_key }
}
pub fn in_set(&self, session: &Session) -> bool {
// We determine if we're in set using if we have the parameters for a session's key generation
// We only have these if we were told to generate a key for this session
ParamsDb::get(&self.db, session).is_some()
}
/// Fetch the key shares for a specific session.
#[allow(clippy::type_complexity)]
pub fn keys(
&self,
key: &<N::Curve as Ciphersuite>::G,
) -> Option<(Session, (Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<N::Curve>>))> {
// This is safe, despite not having a txn, since it's a static value
// It doesn't change over time/in relation to other operations
KeysDb::keys::<N>(&self.db, key)
}
pub fn substrate_keys_by_session(
pub fn key_shares(
&self,
session: Session,
) -> Option<Vec<ThresholdKeys<Ristretto>>> {
KeysDb::substrate_keys_by_session::<N>(&self.db, session)
) -> Option<(Vec<ThresholdKeys<Ristretto>>, Vec<ThresholdKeys<P::ExternalNetworkCurve>>)> {
// This is safe, despite not having a txn, since it's a static value
// It doesn't change over time/in relation to other operations
// It is solely set or unset
KeyGenDb::<P>::key_shares(&self.db, session)
}
/// Handle a message from the coordinator.
pub fn handle(
&mut self,
txn: &mut D::Transaction<'_>,
@ -292,10 +173,10 @@ impl<N: Network, D: Db> KeyGen<N, D> {
) -> Vec<ProcessorMessage> {
const SUBSTRATE_KEY_CONTEXT: &[u8] = b"substrate";
const NETWORK_KEY_CONTEXT: &[u8] = b"network";
fn context<N: Network>(session: Session, key_context: &[u8]) -> [u8; 32] {
fn context<P: KeyGenParams>(session: Session, key_context: &[u8]) -> [u8; 32] {
// TODO2: Also embed the chain ID/genesis block
let mut transcript = RecommendedTranscript::new(b"Serai eVRF Key Gen");
transcript.append_message(b"network", N::ID);
transcript.append_message(b"network", P::ID.as_bytes());
transcript.append_message(b"session", session.0.to_le_bytes());
transcript.append_message(b"key", key_context);
(&(&transcript.challenge(b"context"))[.. 32]).try_into().unwrap()
@ -308,64 +189,68 @@ impl<N: Network, D: Db> KeyGen<N, D> {
// Unzip the vector of eVRF keys
let substrate_evrf_public_keys =
evrf_public_keys.iter().map(|(key, _)| *key).collect::<Vec<_>>();
let (substrate_evrf_public_keys, mut faulty) =
coerce_keys::<Ristretto>(&substrate_evrf_public_keys);
let network_evrf_public_keys =
evrf_public_keys.into_iter().map(|(_, key)| key).collect::<Vec<_>>();
let mut participation = Vec::with_capacity(2048);
let mut faulty = HashSet::new();
let (network_evrf_public_keys, additional_faulty) =
coerce_keys::<P::ExternalNetworkCurve>(&network_evrf_public_keys);
faulty.extend(additional_faulty);
// Participate for both Substrate and the network
fn participate<C: EvrfCurve>(
context: [u8; 32],
threshold: u16,
evrf_public_keys: &[impl AsRef<[u8]>],
evrf_public_keys: &[<C::EmbeddedCurve as Ciphersuite>::G],
evrf_private_key: &Zeroizing<<C::EmbeddedCurve as Ciphersuite>::F>,
faulty: &mut HashSet<Participant>,
output: &mut impl io::Write,
) {
let (coerced_keys, faulty_is) = coerce_keys::<C>(evrf_public_keys);
for faulty_i in faulty_is {
faulty.insert(faulty_i);
}
let participation = EvrfDkg::<C>::participate(
&mut OsRng,
generators(),
context,
threshold,
&coerced_keys,
evrf_public_keys,
evrf_private_key,
);
participation.unwrap().write(output).unwrap();
}
let mut participation = Vec::with_capacity(2048);
participate::<Ristretto>(
context::<N>(session, SUBSTRATE_KEY_CONTEXT),
context::<P>(session, SUBSTRATE_KEY_CONTEXT),
threshold,
&substrate_evrf_public_keys,
&self.substrate_evrf_private_key,
&mut faulty,
&mut participation,
);
participate::<N::Curve>(
context::<N>(session, NETWORK_KEY_CONTEXT),
participate::<P::ExternalNetworkCurve>(
context::<P>(session, NETWORK_KEY_CONTEXT),
threshold,
&network_evrf_public_keys,
&self.network_evrf_private_key,
&mut faulty,
&mut participation,
);
// Save the params
ParamsDb::set(
KeyGenDb::<P>::set_params(
txn,
&session,
&(threshold, substrate_evrf_public_keys, network_evrf_public_keys),
session,
Params {
t: threshold,
n: substrate_evrf_public_keys
.len()
.try_into()
.expect("amount of keys exceeded the amount allowed during a DKG"),
substrate_evrf_public_keys,
network_evrf_public_keys,
},
);
// Send back our Participation and all faulty parties
let mut faulty = faulty.into_iter().collect::<Vec<_>>();
faulty.sort();
let mut res = Vec::with_capacity(faulty.len() + 1);
faulty.sort_unstable();
for faulty in faulty {
res.push(ProcessorMessage::Blame { session, participant: faulty });
}
@ -377,13 +262,8 @@ impl<N: Network, D: Db> KeyGen<N, D> {
CoordinatorMessage::Participation { session, participant, participation } => {
info!("received participation from {:?} for {:?}", participant, session);
let (threshold, substrate_evrf_public_keys, network_evrf_public_keys) =
ParamsDb::get(txn, &session).unwrap();
let n = substrate_evrf_public_keys
.len()
.try_into()
.expect("performing a key gen with more than u16::MAX participants");
let Params { t: threshold, n, substrate_evrf_public_keys, network_evrf_public_keys } =
KeyGenDb::<P>::params(txn, session).unwrap();
// Read these `Participation`s
// If they fail basic sanity checks, fail fast
@ -399,7 +279,8 @@ impl<N: Network, D: Db> KeyGen<N, D> {
return blame;
};
let len_at_network_participation_start_pos = participation.len();
let Ok(network_participation) = Participation::<N::Curve>::read(&mut participation, n)
let Ok(network_participation) =
Participation::<P::ExternalNetworkCurve>::read(&mut participation, n)
else {
return blame;
};
@ -413,16 +294,15 @@ impl<N: Network, D: Db> KeyGen<N, D> {
// If we've already generated these keys, we don't actually need to save these
// participations and continue. We solely have to verify them, as to identify malicious
// participants and prevent DoSs, before returning
if txn.get(GeneratedKeysDb::key(&session)).is_some() {
if self.key_shares(session).is_some() {
info!("already finished generating a key for {:?}", session);
match EvrfDkg::<Ristretto>::verify(
&mut OsRng,
generators(),
context::<N>(session, SUBSTRATE_KEY_CONTEXT),
context::<P>(session, SUBSTRATE_KEY_CONTEXT),
threshold,
// Ignores the list of participants who were faulty, as they were prior blamed
&coerce_keys::<Ristretto>(&substrate_evrf_public_keys).0,
&substrate_evrf_public_keys,
&HashMap::from([(participant, substrate_participation)]),
)
.unwrap()
@ -434,13 +314,12 @@ impl<N: Network, D: Db> KeyGen<N, D> {
}
}
match EvrfDkg::<N::Curve>::verify(
match EvrfDkg::<P::ExternalNetworkCurve>::verify(
&mut OsRng,
generators(),
context::<N>(session, NETWORK_KEY_CONTEXT),
context::<P>(session, NETWORK_KEY_CONTEXT),
threshold,
// Ignores the list of participants who were faulty, as they were prior blamed
&coerce_keys::<N::Curve>(&network_evrf_public_keys).0,
&network_evrf_public_keys,
&HashMap::from([(participant, network_participation)]),
)
.unwrap()
@ -467,17 +346,22 @@ impl<N: Network, D: Db> KeyGen<N, D> {
// Since these are valid `Participation`s, save them
let (mut substrate_participations, mut network_participations) =
ParticipationDb::get(txn, &session)
.unwrap_or((HashMap::with_capacity(1), HashMap::with_capacity(1)));
KeyGenDb::<P>::participations(txn, session).map_or_else(
|| (HashMap::with_capacity(1), HashMap::with_capacity(1)),
|p| (p.substrate_participations, p.network_participations),
);
assert!(
substrate_participations.insert(participant, substrate_participation).is_none() &&
network_participations.insert(participant, network_participation).is_none(),
"received participation for someone multiple times"
);
ParticipationDb::set(
KeyGenDb::<P>::set_participations(
txn,
&session,
&(substrate_participations.clone(), network_participations.clone()),
session,
&Participations {
substrate_participations: substrate_participations.clone(),
network_participations: network_participations.clone(),
},
);
// This block is taken from the eVRF DKG itself to evaluate the amount participating
@ -510,12 +394,12 @@ impl<N: Network, D: Db> KeyGen<N, D> {
}
// If we now have the threshold participating, verify their `Participation`s
fn verify_dkg<N: Network, C: EvrfCurve>(
fn verify_dkg<P: KeyGenParams, C: EvrfCurve>(
txn: &mut impl DbTxn,
session: Session,
true_if_substrate_false_if_network: bool,
threshold: u16,
evrf_public_keys: &[impl AsRef<[u8]>],
evrf_public_keys: &[<C::EmbeddedCurve as Ciphersuite>::G],
substrate_participations: &mut HashMap<Participant, Vec<u8>>,
network_participations: &mut HashMap<Participant, Vec<u8>>,
) -> Result<EvrfDkg<C>, Vec<ProcessorMessage>> {
@ -542,7 +426,7 @@ impl<N: Network, D: Db> KeyGen<N, D> {
match EvrfDkg::<C>::verify(
&mut OsRng,
generators(),
context::<N>(
context::<P>(
session,
if true_if_substrate_false_if_network {
SUBSTRATE_KEY_CONTEXT
@ -551,8 +435,7 @@ impl<N: Network, D: Db> KeyGen<N, D> {
},
),
threshold,
// Ignores the list of participants who were faulty, as they were prior blamed
&coerce_keys::<C>(evrf_public_keys).0,
evrf_public_keys,
&participations,
)
.unwrap()
@ -570,10 +453,13 @@ impl<N: Network, D: Db> KeyGen<N, D> {
blames.push(ProcessorMessage::Blame { session, participant });
}
// Since we removed `Participation`s, write the updated versions to the database
ParticipationDb::set(
KeyGenDb::<P>::set_participations(
txn,
&session,
&(substrate_participations.clone(), network_participations.clone()),
session,
&Participations {
substrate_participations: substrate_participations.clone(),
network_participations: network_participations.clone(),
},
);
Err(blames)?
}
@ -586,7 +472,7 @@ impl<N: Network, D: Db> KeyGen<N, D> {
}
}
let substrate_dkg = match verify_dkg::<N, Ristretto>(
let substrate_dkg = match verify_dkg::<P, Ristretto>(
txn,
session,
true,
@ -601,7 +487,7 @@ impl<N: Network, D: Db> KeyGen<N, D> {
Err(blames) => return blames,
};
let network_dkg = match verify_dkg::<N, N::Curve>(
let network_dkg = match verify_dkg::<P, P::ExternalNetworkCurve>(
txn,
session,
false,
@ -623,38 +509,17 @@ impl<N: Network, D: Db> KeyGen<N, D> {
let mut network_keys = network_dkg.keys(&self.network_evrf_private_key);
// Tweak the keys for the network
for network_keys in &mut network_keys {
N::tweak_keys(network_keys);
P::tweak_keys(network_keys);
}
GeneratedKeysDb::save_keys::<N>(txn, &session, &substrate_keys, &network_keys);
KeyGenDb::<P>::set_key_shares(txn, session, &substrate_keys, &network_keys);
// Since no one we verified was invalid, and we had the threshold, yield the new keys
vec![ProcessorMessage::GeneratedKeyPair {
session,
substrate_key: substrate_keys[0].group_key().to_bytes(),
// TODO: This can be made more efficient since tweaked keys may be a subset of keys
network_key: network_keys[0].group_key().to_bytes().as_ref().to_vec(),
network_key: P::encode_key(network_keys[0].group_key()),
}]
}
}
}
// This should only be called if we're participating, hence taking our instance
#[allow(clippy::unused_self)]
pub fn confirm(
&mut self,
txn: &mut D::Transaction<'_>,
session: Session,
key_pair: &KeyPair,
) -> KeyConfirmed<N::Curve> {
info!(
"Confirmed key pair {} {} for {:?}",
hex::encode(key_pair.0),
hex::encode(&key_pair.1),
session,
);
let (substrate_keys, network_keys) = KeysDb::confirm_keys::<N>(txn, session, key_pair);
KeyConfirmed { substrate_keys, network_keys }
}
}

2
processor/src/lib.rs
View file

@ -6,7 +6,7 @@ pub use plan::*;
mod db;
pub(crate) use db::*;
mod key_gen;
use serai_processor_key_gen as key_gen;
pub mod networks;
pub(crate) mod multisigs;

2
processor/src/main.rs
View file

@ -48,7 +48,7 @@ pub use db::*;
mod coordinator;
pub use coordinator::*;
mod key_gen;
use serai_processor_key_gen as key_gen;
use key_gen::{SessionDb, KeyConfirmed, KeyGen};
mod signer;