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Merge pull request #5689 from oasisprotocol/peternose/trivial/churp-r…
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…ename-player

secret-sharing/src/churp: Rename player to shareholder
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@peternose
peternose authored May 8, 2024
2 parents fe32bd2 + 3ede60d commit f328068
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Showing 9 changed files with 308 additions and 311 deletions.
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4 changes: 2 additions & 2 deletions go/keymanager/churp/status.go
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Original file line number Diff line number Diff line change
Expand Up @@ -176,8 +176,8 @@ func (s *Status) MinApplicants() int {
switch s.HandoffKind() {
case HandoffKindDealingPhase:
// The number of nodes must be at least t+2, ensuring that even if
// t Byzantine dealers reveal their secret, an honest player cannot
// compute the combined bivariate polynomial.
// t Byzantine dealers reveal their secret, an honest shareholder
// cannot compute the combined bivariate polynomial.
return max(t+e+1, t+2)
case HandoffKindCommitteeUnchanged:
return t + e + 1
Expand Down
8 changes: 4 additions & 4 deletions keymanager/src/churp/errors.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -43,10 +43,6 @@ pub enum Error {
NotAuthorized,
#[error("not in committee")]
NotInCommittee,
#[error("player mismatch")]
PlayerMismatch,
#[error("player not found")]
PlayerNotFound,
#[error("point decoding failed")]
PointDecodingFailed,
#[error("policy rollback")]
Expand All @@ -55,6 +51,10 @@ pub enum Error {
PolynomialDecodingFailed,
#[error("runtime mismatch")]
RuntimeMismatch,
#[error("shareholder mismatch")]
ShareholderMismatch,
#[error("shareholder not found")]
ShareholderNotFound,
#[error("status not published")]
StatusNotPublished,
#[error("verification matrix decoding failed")]
Expand Down
137 changes: 70 additions & 67 deletions keymanager/src/churp/handler.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,7 @@ use oasis_core_runtime::{
};

use secret_sharing::{
churp::{Dealer, Handoff, HandoffKind, Player, ShareholderId},
churp::{Dealer, Handoff, HandoffKind, Shareholder, ShareholderId},
suites::{p384, Suite},
vss::{
matrix::VerificationMatrix,
Expand Down Expand Up @@ -108,9 +108,9 @@ pub struct Churp {
#[cfg_attr(not(target_env = "sgx"), allow(unused))]
registry_state: RegistryState,

/// Players with secret shares for the last successfully completed handoff,
/// one per scheme.
players: Mutex<HashMap<u8, HandoffData>>,
/// Shareholders with secret shares for the last successfully completed
/// handoff, one per scheme.
shareholders: Mutex<HashMap<u8, HandoffData>>,
/// Dealers of bivariate shares for the next handoff, one per scheme.
dealers: Mutex<HashMap<u8, HandoffData>>,
/// Next handoffs, limited to one per scheme.
Expand Down Expand Up @@ -138,7 +138,7 @@ impl Churp {
let churp_state = ChurpState::new(consensus_verifier.clone());
let registry_state = RegistryState::new(consensus_verifier.clone());

let players = Mutex::new(HashMap::new());
let shareholders = Mutex::new(HashMap::new());
let dealers = Mutex::new(HashMap::new());
let handoffs = Mutex::new(HashMap::new());

Expand All @@ -153,7 +153,7 @@ impl Churp {
consensus_verifier,
storage,
beacon_state,
players,
shareholders,
churp_state,
registry_state,
dealers,
Expand Down Expand Up @@ -191,10 +191,12 @@ impl Churp {
/// of the matrix should always be verified against the consensus layer.
pub fn verification_matrix(&self, req: &QueryRequest) -> Result<Vec<u8>> {
let status = self.verify_last_handoff(req.id, req.runtime_id, req.epoch)?;
let player = match status.suite_id {
SuiteId::NistP384Sha3_384 => self.get_player::<p384::Sha3_384>(req.id, req.epoch)?,
let shareholder = match status.suite_id {
SuiteId::NistP384Sha3_384 => {
self.get_shareholder::<p384::Sha3_384>(req.id, req.epoch)?
}
};
let vm = player.verification_matrix().to_bytes();
let vm = shareholder.verification_matrix().to_bytes();

Ok(vm)
}
Expand Down Expand Up @@ -253,8 +255,8 @@ impl Churp {
S: Suite + 'static,
{
let id = ShareholderId(node_id.0);
let player = self.get_player::<S>(status.id, status.handoff)?;
let point = player.switch_point(id)?;
let shareholder = self.get_shareholder::<S>(status.id, status.handoff)?;
let point = shareholder.switch_point(id)?;
let point = scalar_to_bytes(&point);

Ok(point)
Expand Down Expand Up @@ -319,8 +321,8 @@ impl Churp {
{
let id = ShareholderId(node_id.0);
let handoff = self.get_handoff::<S>(status.id, status.next_handoff)?;
let player = handoff.get_reduced_player()?;
let point = player.switch_point(id)?;
let shareholder = handoff.get_reduced_shareholder()?;
let point = shareholder.switch_point(id)?;
let point = scalar_to_bytes(&point);

Ok(point)
Expand Down Expand Up @@ -541,12 +543,12 @@ impl Churp {

// Fetch from the host node.
if node_id == self.node_id {
let player = self.get_player::<S>(status.id, status.handoff)?;
let point = player.switch_point(id)?;
let shareholder = self.get_shareholder::<S>(status.id, status.handoff)?;
let point = shareholder.switch_point(id)?;

if handoff.needs_verification_matrix()? {
// Local verification matrix is trusted.
let vm = player.verification_matrix().clone();
let vm = shareholder.verification_matrix().clone();
handoff.set_verification_matrix(vm)?;
}

Expand Down Expand Up @@ -644,8 +646,8 @@ impl Churp {

// Fetch from the host node.
if node_id == self.node_id {
let player = handoff.get_reduced_player()?;
let point = player.switch_point(id)?;
let shareholder = handoff.get_reduced_shareholder()?;
let point = shareholder.switch_point(id)?;

return handoff.add_full_share_distribution_switch_point(id, point);
}
Expand Down Expand Up @@ -772,15 +774,15 @@ impl Churp {
S: Suite + 'static,
{
let handoff = self.get_handoff::<S>(status.id, status.next_handoff)?;
let player = handoff.get_full_player()?;
let share = player.secret_share();
let shareholder = handoff.get_full_shareholder()?;
let share = shareholder.secret_share();

// Before overwriting the next secret share, make sure it was copied
// and used to construct the last player.
// and used to construct the last shareholder.
let _ = self
.get_player::<S>(status.id, status.handoff)
.get_shareholder::<S>(status.id, status.handoff)
.map(Some)
.or_else(|err| ignore_error(err, Error::PlayerNotFound))?; // Ignore if we don't have the correct share.
.or_else(|err| ignore_error(err, Error::ShareholderNotFound))?; // Ignore if we don't have the correct share.

// Always persist the secret share before sending confirmation.
self.storage
Expand Down Expand Up @@ -808,8 +810,9 @@ impl Churp {
}

/// Finalizes the specified scheme by cleaning up obsolete dealers,
/// handoffs, and players. If the handoff was just completed, the player
/// is made available, and its share is persisted to the local storage.
/// handoffs, and shareholders. If the handoff was just completed,
/// the shareholder is made available, and its share is persisted
/// to the local storage.
pub fn finalize(&self, req: &HandoffRequest) -> Result<()> {
let status = self.verify_last_handoff(req.id, req.runtime_id, req.epoch)?;

Expand All @@ -822,7 +825,7 @@ impl Churp {
where
S: Suite + 'static,
{
// Move the player if the handoff was completed.
// Move the shareholder if the handoff was completed.
let handoff = self.get_handoff::<S>(status.id, status.handoff);
let handoff = match handoff {
Ok(handoff) => Some(handoff),
Expand All @@ -832,16 +835,16 @@ impl Churp {
},
};
if let Some(handoff) = handoff {
let player = handoff.get_full_player()?;
let share = player.secret_share();
let shareholder = handoff.get_full_shareholder()?;
let share = shareholder.secret_share();
self.storage
.store_secret_share(share, status.id, status.handoff)?;
self.add_player(player, status.id, status.handoff);
self.add_shareholder(shareholder, status.id, status.handoff);
}

// Cleanup.
let max_epoch = status.handoff.saturating_sub(1);
self.remove_player(status.id, max_epoch);
self.remove_shareholder(status.id, max_epoch);

let max_epoch = status.next_handoff.saturating_sub(1);
self.remove_dealer(status.id, max_epoch);
Expand All @@ -850,35 +853,35 @@ impl Churp {
Ok(())
}

/// Returns the player for the specified scheme and handoff epoch.
fn get_player<S>(&self, churp_id: u8, epoch: EpochTime) -> Result<Arc<Player<S>>>
/// Returns the shareholder for the specified scheme and handoff epoch.
fn get_shareholder<S>(&self, churp_id: u8, epoch: EpochTime) -> Result<Arc<Shareholder<S>>>
where
S: Suite + 'static,
{
// Check the memory first. Make sure to lock the new players so that we
// don't create two players for the same handoff.
let mut players = self.players.lock().unwrap();
// Check the memory first. Make sure to lock the new shareholders
// so that we don't create two shareholders for the same handoff.
let mut shareholders = self.shareholders.lock().unwrap();

if let Some(data) = players.get(&churp_id) {
if let Some(data) = shareholders.get(&churp_id) {
match epoch.cmp(&data.epoch) {
cmp::Ordering::Less => return Err(Error::InvalidHandoff.into()),
cmp::Ordering::Equal => {
// Downcasting should never fail because the consensus ensures that
// the group ID cannot change.
let player = data
// Downcasting should never fail because the consensus
// ensures that the suite ID cannot change.
let shareholder = data
.object
.clone()
.downcast::<Player<S>>()
.or(Err(Error::PlayerMismatch))?;
.downcast::<Shareholder<S>>()
.or(Err(Error::ShareholderMismatch))?;

return Ok(player);
return Ok(shareholder);
}
cmp::Ordering::Greater => (),
}
}

// Fetch player's secret share from the local storage and use it to
// restore the internal state upon restarts, unless a malicious
// Fetch shareholder's secret share from the local storage and use it
// to restore the internal state upon restarts, unless a malicious
// host has cleared the storage.
let share = self
.storage
Expand All @@ -903,44 +906,44 @@ impl Churp {
share
}
};
let share = share.ok_or(Error::PlayerNotFound)?;
let share = share.ok_or(Error::ShareholderNotFound)?;

// Create a new player.
let player = Arc::new(Player::from(share));
// Create a new shareholder.
let shareholder = Arc::new(Shareholder::from(share));
let data = HandoffData {
epoch,
object: player.clone(),
object: shareholder.clone(),
};
players.insert(churp_id, data);
shareholders.insert(churp_id, data);

Ok(player)
Ok(shareholder)
}

/// Adds a player for the specified scheme and handoff epoch.
fn add_player<S>(&self, player: Arc<Player<S>>, churp_id: u8, epoch: EpochTime)
/// Adds a shareholder for the specified scheme and handoff epoch.
fn add_shareholder<S>(&self, shareholder: Arc<Shareholder<S>>, churp_id: u8, epoch: EpochTime)
where
S: Suite + 'static,
{
let mut players = self.players.lock().unwrap();
let mut shareholders = self.shareholders.lock().unwrap();

if let Some(data) = players.get(&churp_id) {
if let Some(data) = shareholders.get(&churp_id) {
if epoch <= data.epoch {
return;
}
}

let data = HandoffData {
epoch,
object: player,
object: shareholder,
};
players.insert(churp_id, data);
shareholders.insert(churp_id, data);
}

/// Removes player for the specified scheme if the player belongs
/// Removes shareholder for the specified scheme if the shareholder belongs
/// to a handoff that happened at or before the given epoch.
fn remove_player(&self, churp_id: u8, max_epoch: EpochTime) {
let mut players = self.players.lock().unwrap();
let data = match players.get(&churp_id) {
fn remove_shareholder(&self, churp_id: u8, max_epoch: EpochTime) {
let mut shareholders = self.shareholders.lock().unwrap();
let data = match shareholders.get(&churp_id) {
Some(data) => data,
None => return,
};
Expand All @@ -949,7 +952,7 @@ impl Churp {
return;
}

players.remove(&churp_id);
shareholders.remove(&churp_id);
}

/// Returns the dealer for the specified scheme and handoff epoch.
Expand Down Expand Up @@ -993,8 +996,8 @@ impl Churp {
match epoch.cmp(&data.epoch) {
cmp::Ordering::Less => return Err(Error::InvalidHandoff.into()),
cmp::Ordering::Equal => {
// Downcasting should never fail because the consensus ensures that
// the group ID cannot change.
// Downcasting should never fail because the consensus
// ensures that the suite ID cannot change.
let dealer = data
.object
.clone()
Expand Down Expand Up @@ -1107,8 +1110,8 @@ impl Churp {
match epoch.cmp(&data.epoch) {
cmp::Ordering::Less => return Err(Error::InvalidHandoff.into()),
cmp::Ordering::Equal => {
// Downcasting should never fail because the consensus ensures that
// the group ID cannot change.
// Downcasting should never fail because the consensus
// ensures that the suite ID cannot change.
let handoff = data
.object
.clone()
Expand Down Expand Up @@ -1137,8 +1140,8 @@ impl Churp {
let handoff = Handoff::new(threshold, me, shareholders, kind)?;

if kind == HandoffKind::CommitteeUnchanged {
let player = self.get_player(churp_id, status.handoff)?;
handoff.set_player(player)?;
let shareholder = self.get_shareholder(churp_id, status.handoff)?;
handoff.set_shareholder(shareholder)?;
}

let handoff = Arc::new(handoff);
Expand Down
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