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AndrewWestbergAndrewWestberg
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feat: Validate conway block KES signatures
1 parent 36b4f01 commit 7d7da24

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+145
-32
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4 files changed

+145
-32
lines changed

‎ouroboros-praos/Cargo.toml

+4-4
Original file line numberDiff line numberDiff line change
@@ -6,14 +6,14 @@ edition = "2021"
66
[dependencies]
77
hex = "0.4"
88
ouroboros = { path = "../ouroboros" }
9-
pallas-crypto = { git = "https://github.com/txpipe/pallas", rev = "252714d58a93d58bf2cd7ada1156e3ace10a8298" }
10-
pallas-math = { git = "https://github.com/txpipe/pallas", rev = "252714d58a93d58bf2cd7ada1156e3ace10a8298" }
11-
pallas-primitives = { git = "https://github.com/txpipe/pallas", rev = "252714d58a93d58bf2cd7ada1156e3ace10a8298" }
9+
pallas-crypto = { git = "https://github.com/txpipe/pallas", rev = "7f988a16d412d4891408f99785372a4ef617984d" }
10+
pallas-math = { git = "https://github.com/txpipe/pallas", rev = "7f988a16d412d4891408f99785372a4ef617984d" }
11+
pallas-primitives = { git = "https://github.com/txpipe/pallas", rev = "7f988a16d412d4891408f99785372a4ef617984d" }
1212
tracing = "0.1"
1313

1414
[dev-dependencies]
1515
ctor = "0.2"
1616
insta = { version = "1.40.0", features = ["yaml"] }
1717
mockall = "0.13"
18-
pallas-traverse = { git = "https://github.com/txpipe/pallas", rev = "252714d58a93d58bf2cd7ada1156e3ace10a8298" }
18+
pallas-traverse = { git = "https://github.com/txpipe/pallas", rev = "7f988a16d412d4891408f99785372a4ef617984d" }
1919
tracing-subscriber = "0.3"

‎ouroboros-praos/src/consensus/mod.rs

+133-23
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,8 @@
1-
use ouroboros::ledger::{issuer_vkey_to_pool_id, PoolId, PoolInfo};
1+
use ouroboros::ledger::{issuer_vkey_to_pool_id, LedgerState, PoolId};
22
use ouroboros::validator::Validator;
33
use pallas_crypto::hash::{Hash, Hasher};
4+
use pallas_crypto::kes::{KesPublicKey, KesSignature};
5+
use pallas_crypto::key::ed25519::{PublicKey, Signature};
46
use pallas_crypto::vrf::{
57
VrfProof, VrfProofBytes, VrfProofHashBytes, VrfPublicKey, VrfPublicKeyBytes,
68
};
@@ -22,23 +24,23 @@ static CERTIFIED_NATURAL_MAX: LazyLock<FixedDecimal> = LazyLock::new(|| {
2224

2325
/// Validator for a block using praos consensus.
2426
pub struct BlockValidator<'b> {
25-
header: &'b babbage::Header,
26-
pool_info: &'b dyn PoolInfo,
27+
header: &'b babbage::MintedHeader<'b>,
28+
ledger_state: &'b dyn LedgerState,
2729
epoch_nonce: &'b Hash<32>,
2830
// c is the ln(1-active_slots_coeff). Usually ln(1-0.05)
2931
c: &'b FixedDecimal,
3032
}
3133

3234
impl<'b> BlockValidator<'b> {
3335
pub fn new(
34-
header: &'b babbage::Header,
35-
pool_info: &'b dyn PoolInfo,
36+
header: &'b babbage::MintedHeader,
37+
ledger_state: &'b dyn LedgerState,
3638
epoch_nonce: &'b Hash<32>,
3739
c: &'b FixedDecimal,
3840
) -> Self {
3941
Self {
4042
header,
41-
pool_info,
43+
ledger_state,
4244
epoch_nonce,
4345
c,
4446
}
@@ -62,7 +64,7 @@ impl<'b> BlockValidator<'b> {
6264
// Fail fast if the vrf key hash in the block does not match the ledger
6365
return false;
6466
}
65-
let sigma: FixedDecimal = match self.pool_info.sigma(&pool_id) {
67+
let sigma: FixedDecimal = match self.ledger_state.pool_id_to_sigma(&pool_id) {
6668
Ok(sigma) => {
6769
FixedDecimal::from(sigma.numerator) / FixedDecimal::from(sigma.denominator)
6870
}
@@ -116,7 +118,7 @@ impl<'b> BlockValidator<'b> {
116118
// Verify the VRF proof
117119
let vrf_proof = VrfProof::from(&block_vrf_proof);
118120
let vrf_vkey = VrfPublicKey::from(&vrf_vkey);
119-
match vrf_proof.verify(&vrf_vkey, vrf_input_seed.as_ref()) {
121+
let vrf_verified = match vrf_proof.verify(&vrf_vkey, vrf_input_seed.as_ref()) {
120122
Ok(proof_hash) => {
121123
if proof_hash.as_slice() != block_vrf_proof_hash.as_slice() {
122124
error!("VRF proof hash mismatch");
@@ -136,23 +138,122 @@ impl<'b> BlockValidator<'b> {
136138
} else {
137139
// The leader VRF output hash matches what was in the block
138140
// Now we need to check if the pool had enough sigma stake to produce this block
139-
if self.pool_meets_delegation_threshold(
141+
self.pool_meets_delegation_threshold(
140142
&sigma,
141143
absolute_slot,
142144
leader_vrf_output.as_slice(),
143-
) {
144-
// TODO: Validate the KES signature
145-
true
146-
} else {
147-
false
148-
}
145+
)
149146
}
150147
}
151148
}
152149
Err(error) => {
153150
error!("Could not verify block vrf: {}", error);
154151
false
155152
}
153+
};
154+
155+
if vrf_verified {
156+
// Verify the Operational Certificate signature
157+
let opcert_signature = match Signature::try_from(
158+
self.header
159+
.header_body
160+
.operational_cert
161+
.operational_cert_sigma
162+
.as_slice(),
163+
) {
164+
Ok(opcert_signature) => opcert_signature,
165+
Err(error) => {
166+
error!("Could not convert opcert_signature: {}", error);
167+
return false;
168+
}
169+
};
170+
171+
// The opcert message is a concatenation of the KES vkey, the counter, and the kes period
172+
let mut opcert_message = Vec::new();
173+
opcert_message.extend_from_slice(
174+
&self
175+
.header
176+
.header_body
177+
.operational_cert
178+
.operational_cert_hot_vkey,
179+
);
180+
opcert_message.extend_from_slice(
181+
&self
182+
.header
183+
.header_body
184+
.operational_cert
185+
.operational_cert_sequence_number
186+
.to_be_bytes(),
187+
);
188+
opcert_message.extend_from_slice(
189+
&self
190+
.header
191+
.header_body
192+
.operational_cert
193+
.operational_cert_kes_period
194+
.to_be_bytes(),
195+
);
196+
197+
let cold_pk = match PublicKey::try_from(issuer_vkey.as_slice()) {
198+
Ok(cold_pk) => cold_pk,
199+
Err(error) => {
200+
error!("Could not convert cold_pk: {}", error);
201+
return false;
202+
}
203+
};
204+
let opcert_verified = cold_pk.verify(&opcert_message, &opcert_signature);
205+
if opcert_verified {
206+
trace!("Operational Certificate signature verified");
207+
// Verify the KES signature
208+
let kes_pk = match KesPublicKey::from_bytes(
209+
&self
210+
.header
211+
.header_body
212+
.operational_cert
213+
.operational_cert_hot_vkey,
214+
) {
215+
Ok(kes_pk) => kes_pk,
216+
Err(error) => {
217+
error!("Could not convert kes_pk: {}", error);
218+
return false;
219+
}
220+
};
221+
222+
// calculate the right KES period to verify the signature
223+
let slot_kes_period = self.ledger_state.slot_to_kes_period(absolute_slot);
224+
let kes_period = (slot_kes_period
225+
- self
226+
.header
227+
.header_body
228+
.operational_cert
229+
.operational_cert_kes_period) as u32;
230+
trace!("kes_period: {}", kes_period);
231+
232+
// The header_body_cbor was signed by the KES private key. Verify this with the KES public key
233+
let header_body_cbor = self.header.header_body.raw_cbor();
234+
let kes_signature = match KesSignature::from_bytes(kes_signature) {
235+
Ok(kes_signature) => kes_signature,
236+
Err(error) => {
237+
error!("Could not convert kes_signature: {}", error);
238+
return false;
239+
}
240+
};
241+
match kes_signature.verify(kes_period, &kes_pk, header_body_cbor) {
242+
Ok(_) => {
243+
trace!("KES signature verified!");
244+
true
245+
}
246+
Err(error) => {
247+
error!("KES signature verification failed: {}", error);
248+
false
249+
}
250+
}
251+
} else {
252+
error!("Operational Certificate signature verification failed");
253+
false
254+
}
255+
} else {
256+
false
156257
}
157258
}
158259

@@ -205,7 +306,7 @@ impl<'b> BlockValidator<'b> {
205306
) -> bool {
206307
let vrf_vkey_hash: Hash<32> = Hasher::<256>::hash(vrf_vkey);
207308
trace!("block vrf_vkey_hash: {}", hex::encode(vrf_vkey_hash));
208-
let ledger_vrf_vkey_hash = match self.pool_info.vrf_vkey_hash(pool_id) {
309+
let ledger_vrf_vkey_hash = match self.ledger_state.vrf_vkey_hash(pool_id) {
209310
Ok(ledger_vrf_vkey_hash) => ledger_vrf_vkey_hash,
210311
Err(error) => {
211312
warn!("{:?} - {:?}", error, pool_id);
@@ -243,7 +344,7 @@ mod tests {
243344
use crate::consensus::BlockValidator;
244345
use ctor::ctor;
245346
use mockall::predicate::eq;
246-
use ouroboros::ledger::{MockPoolInfo, PoolId, PoolSigma};
347+
use ouroboros::ledger::{MockLedgerState, PoolId, PoolSigma};
247348
use ouroboros::validator::Validator;
248349
use pallas_crypto::hash::Hash;
249350
use pallas_math::math::{FixedDecimal, FixedPrecision};
@@ -252,7 +353,7 @@ mod tests {
252353
#[ctor]
253354
fn init() {
254355
// set rust log level to TRACE
255-
// std::env::set_var("RUST_LOG", "ouroboros-praos=trace");
356+
// std::env::set_var("RUST_LOG", "trace");
256357

257358
// initialize tracing crate
258359
tracing_subscriber::fmt::init();
@@ -299,22 +400,31 @@ mod tests {
299400
let babbage_header = multi_era_header.as_babbage().expect("Infallible");
300401
assert_eq!(babbage_header.header_body.slot, 134402628u64);
301402

302-
let mut pool_info = MockPoolInfo::new();
303-
pool_info
304-
.expect_sigma()
403+
let mut ledger_state = MockLedgerState::new();
404+
ledger_state
405+
.expect_pool_id_to_sigma()
305406
.with(eq(pool_id))
306407
.returning(move |_| {
307408
Ok(PoolSigma {
308409
numerator,
309410
denominator,
310411
})
311412
});
312-
pool_info
413+
ledger_state
313414
.expect_vrf_vkey_hash()
314415
.with(eq(pool_id))
315416
.returning(move |_| Ok(vrf_vkey_hash));
417+
ledger_state
418+
.expect_slot_to_kes_period()
419+
.returning(move |slot| {
420+
// hardcode some values from shelley-genesis.json for the mock implementation
421+
let slot_length: u64 = 1; // from shelley-genesis.json (1 second)
422+
let slots_per_kes_period: u64 = 129600; // from shelley-genesis.json (1.5 days in seconds)
423+
slot / (slots_per_kes_period * slot_length)
424+
});
316425

317-
let block_validator = BlockValidator::new(babbage_header, &pool_info, &epoch_nonce, &c);
426+
let block_validator =
427+
BlockValidator::new(babbage_header, &ledger_state, &epoch_nonce, &c);
318428
assert_eq!(block_validator.validate(), expected);
319429
}
320430
}

‎ouroboros/Cargo.toml

+2-2
Original file line numberDiff line numberDiff line change
@@ -6,8 +6,8 @@ edition = "2021"
66
[dependencies]
77
hex = "0.4.3"
88
mockall = "0.13"
9-
pallas-codec = { git = "https://github.com/txpipe/pallas", rev = "252714d58a93d58bf2cd7ada1156e3ace10a8298" }
10-
pallas-crypto = { git = "https://github.com/txpipe/pallas", rev = "252714d58a93d58bf2cd7ada1156e3ace10a8298" }
9+
pallas-codec = { git = "https://github.com/txpipe/pallas", rev = "7f988a16d412d4891408f99785372a4ef617984d" }
10+
pallas-crypto = { git = "https://github.com/txpipe/pallas", rev = "7f988a16d412d4891408f99785372a4ef617984d" }
1111
thiserror = "1.0"
1212

1313
[dev-dependencies]

‎ouroboros/src/ledger/mod.rs

+6-3
Original file line numberDiff line numberDiff line change
@@ -20,16 +20,19 @@ pub struct PoolSigma {
2020
pub denominator: u64,
2121
}
2222

23-
/// The pool info trait provides a lookup mechanism for pool data. This is sourced from the ledger
23+
/// The LedgerState trait provides a lookup mechanism for various information sourced from the ledger
2424
#[automock]
25-
pub trait PoolInfo: Send + Sync {
25+
pub trait LedgerState: Send + Sync {
2626
/// Performs a lookup of a pool_id to its sigma value. This usually represents a different set of
2727
/// sigma snapshot data depending on whether we need to look up the pool_id in the current epoch
2828
/// or in the future.
29-
fn sigma(&self, pool_id: &PoolId) -> Result<PoolSigma, Error>;
29+
fn pool_id_to_sigma(&self, pool_id: &PoolId) -> Result<PoolSigma, Error>;
3030

3131
/// Hashes the vrf vkey of a pool.
3232
fn vrf_vkey_hash(&self, pool_id: &PoolId) -> Result<Hash<32>, Error>;
33+
34+
/// Calculate the KES period given an absolute slot and some shelley-genesis values
35+
fn slot_to_kes_period(&self, slot: u64) -> u64;
3336
}
3437

3538
/// The node's cold vkey is hashed with blake2b224 to create the pool id

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