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// Copyright (c) 2019-2026 Provable Inc.
// This file is part of the snarkVM library.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at:
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use super::*;
impl<N: Network> StatePath<N> {
/// Checks if the state path is valid.
///
/// # Parameters
/// - `local_state_root` is the local transaction root for the current execution.
/// - `is_global` is a boolean indicating whether this is a global or local state root.
///
/// # Diagram
/// The `[[ ]]` notation is used to denote public inputs.
/// ```ignore
///
/// [[ global_state_root ]]
/// |
/// block_path
/// |
/// block_hash := Hash( previous_block_hash || header_root )
/// |
/// header_path
/// |
/// header_leaf
/// |
/// transactions_path [[ local_state_root ]]
/// | |
/// (true) ------ is_global ------ (false)
/// |
/// transaction_id
/// |
/// transaction_path
/// |
/// transaction_leaf
/// |
/// transition_id := Hash( transition_root || tcm )
/// |
/// transition_path
/// |
/// transition_leaf
/// ```
pub fn verify(&self, is_global: bool, local_state_root: Field<N>) -> Result<()> {
// Ensure the transition leaf variant is 3 (Input::Record).
ensure!(self.transition_leaf.variant() == 3, "Transition leaf variant must be 3 (Input::Record)");
// Ensure the transition path is valid.
ensure!(
N::verify_merkle_path_bhp(&self.transition_path, &self.transition_root, &self.transition_leaf.to_bits_le()),
"'{}' (an input or output ID) does not belong to '{}' (a function or transition)",
self.transition_leaf.id(),
self.transaction_leaf.id()
);
// Ensure the transaction leaf is correct.
ensure!(
*self.transaction_leaf.id() == *N::hash_bhp512(&(*self.transition_root, self.tcm).to_bits_le())?,
"Transaction leaf id '{}' is incorrect. Double-check the tcm and transition root.",
self.transaction_leaf.id()
);
// Ensure the transaction leaf variant is 1 (Transaction::Execution).
ensure!(self.transaction_leaf.variant() == 1, "Transaction leaf variant must be 1 (Transaction::Execution)");
// Ensure the transaction path is valid.
ensure!(
N::verify_merkle_path_bhp(
&self.transaction_path,
&self.transaction_id,
&self.transaction_leaf.to_bits_le()
),
"'{}' (a function or transition) does not belong to transaction '{}'",
self.transaction_leaf.id(),
self.transaction_id
);
if is_global {
// Ensure the header leaf index is 1 (Header::transactions_root).
ensure!(self.header_leaf.index() == 1, "Header leaf index must be 1 (Header::transactions_root)");
// Ensure the transactions path is valid.
ensure!(
N::verify_merkle_path_bhp(
&self.transactions_path,
&self.header_leaf.id(),
&self.transaction_id.to_bits_le()
),
"Transaction '{}' does not belong to '{}' (a header leaf)",
self.transaction_id,
self.header_leaf
);
// Ensure the header path is valid.
ensure!(
N::verify_merkle_path_bhp(&self.header_path, &self.header_root, &self.header_leaf.to_bits_le()),
"'{}' (a header leaf) does not belong to '{}' (a block header)",
self.header_leaf,
self.block_hash
);
// Ensure the block hash is correct.
ensure!(
*self.block_hash == N::hash_bhp1024(&to_bits_le![(*self.previous_block_hash), self.header_root])?,
"Block hash '{}' is incorrect. Double-check the previous block hash and block header root.",
self.block_hash
);
// Ensure the global state root is correct.
ensure!(
N::verify_merkle_path_bhp(&self.block_path, &self.global_state_root, &self.block_hash.to_bits_le()),
"'{}' (a block hash) does not belong to '{}' (a global state root)",
self.block_hash,
self.global_state_root
);
} else {
// Ensure the local state root is correct.
ensure!(
*self.transaction_id == local_state_root,
"'{}' (a decoded transaction ID) does not match the '{local_state_root}' (a local state root)",
*self.transaction_id
);
}
Ok(())
}
}
#[cfg(test)]
mod tests {
use super::*;
use snarkvm_console_network::{MainnetV0, prelude::TestRng};
type CurrentNetwork = MainnetV0;
const ITERATIONS: usize = 100;
#[test]
fn test_verify_global() {
let rng = &mut TestRng::default();
for _ in 0..ITERATIONS {
// Sample the state path.
let state_path =
crate::state_path::test_helpers::sample_global_state_path::<CurrentNetwork>(None, rng).unwrap();
// Sample the local state root.
let local_state_root = Field::rand(rng);
// Ensure the state path is valid.
state_path.verify(true, local_state_root).unwrap();
// Ensure the state path is *not* valid for a random local state root.
state_path.verify(false, local_state_root).unwrap_err();
}
}
#[test]
fn test_verify_local() {
let rng = &mut TestRng::default();
for _ in 0..ITERATIONS {
// Sample the state path.
let state_path =
crate::state_path::test_helpers::sample_local_state_path::<CurrentNetwork>(None, rng).unwrap();
// Retrieve the local state root.
let local_state_root = **state_path.transaction_id();
// Ensure the state path is valid.
state_path.verify(false, local_state_root).unwrap();
// Ensure the state path does *not* match a random local state root.
state_path.verify(false, Field::rand(rng)).unwrap_err();
// Ensure the state path does *not* match to the random global state root.
state_path.verify(true, local_state_root).unwrap_err();
// Ensure the state path does *not* match to the random global state root.
state_path.verify(true, Field::rand(rng)).unwrap_err();
}
}
#[test]
fn test_verify_new_local() {
let rng = &mut TestRng::default();
for _ in 0..ITERATIONS {
// Sample the state path.
let state_path =
crate::state_path::test_helpers::sample_local_state_path::<CurrentNetwork>(None, rng).unwrap();
// Initialize the state path using `new_local`.
let new_local_state_path = StatePath::new_local(
state_path.global_state_root(),
*state_path.transaction_id(),
state_path.transaction_path().clone(),
*state_path.transaction_leaf(),
*state_path.transition_root(),
*state_path.tcm(),
state_path.transition_path().clone(),
*state_path.transition_leaf(),
)
.unwrap();
// Retrieve the local state root.
let local_state_root = **new_local_state_path.transaction_id();
// Ensure the state path is valid.
new_local_state_path.verify(false, local_state_root).unwrap();
// Ensure the state path does *not* match a random local state root.
new_local_state_path.verify(false, Field::rand(rng)).unwrap_err();
// Ensure the state path does *not* match to the random global state root.
new_local_state_path.verify(true, local_state_root).unwrap_err();
// Ensure the state path does *not* match to the random global state root.
new_local_state_path.verify(true, Field::rand(rng)).unwrap_err();
}
}
}