make the range of the supported rate values (in WHIR) = 1/2, 1/4, 1/8, 1/16 more explicit

Author: TomWambsgans

crates/backend/fiat-shamir/src/errors.rs

@@ -23,14 +23,11 @@ use std::{error::Error, fmt::Display};
 /// An error happened when creating or verifying a proof.
 #[derive(Debug, Clone)]
 pub enum ProofError {
-    /// Signals the verification equation has failed.
     InvalidProof,
-    /// Verifier is asking more data than what was provided in the transcript.
     ExceededTranscript,
-    /// Invalid Pow Grinding
     InvalidGrindingWitness,
-    /// Invalid Padding in the transcript
     InvalidPadding,
+    InvalidRate,
 }
 
 /// The result type when trying to prove or verify a proof using Fiat-Shamir.
@@ -43,6 +40,10 @@ impl Display for ProofError {
             Self::ExceededTranscript => write!(f, "Verifier exceeded transcript length"),
             Self::InvalidGrindingWitness => write!(f, "Invalid grinding witness"),
             Self::InvalidPadding => write!(f, "Invalid padding in the transcript"),
+            Self::InvalidRate => write!(
+                f,
+                "LeanVM supports rate 1/2, 1/4, 1/8 and 1/16 (log_inv_rate in {{1, 2, 3, 4}})"
+            ),
         }
     }
 }

crates/lean_prover/src/lib.rs

@@ -1,7 +1,7 @@
 #![cfg_attr(not(test), allow(unused_crate_dependencies))]
 
 use backend::*;
-use lean_vm::{EF, F};
+use lean_vm::{EF, F, MAX_WHIR_LOG_INV_RATE, MIN_WHIR_LOG_INV_RATE};
 use utils::*;
 
 mod trace_gen;
@@ -44,6 +44,14 @@ pub fn default_whir_config(starting_log_inv_rate: usize) -> WhirConfigBuilder {
     }
 }
 
+pub(crate) fn check_rate(log_inv_rate: usize) -> Result<(), ProofError> {
+    if (MIN_WHIR_LOG_INV_RATE..=MAX_WHIR_LOG_INV_RATE).contains(&log_inv_rate) {
+        Ok(())
+    } else {
+        Err(ProofError::InvalidRate)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use backend::default_koalabear_poseidon2_16;

crates/lean_prover/src/prove_execution.rs

@@ -22,6 +22,7 @@ pub fn prove_execution(
     whir_config: &WhirConfigBuilder,
     vm_profiler: bool,
 ) -> ExecutionProof {
+    check_rate(whir_config.starting_log_inv_rate).unwrap();
     let ExecutionTrace {
         traces,
         public_memory_size,

crates/lean_prover/src/verify_execution.rs

@@ -32,9 +32,7 @@ pub fn verify_execution(
         return Err(ProofError::InvalidProof);
     }
     let table_n_vars: BTreeMap<Table, VarCount> = (0..N_TABLES).map(|i| (ALL_TABLES[i], dims[i + 3])).collect();
-    if !(MIN_WHIR_LOG_INV_RATE..=MAX_WHIR_LOG_INV_RATE).contains(&log_inv_rate) {
-        return Err(ProofError::InvalidProof);
-    }
+    check_rate(log_inv_rate)?;
     let whir_config = default_whir_config(log_inv_rate);
     for (table, &n_vars) in &table_n_vars {
         if n_vars < MIN_LOG_N_ROWS_PER_TABLE {