From 9feb687f08ea59d825c9f0af553e975decc56632 Mon Sep 17 00:00:00 2001
From: Alon Frydberg <alonf@starkware.co>
Date: Thu, 23 Jan 2025 10:39:15 +0200
Subject: [PATCH] Add security_bites function to PcsConfig

---
 crates/prover/src/core/fri.rs           |  4 ++++
 crates/prover/src/core/pcs/mod.rs       | 19 +++++++++++++++++++
 crates/prover/src/examples/blake/air.rs |  4 +++-
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/crates/prover/src/core/fri.rs b/crates/prover/src/core/fri.rs
index 30ad38aac..a80fcf234 100644
--- a/crates/prover/src/core/fri.rs
+++ b/crates/prover/src/core/fri.rs
@@ -72,6 +72,10 @@ impl FriConfig {
     const fn last_layer_domain_size(&self) -> usize {
         1 << (self.log_last_layer_degree_bound + self.log_blowup_factor)
     }
+
+    pub const fn security_bits(&self) -> u32 {
+        self.log_blowup_factor * self.n_queries as u32
+    }
 }
 
 pub trait FriOps: ColumnOps<BaseField> + PolyOps + Sized + ColumnOps<SecureField> {
diff --git a/crates/prover/src/core/pcs/mod.rs b/crates/prover/src/core/pcs/mod.rs
index ab415dbae..1b7167ba8 100644
--- a/crates/prover/src/core/pcs/mod.rs
+++ b/crates/prover/src/core/pcs/mod.rs
@@ -33,6 +33,7 @@ pub struct PcsConfig {
     pub pow_bits: u32,
     pub fri_config: FriConfig,
 }
+
 impl Default for PcsConfig {
     fn default() -> Self {
         Self {
@@ -41,3 +42,21 @@ impl Default for PcsConfig {
         }
     }
 }
+
+impl PcsConfig {
+    pub const fn security_bits(&self) -> u32 {
+        self.pow_bits + self.fri_config.security_bits()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_security_bits() {
+        let config = super::PcsConfig {
+            pow_bits: 26,
+            fri_config: super::FriConfig::new(1, 1, 70),
+        };
+        assert!(config.security_bits() == 96);
+    }
+}
diff --git a/crates/prover/src/examples/blake/air.rs b/crates/prover/src/examples/blake/air.rs
index e7be746b8..6f58bc615 100644
--- a/crates/prover/src/examples/blake/air.rs
+++ b/crates/prover/src/examples/blake/air.rs
@@ -509,8 +509,10 @@ pub fn verify_blake<MC: MerkleChannel>(
         stark_proof,
     }: BlakeProof<MC::H>,
 ) -> Result<(), VerificationError> {
-    let channel = &mut MC::C::default();
     // TODO(alonf): Consider mixing the config into the channel.
+    let channel = &mut MC::C::default();
+    const REQUIRED_SECURITY_BITS: u32 = 5;
+    assert!(stark_proof.config.security_bits() >= REQUIRED_SECURITY_BITS);
     let commitment_scheme = &mut CommitmentSchemeVerifier::<MC>::new(stark_proof.config);
 
     let log_sizes = stmt0.log_sizes();