From 643057a07c7c6aa055d85fff0f5db79f44d1d082 Mon Sep 17 00:00:00 2001
From: VolodymyrBg <aqdrgg19@gmail.com>
Date: Mon, 9 Feb 2026 10:11:59 +0200
Subject: [PATCH 1/2] perf: remove redundant Felt252 bytes roundtrip in
 SignatureBuiltinRunner

---
 vm/src/vm/runners/builtin_runner/signature.rs | 38 ++++---------------
 1 file changed, 7 insertions(+), 31 deletions(-)

diff --git a/vm/src/vm/runners/builtin_runner/signature.rs b/vm/src/vm/runners/builtin_runner/signature.rs
index bdd7a95a0c..6bd529596a 100644
--- a/vm/src/vm/runners/builtin_runner/signature.rs
+++ b/vm/src/vm/runners/builtin_runner/signature.rs
@@ -61,17 +61,7 @@ impl SignatureBuiltinRunner {
         relocatable: Relocatable,
         (r, s): &(Felt252, Felt252),
     ) -> Result<(), MemoryError> {
-        let r_be_bytes = r.to_bytes_be();
-        let s_be_bytes = s.to_bytes_be();
-        let (r_felt, s_felt) = (
-            Felt252::from_bytes_be(&r_be_bytes),
-            Felt252::from_bytes_be(&s_be_bytes),
-        );
-
-        let signature = Signature {
-            r: r_felt,
-            s: s_felt,
-        };
+        let signature = Signature { r: *r, s: *s };
 
         self.signatures
             .borrow_mut()
@@ -131,10 +121,8 @@ impl SignatureBuiltinRunner {
                     .get(&pubkey_addr)
                     .ok_or_else(|| MemoryError::SignatureNotFound(Box::new(pubkey_addr)))?;
 
-                let public_key = Felt252::from_bytes_be(&pubkey.to_bytes_be());
                 let (r, s) = (signature.r, signature.s);
-                let message = Felt252::from_bytes_be(&msg.to_bytes_be());
-                match verify(&public_key, &message, &r, &s) {
+                match verify(&pubkey, &msg, &r, &s) {
                     Ok(true) => Ok(vec![]),
                     _ => Err(MemoryError::InvalidSignature(Box::new((
                         format!("({}, {})", signature.r, signature.s),
@@ -171,15 +159,7 @@ impl SignatureBuiltinRunner {
             .signatures
             .borrow()
             .iter()
-            .map(|(k, v)| {
-                (
-                    *k,
-                    (
-                        Felt252::from_bytes_be(&v.r.to_bytes_be()),
-                        Felt252::from_bytes_be(&v.s.to_bytes_be()),
-                    ),
-                )
-            })
+            .map(|(k, v)| (*k, (v.r, v.s)))
             .collect();
         BuiltinAdditionalData::Signature(signatures)
     }
@@ -197,13 +177,9 @@ impl SignatureBuiltinRunner {
             if addr.segment_index != self.base as isize {
                 return Err(RunnerError::InvalidAdditionalData(BuiltinName::ecdsa));
             }
-            self.signatures.borrow_mut().insert(
-                *addr,
-                Signature {
-                    r: Felt252::from_bytes_be(&r.to_bytes_be()),
-                    s: Felt252::from_bytes_be(&s.to_bytes_be()),
-                },
-            );
+            self.signatures
+                .borrow_mut()
+                .insert(*addr, Signature { r: *r, s: *s });
         }
         Ok(())
     }
@@ -235,7 +211,7 @@ impl SignatureBuiltinRunner {
                     pubkey: *pubkey,
                     msg: *msg,
                     signature_input: SignatureInput {
-                        r: Felt252::from_bytes_be(&signature.r.to_bytes_be()),
+                        r: signature.r,
                         w: Felt252::from(
                             &div_mod(
                                 &BigInt::one(),

From 6fbb83e9da1d302ce1bfbabbed024c5c726b96ca Mon Sep 17 00:00:00 2001
From: VolodymyrBg <aqdrgg19@gmail.com>
Date: Mon, 9 Feb 2026 10:15:36 +0200
Subject: [PATCH 2/2] Update CHANGELOG.md

---
 CHANGELOG.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9c2b25e9a3..9a7242ee79 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,8 @@ Both branches support Stwo prover opcodes (Blake2s, QM31) since v2.0.0.
 
 #### Upcoming Changes
 
+* perf: remove redundant Felt252 bytes roundtrip in SignatureBuiltinRunner [#2323](https://github.com/lambdaclass/cairo-vm/pull/2323)
+
 * feat: Make `write_encoded` API public again [#2306](https://github.com/lambdaclass/cairo-vm/pull/2306)
 
 * refactor: deduplicate memcpy/memset scope initialization in builtin hint processor [#2313](https://github.com/lambdaclass/cairo-vm/pull/2313)