From 3e95bfad2765b90abc48986af37372e7b389dee5 Mon Sep 17 00:00:00 2001
From: samkim-crypto <skim13@cs.stanford.edu>
Date: Sun, 19 Nov 2023 10:37:00 +0900
Subject: [PATCH] forbid 0-bit range proof verification

---
 zk-token-sdk/src/range_proof/inner_product.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/zk-token-sdk/src/range_proof/inner_product.rs b/zk-token-sdk/src/range_proof/inner_product.rs
index 535d8d96335cc9..baecef78d7b076 100644
--- a/zk-token-sdk/src/range_proof/inner_product.rs
+++ b/zk-token-sdk/src/range_proof/inner_product.rs
@@ -205,7 +205,7 @@ impl InnerProductProof {
         transcript: &mut Transcript,
     ) -> Result<(Vec<Scalar>, Vec<Scalar>, Vec<Scalar>), RangeProofVerificationError> {
         let lg_n = self.L_vec.len();
-        if lg_n >= 32 {
+        if lg_n == 0 || lg_n >= 32 {
             // 4 billion multiplications should be enough for anyone
             // and this check prevents overflow in 1<<lg_n below.
             return Err(RangeProofVerificationError::InvalidBitSize);