From 626c6b2b27138b00084edcfde811dde4d41a7753 Mon Sep 17 00:00:00 2001
From: Timofey Luin <timofey.luin@gmail.com>
Date: Fri, 10 May 2024 15:54:02 +0200
Subject: [PATCH] disallow unassigned witness

---
 halo2-ecc/src/ecc/hash_to_curve.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/halo2-ecc/src/ecc/hash_to_curve.rs b/halo2-ecc/src/ecc/hash_to_curve.rs
index 998c465e..d4fc3587 100644
--- a/halo2-ecc/src/ecc/hash_to_curve.rs
+++ b/halo2-ecc/src/ecc/hash_to_curve.rs
@@ -392,9 +392,8 @@ impl ExpandMessageChip for ExpandMsgXmd {
         let assigned_msg = msg
             .map(|cell| match cell {
                 QuantumCell::Existing(v) => v,
-                QuantumCell::Witness(v) => thread_pool.main().load_witness(v),
                 QuantumCell::Constant(v) => thread_pool.main().load_constant(v),
-                _ => unreachable!(),
+                _ => panic!("passing unassigned witness to this function is insecure"),
             })
             .collect_vec();