From 15633ad434fe58f4b2a59d90e5ee0abacd1e3e11 Mon Sep 17 00:00:00 2001
From: Kobi Gurkan <kobigurk@gmail.com>
Date: Fri, 17 Aug 2018 18:34:54 +0300
Subject: [PATCH] pedersen hashes: example of size limit bug

---
 bellman/src/gadgets/lookup.rs             |  1 +
 zcash_primitives/src/pedersen_hash.rs     | 19 ++++++++++++++++---
 zcash_proofs/src/circuit/pedersen_hash.rs |  8 ++++++--
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/bellman/src/gadgets/lookup.rs b/bellman/src/gadgets/lookup.rs
index bbb1da6..0c55801 100644
--- a/bellman/src/gadgets/lookup.rs
+++ b/bellman/src/gadgets/lookup.rs
@@ -154,6 +154,7 @@ where
         Ok(tmp)
     })?;
 
+
     let one = CS::one();
 
     // Compute the coefficients for the lookup constraints
diff --git a/zcash_primitives/src/pedersen_hash.rs b/zcash_primitives/src/pedersen_hash.rs
index f49fcb7..11dc387 100644
--- a/zcash_primitives/src/pedersen_hash.rs
+++ b/zcash_primitives/src/pedersen_hash.rs
@@ -18,7 +18,7 @@ impl Personalization {
                 (0..6).map(|i| (num >> i) & 1 == 1).collect()
             }
             Personalization::Empty => {
-                vec![true, true, true, false, false, false]
+                vec![true, true, true, true, true, true]
             }
         }
     }
@@ -115,13 +115,26 @@ where
 
 #[cfg(test)]
 mod test {
-    use crate::jubjub::*;
+    use crate::{
+        jubjub::*,
+        pedersen_hash::{pedersen_hash, Personalization},
+    };
+    use pairing::bls12_381::{Bls12, Fr};
 
     #[test]
-    fn test_pedersen_hash_generators() {
+    fn test_pedersen_hash_noncircuit() {
         let params = &JubjubBls12::new();
+        /*
         for (i, generator) in params.pedersen_hash_generators().iter().enumerate() {
             println!("generator {}, x={}, y={}", i, generator.to_xy().0, generator.to_xy().1)
         }
+        */
+
+        let mut input: Vec<bool> = vec![];
+        for i in 0..(63*3*4+1) {
+            input.push(true);
+        }
+        let p = pedersen_hash::<Bls12, _>(Personalization::Empty, input, &params).to_xy();
+        println!("hash = {}, {}", p.0, p.1);
     }
 }
diff --git a/zcash_proofs/src/circuit/pedersen_hash.rs b/zcash_proofs/src/circuit/pedersen_hash.rs
index 82703fa..7f43b1c 100644
--- a/zcash_proofs/src/circuit/pedersen_hash.rs
+++ b/zcash_proofs/src/circuit/pedersen_hash.rs
@@ -41,6 +41,7 @@ where
             let b = bits.next().unwrap_or(&boolean_false);
             let c = bits.next().unwrap_or(&boolean_false);
 
+
             let tmp = lookup3_xy_with_conditional_negation(
                 cs.namespace(|| format!("segment {}, window {}", segment_i, window_i)),
                 &[a.clone(), b.clone(), c.clone()],
@@ -213,16 +214,19 @@ mod test {
     fn test_pedersen_hash_alternative() {
         let params = &JubjubBls12::new();
 
-        let mut input: Vec<bool> = vec![true, true, true, false, false, false, true, true, true, false, false, false, true, true, true, false, false, false, true, true, true, false, false, false, true, true, true, false, false, false, true, true, true, false, false, false, true, true, true, false, true, false, true, true, true, true, true, false, true, false, false, false, true, true, false, false, false, false, false, false, false, false, false, false, true, false, false, false, true, false, true, true, true, false, false, true, true, false, true, true, true, true, true, false, true, true, false, true, true, false, true, false, true, false, true, true, false, true, false, true, true, false, false, false, false, false, true, true, false, true, false, true, true, true, true, false, true, false, true, false, false, false, false, true, true, true, false, true, true, true, false, true, false, false, true, false, true, true, true, false, false, false, true, true];
+        let mut input: Vec<bool> = vec![];
+        for i in 0..(63*3*4+1) {
+            input.push(true);
+        }
 
         let mut cs = TestConstraintSystem::<Bls12>::new();
 
+
         let input_bools: Vec<Boolean> = input.iter().enumerate().map(|(i, b)| {
             Boolean::from(
                 AllocatedBit::alloc(cs.namespace(|| format!("input {}", i)), Some(*b)).unwrap()
             )
         }).collect();
-
         let res = pedersen_hash(
             cs.namespace(|| "pedersen hash"),
             Personalization::Empty,