From 72a2111e03b0c8ecb1a1e25977b818aaefad06ba Mon Sep 17 00:00:00 2001
From: Kobi Gurkan <kobigurk@gmail.com>
Date: Mon, 27 Apr 2020 14:02:37 +0300
Subject: [PATCH] moves verify.rs to examples and adds comments about safety

---
 phase2/src/utils.rs                         | 4 ++--
 powersoftau/{src/bin => examples}/verify.rs | 4 ++++
 powersoftau/src/utils.rs                    | 2 +-
 3 files changed, 7 insertions(+), 3 deletions(-)
 rename powersoftau/{src/bin => examples}/verify.rs (98%)

diff --git a/phase2/src/utils.rs b/phase2/src/utils.rs
index 0cfc903..243f2b6 100644
--- a/phase2/src/utils.rs
+++ b/phase2/src/utils.rs
@@ -104,7 +104,7 @@ pub fn merge_pairs<G: CurveAffine>(v1: &[G], v2: &[G]) -> (G, G)
 
 
 /// Hashes to G2 using the first 32 bytes of `digest`. Panics if `digest` is less
-/// than 32 bytes.
+/// than 32 bytes. The input must be random.
 pub fn hash_to_g2(mut digest: &[u8]) -> G2
 {
     assert!(digest.len() >= 32);
@@ -179,4 +179,4 @@ pub fn pairing_to_vec(p: &Fq12) -> Vec<Vec<Vec<String>>> {
             ]
         ],
     ]
-}
\ No newline at end of file
+}
diff --git a/powersoftau/src/bin/verify.rs b/powersoftau/examples/verify.rs
similarity index 98%
rename from powersoftau/src/bin/verify.rs
rename to powersoftau/examples/verify.rs
index 0478f19..64943e2 100644
--- a/powersoftau/src/bin/verify.rs
+++ b/powersoftau/examples/verify.rs
@@ -1,3 +1,7 @@
+//! verify.rs has multiple problems and shouldn't be used in production without further changes.
+//! Specifically, it doesn't verify the hash chain from each of the contributions and it has a
+//! hardcoded number of participants.
+
 use bellman_ce::pairing::bn256::Bn256;
 use bellman_ce::pairing::bn256::{G1, G2};
 use bellman_ce::pairing::{CurveAffine, CurveProjective};
diff --git a/powersoftau/src/utils.rs b/powersoftau/src/utils.rs
index 5edcc2f..8f032c6 100644
--- a/powersoftau/src/utils.rs
+++ b/powersoftau/src/utils.rs
@@ -27,7 +27,7 @@ pub fn calculate_hash(input_map: &Mmap) -> GenericArray<u8, U64> {
 }
 
 /// Hashes to G2 using the first 32 bytes of `digest`. Panics if `digest` is less
-/// than 32 bytes.
+/// than 32 bytes. The input must be random.
 pub fn hash_to_g2<E: Engine>(mut digest: &[u8]) -> E::G2 {
     assert!(digest.len() >= 32);