From dede91a5b7d815f601e74cbd87f889ef1c8394f1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fran=C3=A7ois=20Garillot?= <francois@garillot.net>
Date: Thu, 3 Sep 2020 10:46:09 -0400
Subject: [PATCH] Add additional test vectors from Signal

---
 src/elligator/mod.rs | 64 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 62 insertions(+), 2 deletions(-)

diff --git a/src/elligator/mod.rs b/src/elligator/mod.rs
index 76dc438..2df11f7 100644
--- a/src/elligator/mod.rs
+++ b/src/elligator/mod.rs
@@ -6,7 +6,7 @@
 
 mod field;
 
-use curve25519_dalek::{edwards::EdwardsPoint, montgomery::MontgomeryPoint, scalar::Scalar};
+use curve25519_dalek::{edwards::EdwardsPoint, montgomery::MontgomeryPoint};
 use field::FieldElement51;
 use sha2::Digest;
 use subtle::{ConditionallyNegatable, ConditionallySelectable};
@@ -36,7 +36,7 @@ fn elligator_signal(r_0: &FieldElement51) -> MontgomeryPoint {
     MontgomeryPoint(u.to_bytes())
 }
 
-fn hash_to_point(bytes: &[u8]) -> EdwardsPoint {
+pub fn hash_to_point(bytes: &[u8]) -> EdwardsPoint {
     let mut hash = sha2::Sha512::new();
     hash.update(bytes);
     let h = hash.finalize();
@@ -113,4 +113,64 @@ mod tests {
         let hashed = hash_to_point(&bits);
         assert_eq!(hashed.compress().to_bytes(), HASHTOPOINT_CORRECT_OUTPUT2);
     }
+
+    /////////////////////////////////////////
+    // Additional test vectors from Signal //
+    /////////////////////////////////////////
+
+    fn test_vectors() -> Vec<Vec<&'static str>> {
+        vec![
+            vec![
+                "214f306e1576f5a7577636fe303ca2c625b533319f52442b22a9fa3b7ede809f",
+                "c95becf0f93595174633b9d4d6bbbeb88e16fa257176f877ce426e1424626052",
+            ],
+            vec![
+                "2eb10d432702ea7f79207da95d206f82d5a3b374f5f89f17a199531f78d3bea6",
+                "d8f8b508edffbb8b6dab0f602f86a9dd759f800fe18f782fdcac47c234883e7f",
+            ],
+            vec![
+                "84cbe9accdd32b46f4a8ef51c85fd39d028711f77fb00e204a613fc235fd68b9",
+                "93c73e0289afd1d1fc9e4e78a505d5d1b2642fbdf91a1eff7d281930654b1453",
+            ],
+            vec![
+                "c85165952490dc1839cb69012a3d9f2cc4b02343613263ab93a26dc89fd58267",
+                "43cbe8685fd3c90665b91835debb89ff1477f906f5170f38a192f6a199556537",
+            ],
+            vec![
+                "26e7fc4a78d863b1a4ccb2ce0951fbcd021e106350730ee4157bacb4502e1b76",
+                "b6fc3d738c2c40719479b2f23818180cdafa72a14254d4016bbed8f0b788a835",
+            ],
+            vec![
+                "1618c08ef0233f94f0f163f9435ec7457cd7a8cd4bb6b160315d15818c30f7a2",
+                "da0b703593b29dbcd28ebd6e7baea17b6f61971f3641cae774f6a5137a12294c",
+            ],
+            vec![
+                "48b73039db6fcdcb6030c4a38e8be80b6390d8ae46890e77e623f87254ef149c",
+                "ca11b25acbc80566603eabeb9364ebd50e0306424c61049e1ce9385d9f349966",
+            ],
+            vec![
+                "a744d582b3a34d14d311b7629da06d003045ae77cebceeb4e0e72734d63bd07d",
+                "fad25a5ea15d4541258af8785acaf697a886c1b872c793790e60a6837b1adbc0",
+            ],
+            vec![
+                "80a6ff33494c471c5eff7efb9febfbcf30a946fe6535b3451cda79f2154a7095",
+                "57ac03913309b3f8cd3c3d4c49d878bb21f4d97dc74a1eaccbe5c601f7f06f47",
+            ],
+            vec![
+                "f06fc939bc10551a0fd415aebf107ef0b9c4ee1ef9a164157bdd089127782617",
+                "785b2a6a00a5579cc9da1ff997ce8339b6f9fb46c6f10cf7a12ff2986341a6e0",
+            ],
+        ]
+    }
+
+    #[test]
+    fn additional_signal_test_vectors() {
+        for vector in test_vectors().iter() {
+            let input = hex::decode(vector[0]).unwrap();
+            let output = hex::decode(vector[1]).unwrap();
+
+            let point = hash_to_point(&input);
+            assert_eq!(point.compress().to_bytes(), output[..]);
+        }
+    }
 }