From ea5efcdc29eda2bf43b13841e1bfe0ad1e132b60 Mon Sep 17 00:00:00 2001
From: Henry & Isis <henry+isis@en.ciph.re>
Date: Mon, 20 Feb 2017 03:45:49 -0800
Subject: [PATCH] Add impl of Identity for DecafPoint and CompressedDecaf

---
 src/decaf.rs | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/decaf.rs b/src/decaf.rs
index 61d926c..06cf656 100644
--- a/src/decaf.rs
+++ b/src/decaf.rs
@@ -30,6 +30,7 @@ use core::ops::{Add, Sub, Neg};
 use curve::ExtendedPoint;
 use curve::BasepointMult;
 use curve::ScalarMult;
+use curve::Identity;
 use scalar::Scalar;
 
 // ------------------------------------------------------------------------
@@ -79,6 +80,12 @@ impl CompressedDecaf {
     }
 }
 
+impl Identity for CompressedDecaf {
+    fn identity() -> CompressedDecaf {
+        CompressedDecaf([0u8;32])
+    }
+}
+
 /// A point in a prime-order group.
 ///
 /// XXX think about how this API should work
@@ -165,6 +172,12 @@ impl DecafPoint {
     }
 }
 
+impl Identity for DecafPoint {
+    fn identity() -> DecafPoint {
+        DecafPoint(ExtendedPoint::identity())
+    }
+}
+
 // ------------------------------------------------------------------------
 // Equality
 // ------------------------------------------------------------------------
@@ -262,7 +275,7 @@ mod test {
 
     #[test]
     fn test_decaf_decompress_id() {
-        let compressed_id = CompressedDecaf([0u8; 32]);
+        let compressed_id = CompressedDecaf::identity();
         let id = compressed_id.decompress().unwrap();
         // This should compress (as ed25519) to the following:
         let mut bytes = [0u8; 32]; bytes[0] = 1;
@@ -271,8 +284,8 @@ mod test {
 
     #[test]
     fn test_decaf_compress_id() {
-        let id = DecafPoint(ExtendedPoint::identity());
-        assert_eq!(id.compress(), CompressedDecaf([0u8; 32]));
+        let id = DecafPoint::identity();
+        assert_eq!(id.compress(), CompressedDecaf::identity());
     }
 
     #[test]