From d2ab89bdc540c6127e027bc3abaf3c2fccd279b1 Mon Sep 17 00:00:00 2001
From: Michael Hamburg <mike@shiftleft.org>
Date: Wed, 28 Jan 2015 16:53:42 -0800
Subject: [PATCH] better docs on Elligator

---
 include/decaf.h | 15 ++++++++++++++-
 src/decaf.c     | 11 +++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/include/decaf.h b/include/decaf.h
index 010cfb8..a8ffe7d 100644
--- a/include/decaf.h
+++ b/include/decaf.h
@@ -192,12 +192,25 @@ decaf_bool_t decaf_valid (
  * is indifferentiable from a random oracle.
  *
  * @param [in] hashed_data Output of some hash function.
- * @param [out] pt The hashed input
+ * @param [out] pt The data hashed to the curve.
  */
 void decaf_nonuniform_map_to_curve (
     decaf_point_t pt,
     const unsigned char hashed_data[DECAF_SER_BYTES]
 ) API_VIS NONNULL2;
+
+/**
+ * @brief Indifferentiable hash function encoding to curve.
+ *
+ * Equivalent to calling decaf_nonuniform_map_to_curve twice and adding.
+ *
+ * @param [in] hashed_data Output of some hash function.
+ * @param [out] pt The data hashed to the curve.
+ */ 
+void decaf_uniform_map_to_curve (
+    decaf_point_t pt,
+    const unsigned char hashed_data[2*DECAF_SER_BYTES]
+) API_VIS NONNULL2;
     
 #undef API_VIS
 #undef WARN_UNUSED
diff --git a/src/decaf.c b/src/decaf.c
index d699eee..fbb92fc 100644
--- a/src/decaf.c
+++ b/src/decaf.c
@@ -414,6 +414,17 @@ void decaf_nonuniform_map_to_curve (
     gf_mul(p->t,b,e);
 }
 
+
+void decaf_uniform_map_to_curve (
+    decaf_point_t pt,
+    const unsigned char hashed_data[2*DECAF_SER_BYTES]
+) {
+    decaf_point_t pt2;
+    decaf_nonuniform_map_to_curve(pt,hashed_data);
+    decaf_nonuniform_map_to_curve(pt2,&hashed_data[DECAF_SER_BYTES]);
+    decaf_add(pt,pt,pt2);
+}
+
 decaf_bool_t decaf_valid (
     const decaf_point_t p
 ) {