From ed315ffcae789358186fca2365ff51e6df1bad93 Mon Sep 17 00:00:00 2001
From: Isis Lovecruft <isis@torproject.org>
Date: Thu, 18 May 2017 23:00:55 +0000
Subject: [PATCH 1/3] Implement {AddAssign, SubAssign} for ExtendedPoint.

---
 src/curve.rs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/curve.rs b/src/curve.rs
index a9387a6..9d34f6f 100644
--- a/src/curve.rs
+++ b/src/curve.rs
@@ -83,6 +83,7 @@ use collections::Vec;
 use core::fmt::Debug;
 use core::iter::Iterator;
 use core::ops::{Add, Sub, Neg};
+use core::ops::{AddAssign, SubAssign};
 use core::ops::{Mul, MulAssign};
 use core::ops::Index;
 
@@ -802,6 +803,12 @@ impl<'a,'b> Add<&'b ExtendedPoint> for &'a ExtendedPoint {
     }
 }
 
+impl<'b> AddAssign<&'b ExtendedPoint> for ExtendedPoint {
+    fn add_assign(&mut self, _rhs: &'b ExtendedPoint) {
+        *self = (self as &ExtendedPoint) + _rhs;
+    }
+}
+
 impl<'a,'b> Sub<&'b ExtendedPoint> for &'a ExtendedPoint {
     type Output = ExtendedPoint;
     fn sub(self, other: &'b ExtendedPoint) -> ExtendedPoint {
@@ -809,6 +816,12 @@ impl<'a,'b> Sub<&'b ExtendedPoint> for &'a ExtendedPoint {
     }
 }
 
+impl<'b> SubAssign<&'b ExtendedPoint> for ExtendedPoint {
+    fn sub_assign(&mut self, _rhs: &'b ExtendedPoint) {
+        *self = (self as &ExtendedPoint) - _rhs;
+    }
+}
+
 impl<'a> Neg for &'a ExtendedPoint {
     type Output = ExtendedPoint;
 

From 27e4ea518165f3260abd303202cf6ec02b1e3f9c Mon Sep 17 00:00:00 2001
From: Isis Lovecruft <isis@torproject.org>
Date: Thu, 18 May 2017 23:01:31 +0000
Subject: [PATCH 2/3] Add a divider to separate Neg code from Add/Sub.

---
 src/curve.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/curve.rs b/src/curve.rs
index 9d34f6f..3656174 100644
--- a/src/curve.rs
+++ b/src/curve.rs
@@ -822,6 +822,10 @@ impl<'b> SubAssign<&'b ExtendedPoint> for ExtendedPoint {
     }
 }
 
+// ------------------------------------------------------------------------
+// Negation
+// ------------------------------------------------------------------------
+
 impl<'a> Neg for &'a ExtendedPoint {
     type Output = ExtendedPoint;
 

From e37445124931e1a0cb5af78af84adb9c21b8d843 Mon Sep 17 00:00:00 2001
From: Isis Lovecruft <isis@torproject.org>
Date: Thu, 18 May 2017 23:02:39 +0000
Subject: [PATCH 3/3] Implement {AddAssign, SubAssign} for DecafPoint.

---
 src/decaf.rs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/decaf.rs b/src/decaf.rs
index a97347f..4c4cd6c 100644
--- a/src/decaf.rs
+++ b/src/decaf.rs
@@ -36,6 +36,7 @@ use subtle::CTAssignable;
 use subtle::CTNegatable;
 
 use core::ops::{Add, Sub, Neg};
+use core::ops::{AddAssign, SubAssign};
 use core::ops::{Mul, MulAssign};
 
 use curve;
@@ -427,6 +428,12 @@ impl<'a, 'b> Add<&'b DecafPoint> for &'a DecafPoint {
     }
 }
 
+impl<'b> AddAssign<&'b DecafPoint> for DecafPoint {
+    fn add_assign(&mut self, _rhs: &DecafPoint) {
+        *self = (self as &DecafPoint) + _rhs;
+    }
+}
+
 impl<'a, 'b> Sub<&'b DecafPoint> for &'a DecafPoint {
     type Output = DecafPoint;
 
@@ -435,6 +442,12 @@ impl<'a, 'b> Sub<&'b DecafPoint> for &'a DecafPoint {
     }
 }
 
+impl<'b> SubAssign<&'b DecafPoint> for DecafPoint {
+    fn sub_assign(&mut self, _rhs: &DecafPoint) {
+        *self = (self as &DecafPoint) - _rhs;
+    }
+}
+
 impl<'a> Neg for &'a DecafPoint {
     type Output = DecafPoint;