From dd8b61da4a789300da9c39adbacadfcd4e3b958d Mon Sep 17 00:00:00 2001
From: Henry de Valence <hdevalence@hdevalence.ca>
Date: Tue, 15 Jan 2019 21:44:56 -0800
Subject: [PATCH 1/2] Add an X25519 basepoint constant

---
 src/x25519.rs | 33 +++++++++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/x25519.rs b/src/x25519.rs
index c265e6c..c5e342c 100644
--- a/src/x25519.rs
+++ b/src/x25519.rs
@@ -111,18 +111,43 @@ fn clamp_scalar(scalar: [u8; 32]) -> Scalar {
     Scalar::from_bits(s)
 }
 
-/// The x25519 function, as specified in RFC7748.
+/// The bare, byte-oriented x25519 function, exactly as specified in RFC7748.
+///
+/// This can be used with [`X25519_BASEPOINT_BYTES`] for people who
+/// cannot use the better, safer, and faster ephemeral DH API.
 pub fn x25519(k: [u8; 32], u: [u8; 32]) -> [u8; 32] {
     (clamp_scalar(k) * MontgomeryPoint(u)).to_bytes()
 }
 
+/// The X25519 basepoint, for use with the bare, byte-oriented x25519
+/// function.  This is provided for people who cannot use the typed
+/// ephemeral DH API for some reason.
+pub const X25519_BASEPOINT_BYTES: [u8; 32] = [
+    9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+];
+
 #[cfg(test)]
 mod test {
     use super::*;
 
-    fn do_rfc7748_ladder_test1(input_scalar: [u8; 32],
-                               input_point: [u8; 32],
-                               expected: [u8; 32]) {
+    #[test]
+    fn byte_basepoint_matches_edwards_scalar_mul() {
+        let mut scalar_bytes = [0x37; 32];
+
+        for i in 0..32 {
+            scalar_bytes[i] += 2;
+
+            let result = x25519(scalar_bytes, X25519_BASEPOINT_BYTES);
+
+            let expected = (&ED25519_BASEPOINT_TABLE * &clamp_scalar(scalar_bytes))
+                .to_montgomery()
+                .to_bytes();
+
+            assert_eq!(result, expected);
+        }
+    }
+
+    fn do_rfc7748_ladder_test1(input_scalar: [u8; 32], input_point: [u8; 32], expected: [u8; 32]) {
         let result = x25519(input_scalar, input_point);
 
         assert_eq!(result, expected);

From b21ab1324f2ce17e2ede679446da55de7303e290 Mon Sep 17 00:00:00 2001
From: Henry de Valence <hdevalence@hdevalence.ca>
Date: Tue, 15 Jan 2019 22:47:35 -0800
Subject: [PATCH 2/2] Bump minor version

---
 Cargo.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index 7c7cd3e..fe51ca2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "x25519-dalek"
-version = "0.4.1"
+version = "0.4.2"
 authors = ["Isis Lovecruft <isis@patternsinthevoid.net>", "DebugSteven <debugsteven@gmail.com>"]
 readme = "README.md"
 license = "BSD-3-Clause"