From 5773d9e998e626328bf49a655d49df4810e6f980 Mon Sep 17 00:00:00 2001
From: Vsevolod Stakhov <vsevolod@highsecure.ru>
Date: Fri, 6 Feb 2015 17:15:08 +0000
Subject: [PATCH] Set curve25519 bits on keypair generation.

---
 src/libcryptobox/curve25519/curve25519-donna-c64.c | 9 +--------
 src/libcryptobox/curve25519/curve25519-donna.c     | 9 +--------
 src/libcryptobox/curve25519/ref.c                  | 9 ++-------
 3 files changed, 4 insertions(+), 23 deletions(-)

diff --git a/src/libcryptobox/curve25519/curve25519-donna-c64.c b/src/libcryptobox/curve25519/curve25519-donna-c64.c
index 2d693ee44..e6a5045ad 100644
--- a/src/libcryptobox/curve25519/curve25519-donna-c64.c
+++ b/src/libcryptobox/curve25519/curve25519-donna-c64.c
@@ -482,17 +482,10 @@ int curve25519 (u8 *, const u8 *, const u8 *);
 int curve25519 (u8 *mypublic, const u8 *secret, const u8 *basepoint)
 {
 	limb bp[5], x[5], z[5], zmone[5];
-	uint8_t e[32];
 	int i;
 
-	for (i = 0; i < 32; ++i)
-		e[i] = secret[i];
-	e[0] &= 248;
-	e[31] &= 127;
-	e[31] |= 64;
-
 	fexpand (bp, basepoint);
-	cmult (x, z, e, bp);
+	cmult (x, z, secret, bp);
 	crecip (zmone, z);
 	fmul (z, x, zmone);
 	fcontract (mypublic, z);
diff --git a/src/libcryptobox/curve25519/curve25519-donna.c b/src/libcryptobox/curve25519/curve25519-donna.c
index f9f19a632..e6a50b87f 100644
--- a/src/libcryptobox/curve25519/curve25519-donna.c
+++ b/src/libcryptobox/curve25519/curve25519-donna.c
@@ -894,17 +894,10 @@ static void crecip (limb *out, const limb *z)
 int curve25519 (u8 *mypublic, const u8 *secret, const u8 *basepoint)
 {
 	limb bp[10], x[10], z[11], zmone[10];
-	uint8_t e[32];
 	int i;
 
-	for (i = 0; i < 32; ++i)
-		e[i] = secret[i];
-	e[0] &= 248;
-	e[31] &= 127;
-	e[31] |= 64;
-
 	fexpand (bp, basepoint);
-	cmult (x, z, e, bp);
+	cmult (x, z, secret, bp);
 	crecip (zmone, z);
 	fmul (z, x, zmone);
 	fcontract (mypublic, z);
diff --git a/src/libcryptobox/curve25519/ref.c b/src/libcryptobox/curve25519/ref.c
index ac3827c27..7e4820906 100644
--- a/src/libcryptobox/curve25519/ref.c
+++ b/src/libcryptobox/curve25519/ref.c
@@ -303,17 +303,12 @@ int curve25519 (unsigned char *q, const unsigned char *n,
 		const unsigned char *p)
 {
 	unsigned int work[96];
-	unsigned char e[32];
 	unsigned int i;
-	for (i = 0; i < 32; ++i)
-		e[i] = n[i];
-	e[0] &= 248;
-	e[31] &= 127;
-	e[31] |= 64;
+
 	for (i = 0; i < 32; ++i)
 		work[i] = p[i];
 	work[31] &= 127;
-	mainloop (work, e);
+	mainloop (work, n);
 	recip (work + 32, work + 32);
 	mult (work + 64, work, work + 32);
 	freeze (work + 64);
-- 
2.39.5