From e9a7bfc3a6ef368dcc7eba482356c166f7d888d7 Mon Sep 17 00:00:00 2001
From: Arseniy Ankudinov <afalinuz@gmail.com>
Date: Wed, 23 Sep 2020 18:54:58 +0300
Subject: [PATCH] disable gost key mask on gost94 digest steps due to
 performance issues

---
 gost89.c | 20 ++++++++++++++++----
 gost89.h |  2 ++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/gost89.c b/gost89.c
index 953c6ec..337204b 100644
--- a/gost89.c
+++ b/gost89.c
@@ -444,15 +444,13 @@ void gost_dec_cfb(gost_ctx * ctx, const byte * iv, const byte * cipher,
 void gost_enc_with_key(gost_ctx * c, byte * key, byte * inblock,
                        byte * outblock)
 {
-    gost_key(c, key);
+    gost_key_nomask(c, key);
     gostcrypt(c, inblock, outblock);
 }
 
-/* Set 256 bit gost89 key into context */
-void gost_key(gost_ctx * c, const byte * k)
+static void gost_key_impl(gost_ctx * c, const byte * k)
 {
     int i, j;
-    RAND_priv_bytes((unsigned char *)c->mask, sizeof(c->mask));
     for (i = 0, j = 0; i < 8; ++i, j += 4) {
         c->key[i] =
             (k[j] | (k[j + 1] << 8) | (k[j + 2] << 16) | ((word32) k[j + 3] <<
@@ -460,6 +458,20 @@ void gost_key(gost_ctx * c, const byte * k)
     }
 }
 
+/* Set 256 bit gost89 key into context */
+void gost_key(gost_ctx * c, const byte * k)
+{
+    RAND_priv_bytes((unsigned char *)c->mask, sizeof(c->mask));
+    gost_key_impl(c, k);
+}
+
+/* Set 256 bit gost89 key into context without key mask */
+void gost_key_nomask(gost_ctx * c, const byte * k)
+{
+    memset(c->mask, 0, sizeof(c->mask));
+    gost_key_impl(c, k);
+}
+
 /* Set 256 bit Magma key into context */
 void magma_key(gost_ctx * c, const byte * k)
 {
diff --git a/gost89.h b/gost89.h
index 569db5b..b67375b 100644
--- a/gost89.h
+++ b/gost89.h
@@ -60,6 +60,8 @@ void gostcrypt(gost_ctx * c, const byte * in, byte * out);
 void gostdecrypt(gost_ctx * c, const byte * in, byte * out);
 /* Set key into context */
 void gost_key(gost_ctx * c, const byte * k);
+/* Set key into context without key mask */
+void gost_key_nomask(gost_ctx * c, const byte * k);
 /* Set key into context */
 void magma_key(gost_ctx * c, const byte * k);
 /* Get key from context */
-- 
2.39.5