From 7f267b20ca60727eeca7c4531f297eb82fbc10ee Mon Sep 17 00:00:00 2001
From: Jack Lloyd <jack@randombit.net>
Date: Thu, 8 Dec 2016 20:53:31 -0500
Subject: Inline Twofish::rs_mul into its only caller

---
 src/lib/block/twofish/twofish.cpp | 41 ++++++++++++++++++---------------------
 src/lib/block/twofish/twofish.h   |  2 --
 2 files changed, 19 insertions(+), 24 deletions(-)

(limited to 'src/lib/block/twofish')

diff --git a/src/lib/block/twofish/twofish.cpp b/src/lib/block/twofish/twofish.cpp
index a98ae8e70..0b30d4080 100644
--- a/src/lib/block/twofish/twofish.cpp
+++ b/src/lib/block/twofish/twofish.cpp
@@ -127,7 +127,25 @@ void Twofish::key_schedule(const byte key[], size_t length)
    secure_vector<byte> S(16);
 
    for(size_t i = 0; i != length; ++i)
-      rs_mul(&S[4*(i/8)], key[i], i);
+      {
+      /*
+      * Do one column of the RS matrix multiplcation
+      */
+      if(key[i])
+         {
+         byte X = POLY_TO_EXP[key[i] - 1];
+
+         byte RS1 = RS[(4*i  ) % 32];
+         byte RS2 = RS[(4*i+1) % 32];
+         byte RS3 = RS[(4*i+2) % 32];
+         byte RS4 = RS[(4*i+3) % 32];
+
+         S[4*(i/8)  ] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS1 - 1]) % 255];
+         S[4*(i/8)+1] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS2 - 1]) % 255];
+         S[4*(i/8)+2] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS3 - 1]) % 255];
+         S[4*(i/8)+3] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS4 - 1]) % 255];
+         }
+      }
 
    if(length == 16)
       {
@@ -212,27 +230,6 @@ void Twofish::key_schedule(const byte key[], size_t length)
       }
    }
 
-/*
-* Do one column of the RS matrix multiplcation
-*/
-void Twofish::rs_mul(byte S[4], byte key, size_t offset)
-   {
-   if(key)
-      {
-      byte X = POLY_TO_EXP[key - 1];
-
-      byte RS1 = RS[(4*offset  ) % 32];
-      byte RS2 = RS[(4*offset+1) % 32];
-      byte RS3 = RS[(4*offset+2) % 32];
-      byte RS4 = RS[(4*offset+3) % 32];
-
-      S[0] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS1 - 1]) % 255];
-      S[1] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS2 - 1]) % 255];
-      S[2] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS3 - 1]) % 255];
-      S[3] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS4 - 1]) % 255];
-      }
-   }
-
 /*
 * Clear memory of sensitive data
 */
diff --git a/src/lib/block/twofish/twofish.h b/src/lib/block/twofish/twofish.h
index 42991e354..b8021263e 100644
--- a/src/lib/block/twofish/twofish.h
+++ b/src/lib/block/twofish/twofish.h
@@ -27,8 +27,6 @@ class BOTAN_DLL Twofish final : public Block_Cipher_Fixed_Params<16, 16, 32, 8>
    private:
       void key_schedule(const byte[], size_t) override;
 
-      static void rs_mul(byte[4], byte, size_t);
-
       static const u32bit MDS0[256];
       static const u32bit MDS1[256];
       static const u32bit MDS2[256];
-- 
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