Fold an XOR operation that was happening during SEED encryption/decryption to

occur inside the key schedule instead. This should lead to (slightly) better
scheduling in the compiled code by reducing the length of a critical path.

1 files changed, 6 insertions, 6 deletions

diff --git a/src/seed.cpp b/src/seed.cpp
index 9ed05b28f..765466ab6 100644
--- a/src/seed.cpp
+++ b/src/seed.cpp
@@ -34,14 +34,14 @@ void SEED::enc(const byte in[], byte out[]) const
       u32bit T0, T1;
 
       T0 = B2 ^ K[2*j];
-      T1 = G(T0 ^ B3 ^ K[2*j+1]);
+      T1 = G(B2 ^ B3 ^ K[2*j+1]);
       T0 = G(T1 + T0);
       T1 = G(T1 + T0);
       B1 ^= T1;
       B0 ^= T0 + T1;
 
       T0 = B0 ^ K[2*j+2];
-      T1 = G(T0 ^ B1 ^ K[2*j+3]);
+      T1 = G(B0 ^ B1 ^ K[2*j+3]);
       T0 = G(T1 + T0);
       T1 = G(T1 + T0);
       B3 ^= T1;
@@ -68,14 +68,14 @@ void SEED::dec(const byte in[], byte out[]) const
       u32bit T0, T1;
 
       T0 = B2 ^ K[30-2*j];
-      T1 = G(T0 ^ B3 ^ K[31-2*j]);
+      T1 = G(B2 ^ B3 ^ K[31-2*j]);
       T0 = G(T1 + T0);
       T1 = G(T1 + T0);
       B1 ^= T1;
       B0 ^= T0 + T1;
 
       T0 = B0 ^ K[28-2*j];
-      T1 = G(T0 ^ B1 ^ K[29-2*j]);
+      T1 = G(B0 ^ B1 ^ K[29-2*j]);
       T0 = G(T1 + T0);
       T1 = G(T1 + T0);
       B3 ^= T1;
@@ -107,14 +107,14 @@ void SEED::key(const byte key[], u32bit)
    for(u32bit j = 0; j != 16; j += 2)
       {
       K[2*j  ] = G(WK[0] + WK[2] - RC[j]);
-      K[2*j+1] = G(WK[1] - WK[3] + RC[j]);
+      K[2*j+1] = G(WK[1] - WK[3] + RC[j]) ^ K[2*j];
 
       byte T = get_byte(3, WK[0]);
       WK[0] = (WK[0] >> 8) | (get_byte(3, WK[1]) << 24);
       WK[1] = (WK[1] >> 8) | (T << 24);
 
       K[2*j+2] = G(WK[0] + WK[2] - RC[j+1]);
-      K[2*j+3] = G(WK[1] - WK[3] + RC[j+1]);
+      K[2*j+3] = G(WK[1] - WK[3] + RC[j+1]) ^ K[2*j+2];
 
       T = get_byte(0, WK[3]);
       WK[3] = (WK[3] << 8) | get_byte(0, WK[2]);