2 files changed, 36 insertions, 32 deletions

diff --git a/src/stream/turing/turing.cpp b/src/stream/turing/turing.cpp
index b988568c3..810f65ca4 100644
--- a/src/stream/turing/turing.cpp
+++ b/src/stream/turing/turing.cpp
@@ -218,25 +218,6 @@ u32bit Turing::fixedS(u32bit W)
    }
 
 /*
-* Generate the expanded Turing Sbox tables
-*/
-void Turing::gen_sbox(MemoryRegion<u32bit>& S, u32bit which,
-                      const MemoryRegion<u32bit>& K)
-   {
-   for(u32bit j = 0; j != 256; ++j)
-      {
-      u32bit W = 0, C = j;
-
-      for(u32bit k = 0; k < K.size(); ++k)
-         {
-         C = SBOX[get_byte(which, K[k]) ^ C];
-         W ^= rotate_left(Q_BOX[C], k + 8*which);
-         }
-      S[j] = (W & rotate_right(0x00FFFFFF, 8*which)) | (C << (24 - 8*which));
-      }
-   }
-
-/*
 * Turing Key Schedule
 */
 void Turing::key_schedule(const byte key[], u32bit length)
@@ -250,20 +231,41 @@ void Turing::key_schedule(const byte key[], u32bit length)
 
    PHT(K);
 
-   gen_sbox(S0, 0, K);
-   gen_sbox(S1, 1, K);
-   gen_sbox(S2, 2, K);
-   gen_sbox(S3, 3, K);
+   for(u32bit i = 0; i != 256; ++i)
+      {
+      u32bit W0 = 0, C0 = i;
+      u32bit W1 = 0, C1 = i;
+      u32bit W2 = 0, C2 = i;
+      u32bit W3 = 0, C3 = i;
+
+      for(u32bit j = 0; j < K.size(); ++j)
+         {
+         C0 = SBOX[get_byte(0, K[j]) ^ C0];
+         C1 = SBOX[get_byte(1, K[j]) ^ C1];
+         C2 = SBOX[get_byte(2, K[j]) ^ C2];
+         C3 = SBOX[get_byte(3, K[j]) ^ C3];
+
+         W0 ^= rotate_left(Q_BOX[C0], j);
+         W1 ^= rotate_left(Q_BOX[C1], j + 8);
+         W2 ^= rotate_left(Q_BOX[C2], j + 16);
+         W3 ^= rotate_left(Q_BOX[C3], j + 24);
+         }
+
+      S0[i] = (W0 & 0x00FFFFFF) | (C0 << 24);
+      S1[i] = (W1 & 0xFF00FFFF) | (C1 << 16);
+      S2[i] = (W2 & 0xFFFF00FF) | (C2 << 8);
+      S3[i] = (W3 & 0xFFFFFF00) | C3;
+      }
 
-   resync(0, 0);
+   set_iv(0, 0);
    }
 
 /*
 * Resynchronization
 */
-void Turing::resync(const byte iv[], u32bit length)
+void Turing::set_iv(const byte iv[], u32bit length)
    {
-   if(length % 4 != 0 || length > 16)
+   if(!valid_iv_length(length))
       throw Invalid_IV_Length(name(), length);
 
    SecureVector<u32bit> IV(length / 4);
@@ -293,7 +295,7 @@ void Turing::resync(const byte iv[], u32bit length)
 /*
 * Clear memory of sensitive data
 */
-void Turing::clear() throw()
+void Turing::clear()
    {
    S0.clear();
    S1.clear();
diff --git a/src/stream/turing/turing.h b/src/stream/turing/turing.h
index d48c1d8a8..7291647ea 100644
--- a/src/stream/turing/turing.h
+++ b/src/stream/turing/turing.h
@@ -18,19 +18,21 @@ namespace Botan {
 class BOTAN_DLL Turing : public StreamCipher
    {
    public:
-      void clear() throw();
+      void cipher(const byte in[], byte out[], u32bit length);
+      void set_iv(const byte[], u32bit);
+
+      bool valid_iv_length(u32bit iv_len) const
+         { return (iv_len % 4 == 0 && iv_len <= 16); }
+
+      void clear();
       std::string name() const { return "Turing"; }
       StreamCipher* clone() const { return new Turing; }
       Turing() : StreamCipher(4, 32, 4) { position = 0; }
    private:
-      void cipher(const byte[], byte[], u32bit);
       void key_schedule(const byte[], u32bit);
-      void resync(const byte[], u32bit);
       void generate();
 
       static u32bit fixedS(u32bit);
-      static void gen_sbox(MemoryRegion<u32bit>&, u32bit,
-                           const MemoryRegion<u32bit>&);
 
       static const u32bit Q_BOX[256];
       static const byte SBOX[256];