Change the BlockCipher interface to support multi-block encryption and

decryption. Currently only used for counter mode. Doesn't offer much
advantage as-is (though might help slightly, in terms of cache effects),
but allows for SIMD implementations to process multiple blocks in parallel
when possible. Particularly thinking here of Serpent; TEA/XTEA also seem
promising in this sense, as is Threefish once that is implemented as a
standalone block cipher.

2 files changed, 34 insertions, 22 deletions

diff --git a/src/block/tea/tea.cpp b/src/block/tea/tea.cpp
index 2b4212d9c..de30858da 100644
--- a/src/block/tea/tea.cpp
+++ b/src/block/tea/tea.cpp
@@ -13,37 +13,49 @@ namespace Botan {
 /*
 * TEA Encryption
 */
-void TEA::enc(const byte in[], byte out[]) const
+void TEA::encrypt_n(const byte in[], byte out[], u32bit blocks) const
    {
-   u32bit L = load_be<u32bit>(in, 0), R = load_be<u32bit>(in, 1);
-
-   u32bit S = 0;
-   for(u32bit j = 0; j != 32; ++j)
+   for(u32bit i = 0; i != blocks; ++i)
       {
-      S += 0x9E3779B9;
-      L += ((R << 4) + K[0]) ^ (R + S) ^ ((R >> 5) + K[1]);
-      R += ((L << 4) + K[2]) ^ (L + S) ^ ((L >> 5) + K[3]);
-      }
+      u32bit L = load_be<u32bit>(in, 0), R = load_be<u32bit>(in, 1);
+
+      u32bit S = 0;
+      for(u32bit j = 0; j != 32; ++j)
+         {
+         S += 0x9E3779B9;
+         L += ((R << 4) + K[0]) ^ (R + S) ^ ((R >> 5) + K[1]);
+         R += ((L << 4) + K[2]) ^ (L + S) ^ ((L >> 5) + K[3]);
+         }
 
-   store_be(out, L, R);
+      store_be(out, L, R);
+
+      in += BLOCK_SIZE;
+      out += BLOCK_SIZE;
+      }
    }
 
 /*
 * TEA Decryption
 */
-void TEA::dec(const byte in[], byte out[]) const
+void TEA::decrypt_n(const byte in[], byte out[], u32bit blocks) const
    {
-   u32bit L = load_be<u32bit>(in, 0), R = load_be<u32bit>(in, 1);
-
-   u32bit S = 0xC6EF3720;
-   for(u32bit j = 0; j != 32; ++j)
+   for(u32bit i = 0; i != blocks; ++i)
       {
-      R -= ((L << 4) + K[2]) ^ (L + S) ^ ((L >> 5) + K[3]);
-      L -= ((R << 4) + K[0]) ^ (R + S) ^ ((R >> 5) + K[1]);
-      S -= 0x9E3779B9;
-      }
+      u32bit L = load_be<u32bit>(in, 0), R = load_be<u32bit>(in, 1);
+
+      u32bit S = 0xC6EF3720;
+      for(u32bit j = 0; j != 32; ++j)
+         {
+         R -= ((L << 4) + K[2]) ^ (L + S) ^ ((L >> 5) + K[3]);
+         L -= ((R << 4) + K[0]) ^ (R + S) ^ ((R >> 5) + K[1]);
+         S -= 0x9E3779B9;
+         }
 
-   store_be(out, L, R);
+      store_be(out, L, R);
+
+      in += BLOCK_SIZE;
+      out += BLOCK_SIZE;
+      }
    }
 
 /*
diff --git a/src/block/tea/tea.h b/src/block/tea/tea.h
index 8ddf3e330..141899e88 100644
--- a/src/block/tea/tea.h
+++ b/src/block/tea/tea.h
@@ -23,8 +23,8 @@ class BOTAN_DLL TEA : public BlockCipher
       BlockCipher* clone() const { return new TEA; }
       TEA() : BlockCipher(8, 16) {}
    private:
-      void enc(const byte[], byte[]) const;
-      void dec(const byte[], byte[]) const;
+      void encrypt_n(const byte in[], byte out[], u32bit blocks) const;
+      void decrypt_n(const byte in[], byte out[], u32bit blocks) const;
       void key_schedule(const byte[], u32bit);
       SecureBuffer<u32bit, 4> K;
    };