Change the constructor for LubyRackoff. Previously it took a string,

however now instead it takes a HashFunction pointer, which it deletes
in its destructor.

Why the change? For one, lookup.h, while seemingly a bunch of standalone
functions, actually calls into a large mass of global state (in short, it
is icky). I have a plan in mind for removing much of this while still
providing a high level interface (actually hopefully better than now),
here is just the start.

Now, calling clone() on a LubyRackoff object will now return a new object
with a clone() of the HashFunction. Previously we called get_hash on
the name, which goes through the whole global lookup bit. This is also
good since if you construct one with (say) an OpenSSL provided hash,
clones of it will now also use that implementation.

2 files changed, 33 insertions, 27 deletions

diff --git a/src/def_alg.cpp b/src/def_alg.cpp
index 10c8e49d9..29e99d6a0 100644
--- a/src/def_alg.cpp
+++ b/src/def_alg.cpp
@@ -130,7 +130,6 @@ Default_Engine::find_block_cipher(const std::string& algo_spec) const
    HANDLE_TYPE_NO_ARGS("GOST", GOST);
    HANDLE_TYPE_NO_ARGS("IDEA", IDEA);
    HANDLE_TYPE_NO_ARGS("KASUMI", KASUMI);
-   HANDLE_TYPE_ONE_STRING("Luby-Rackoff", LubyRackoff);
    HANDLE_TYPE_NO_ARGS("MARS", MARS);
    HANDLE_TYPE_ONE_U32BIT("MISTY1", MISTY1, 8);
    HANDLE_TYPE_NO_ARGS("Noekeon", Noekeon);
@@ -146,6 +145,13 @@ Default_Engine::find_block_cipher(const std::string& algo_spec) const
    HANDLE_TYPE_NO_ARGS("Twofish", Twofish);
    HANDLE_TYPE_NO_ARGS("XTEA", XTEA);
 
+   if(algo_name == "Luby-Rackoff" && name.size() >= 2)
+      {
+      HashFunction* hash = find_hash(name[1]);
+      if(hash)
+         return new LubyRackoff(hash);
+      }
+
    if(algo_name == "Lion")
       {
       if(name.size() != 4)
diff --git a/src/lubyrack.cpp b/src/lubyrack.cpp
index 4a5408e1d..c9e6fc531 100644
--- a/src/lubyrack.cpp
+++ b/src/lubyrack.cpp
@@ -1,10 +1,9 @@
 /*************************************************
 * Luby-Rackoff Source File                       *
-* (C) 1999-2007 Jack Lloyd                       *
+* (C) 1999-2008 Jack Lloyd                       *
 *************************************************/
 
 #include <botan/lubyrack.h>
-#include <botan/lookup.h>
 #include <botan/xor_buf.h>
 
 namespace Botan {
@@ -14,28 +13,28 @@ namespace Botan {
 *************************************************/
 void LubyRackoff::enc(const byte in[], byte out[]) const
    {
-   const u32bit OUTPUT_LENGTH = hash->OUTPUT_LENGTH;
+   const u32bit len = hash->OUTPUT_LENGTH;
 
-   SecureVector<byte> buffer(OUTPUT_LENGTH);
+   SecureVector<byte> buffer(len);
    hash->update(K1);
-   hash->update(in, OUTPUT_LENGTH);
+   hash->update(in, len);
    hash->final(buffer);
-   xor_buf(out + OUTPUT_LENGTH, in + OUTPUT_LENGTH, buffer, OUTPUT_LENGTH);
+   xor_buf(out + len, in + len, buffer, len);
 
    hash->update(K2);
-   hash->update(out + OUTPUT_LENGTH, OUTPUT_LENGTH);
+   hash->update(out + len, len);
    hash->final(buffer);
-   xor_buf(out, in, buffer, OUTPUT_LENGTH);
+   xor_buf(out, in, buffer, len);
 
    hash->update(K1);
-   hash->update(out, OUTPUT_LENGTH);
+   hash->update(out, len);
    hash->final(buffer);
-   xor_buf(out + OUTPUT_LENGTH, buffer, OUTPUT_LENGTH);
+   xor_buf(out + len, buffer, len);
 
    hash->update(K2);
-   hash->update(out + OUTPUT_LENGTH, OUTPUT_LENGTH);
+   hash->update(out + len, len);
    hash->final(buffer);
-   xor_buf(out, buffer, OUTPUT_LENGTH);
+   xor_buf(out, buffer, len);
    }
 
 /*************************************************
@@ -43,28 +42,28 @@ void LubyRackoff::enc(const byte in[], byte out[]) const
 *************************************************/
 void LubyRackoff::dec(const byte in[], byte out[]) const
    {
-   const u32bit OUTPUT_LENGTH = hash->OUTPUT_LENGTH;
+   const u32bit len = hash->OUTPUT_LENGTH;
 
-   SecureVector<byte> buffer(OUTPUT_LENGTH);
+   SecureVector<byte> buffer(len);
    hash->update(K2);
-   hash->update(in + OUTPUT_LENGTH, OUTPUT_LENGTH);
+   hash->update(in + len, len);
    hash->final(buffer);
-   xor_buf(out, in, buffer, OUTPUT_LENGTH);
+   xor_buf(out, in, buffer, len);
 
    hash->update(K1);
-   hash->update(out, OUTPUT_LENGTH);
+   hash->update(out, len);
    hash->final(buffer);
-   xor_buf(out + OUTPUT_LENGTH, in + OUTPUT_LENGTH, buffer, OUTPUT_LENGTH);
+   xor_buf(out + len, in + len, buffer, len);
 
    hash->update(K2);
-   hash->update(out + OUTPUT_LENGTH, OUTPUT_LENGTH);
+   hash->update(out + len, len);
    hash->final(buffer);
-   xor_buf(out, buffer, OUTPUT_LENGTH);
+   xor_buf(out, buffer, len);
 
    hash->update(K1);
-   hash->update(out, OUTPUT_LENGTH);
+   hash->update(out, len);
    hash->final(buffer);
-   xor_buf(out + OUTPUT_LENGTH, buffer, OUTPUT_LENGTH);
+   xor_buf(out + len, buffer, len);
    }
 
 /*************************************************
@@ -91,7 +90,7 @@ void LubyRackoff::clear() throw()
 *************************************************/
 BlockCipher* LubyRackoff::clone() const
    {
-   return new LubyRackoff(hash->name());
+   return new LubyRackoff(hash->clone());
    }
 
 /*************************************************
@@ -105,9 +104,10 @@ std::string LubyRackoff::name() const
 /*************************************************
 * Luby-Rackoff Constructor                       *
 *************************************************/
-LubyRackoff::LubyRackoff(const std::string& hash_name) :
-   BlockCipher(2*output_length_of(hash_name), 2, 32, 2),
-   hash(get_hash(hash_name))
+LubyRackoff::LubyRackoff(HashFunction* h) :
+   BlockCipher(2 * (h ? h->OUTPUT_LENGTH: 0),
+               2, 32, 2),
+   hash(h)
    {
    }