Split Diffie-Hellman off almost completely, such that nearly none of

it builds if it is disabled.

Current deficiency: due to #if defined(BLAH) in the engine code,
Botan will not be binary compat across different configurations b/c
the vtable will change size.

Move some source from core/ to core/libstate where it belonged (engine stuff)

4 files changed, 66 insertions, 3 deletions

diff --git a/src/pubkey/dh/dh_core.h b/src/pubkey/dh/dh_core.h
index 3735f31e1..666e615fc 100644
--- a/src/pubkey/dh/dh_core.h
+++ b/src/pubkey/dh/dh_core.h
@@ -6,10 +6,8 @@
 #ifndef BOTAN_DH_CORE_H__
 #define BOTAN_DH_CORE_H__
 
-#include <botan/bigint.h>
+#include <botan/dh_op.h>
 #include <botan/blinding.h>
-#include <botan/pk_ops.h>
-#include <botan/dl_group.h>
 
 namespace Botan {
 
diff --git a/src/pubkey/dh/dh_op.cpp b/src/pubkey/dh/dh_op.cpp
new file mode 100644
index 000000000..3b87c6467
--- /dev/null
+++ b/src/pubkey/dh/dh_op.cpp
@@ -0,0 +1,20 @@
+/*************************************************
+* DH Operations Source File                      *
+* (C) 1999-2007 Jack Lloyd                       *
+*************************************************/
+
+#include <botan/dh_op.h>
+#include <botan/eng_def.h>
+
+namespace Botan {
+
+/*************************************************
+* Acquire a DH op                                *
+*************************************************/
+DH_Operation* Default_Engine::dh_op(const DL_Group& group,
+                                    const BigInt& x) const
+   {
+   return new Default_DH_Op(group, x);
+   }
+
+}
diff --git a/src/pubkey/dh/dh_op.h b/src/pubkey/dh/dh_op.h
new file mode 100644
index 000000000..4fbd3f5dc
--- /dev/null
+++ b/src/pubkey/dh/dh_op.h
@@ -0,0 +1,43 @@
+/*************************************************
+* DH Operations Header File                      *
+* (C) 1999-2008 Jack Lloyd                       *
+*************************************************/
+
+#ifndef BOTAN_DH_OPS_H__
+#define BOTAN_DH_OPS_H__
+
+#include <botan/dl_group.h>
+#include <botan/reducer.h>
+#include <botan/pow_mod.h>
+
+namespace Botan {
+
+/*************************************************
+* DH Operation Interface                         *
+*************************************************/
+class BOTAN_DLL DH_Operation
+   {
+   public:
+      virtual BigInt agree(const BigInt&) const = 0;
+      virtual DH_Operation* clone() const = 0;
+      virtual ~DH_Operation() {}
+   };
+
+/*************************************************
+* Botan's Default DH Operation                   *
+*************************************************/
+class Default_DH_Op : public DH_Operation
+   {
+   public:
+      BigInt agree(const BigInt& i) const { return powermod_x_p(i); }
+      DH_Operation* clone() const { return new Default_DH_Op(*this); }
+
+      Default_DH_Op(const DL_Group& group, const BigInt& x) :
+         powermod_x_p(x, group.get_p()) {}
+   private:
+      Fixed_Exponent_Power_Mod powermod_x_p;
+   };
+
+}
+
+#endif
diff --git a/src/pubkey/dh/info.txt b/src/pubkey/dh/info.txt
index 3765644c8..a54188c57 100644
--- a/src/pubkey/dh/info.txt
+++ b/src/pubkey/dh/info.txt
@@ -9,6 +9,8 @@ dh.cpp
 dh.h
 dh_core.cpp
 dh_core.h
+dh_op.h
+dh_op.cpp
 </add>
 
 <requires>