This checkin represents a pretty major change in how PK operations are

performed. Up until now, each key object (eg DSA_PublicKey or
ECDH_PrivateKey) had two jobs: contain the key material, and know how
to perform any operations on that key.  However because of a desire to
support alternative implementations (GNU MP, hardware, whatever),
there was a notion of operations, with the key objects containing an
op that they got via engine rather than actually implementing the
underlying algorithms directly.

Now, represent the operation as an abstract interface (typically
mapping a byte string to a byte string), and pass a plain Public_Key&
or Private_Key& to the engine. The engine does any checks it wants (eg
based on name, typeid, key sizes, etc), and either returns nothing
(I'll pass) or a pointer to a new operation that represents signatures
or encryption or what-have-you using that key.

This means that plain key objects no longer contain operations.  This
is a major break with the traditional interface. On the other hand,
using these 'bare' operations without padding, KDFs, etc is 99% of the
time a bad idea anyway (and if you really need them, there are options
so you get the bare op but via the pubkey.h interfaces).

Currently this change is only implemented for DH and ECDH (ie, key
agreement algorithms). Additionally the optional engines (gnump and
openssl) have not been updated. I'll probably wait to touch those
until after I can change them all in one go for all algos.

2 files changed, 23 insertions, 16 deletions

diff --git a/src/engine/def_engine/def_pk_ops.cpp b/src/engine/def_engine/def_pk_ops.cpp
index e1040142e..b2f53376d 100644
--- a/src/engine/def_engine/def_pk_ops.cpp
+++ b/src/engine/def_engine/def_pk_ops.cpp
@@ -24,11 +24,31 @@
 #endif
 
 #if defined(BOTAN_HAS_DIFFIE_HELLMAN)
-  #include <botan/dh_op.h>
+  #include <botan/dh.h>
+#endif
+
+#if defined(BOTAN_HAS_ECDH)
+  #include <botan/ecdh.h>
 #endif
 
 namespace Botan {
 
+PK_Ops::KA_Operation*
+Default_Engine::get_key_agreement_op(const Private_Key& key) const
+   {
+#if defined(BOTAN_HAS_DIFFIE_HELLMAN)
+   if(const DH_PrivateKey* dh = dynamic_cast<const DH_PrivateKey*>(&key))
+      return new DH_KA_Operation(*dh);
+#endif
+
+#if defined(BOTAN_HAS_ECDH)
+   if(const ECDH_PrivateKey* ecdh = dynamic_cast<const ECDH_PrivateKey*>(&key))
+      return new ECDH_KA_Operation(*ecdh);
+#endif
+
+   return 0;
+   }
+
 #if defined(BOTAN_HAS_IF_PUBLIC_KEY_FAMILY)
 /*
 * Acquire an IF op
@@ -75,15 +95,4 @@ ELG_Operation* Default_Engine::elg_op(const DL_Group& group, const BigInt& y,
    }
 #endif
 
-#if defined(BOTAN_HAS_DIFFIE_HELLMAN)
-/*
-* 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);
-   }
-#endif
-
 }
diff --git a/src/engine/def_engine/default_engine.h b/src/engine/def_engine/default_engine.h
index aa753fadb..918a42114 100644
--- a/src/engine/def_engine/default_engine.h
+++ b/src/engine/def_engine/default_engine.h
@@ -20,6 +20,8 @@ class Default_Engine : public Engine
    public:
       std::string provider_name() const { return "core"; }
 
+      PK_Ops::KA_Operation* get_key_agreement_op(const Private_Key&) const;
+
 #if defined(BOTAN_HAS_IF_PUBLIC_KEY_FAMILY)
       IF_Operation* if_op(const BigInt&, const BigInt&, const BigInt&,
                           const BigInt&, const BigInt&, const BigInt&,
@@ -40,10 +42,6 @@ class Default_Engine : public Engine
                             const BigInt&) const;
 #endif
 
-#if defined(BOTAN_HAS_DIFFIE_HELLMAN)
-      DH_Operation* dh_op(const DL_Group&, const BigInt&) const;
-#endif
-
       Modular_Exponentiator* mod_exp(const BigInt&,
                                      Power_Mod::Usage_Hints) const;