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.

1 files changed, 36 insertions, 3 deletions

diff --git a/src/pubkey/pubkey.h b/src/pubkey/pubkey.h
index 6d48faa4f..4d6490919 100644
--- a/src/pubkey/pubkey.h
+++ b/src/pubkey/pubkey.h
@@ -1,6 +1,6 @@
 /*
 * Public Key Interface
-* (C) 1999-2007 Jack Lloyd
+* (C) 1999-2010 Jack Lloyd
 *
 * Distributed under the terms of the Botan license
 */
@@ -9,6 +9,7 @@
 #define BOTAN_PUBKEY_H__
 
 #include <botan/pk_keys.h>
+#include <botan/pk_ops.h>
 #include <botan/symkey.h>
 #include <botan/rng.h>
 #include <botan/eme.h>
@@ -284,6 +285,23 @@ class BOTAN_DLL PK_Key_Agreement
       * @param in the other parties key
       * @param in_len the length of in in bytes
       * @param params extra derivation params
+      * @param params_len the length of params in bytes
+      */
+      SymmetricKey derive_key(u32bit key_len,
+                              const MemoryRegion<byte>& in,
+                              const byte params[],
+                              u32bit params_len) const
+         {
+         return derive_key(key_len, &in[0], in.size(),
+                           params, params_len);
+         }
+
+      /*
+      * Perform Key Agreement Operation
+      * @param key_len the desired key output size
+      * @param in the other parties key
+      * @param in_len the length of in in bytes
+      * @param params extra derivation params
       */
       SymmetricKey derive_key(u32bit key_len,
                               const byte in[], u32bit in_len,
@@ -294,6 +312,21 @@ class BOTAN_DLL PK_Key_Agreement
                            params.length());
          }
 
+      /*
+      * Perform Key Agreement Operation
+      * @param key_len the desired key output size
+      * @param in the other parties key
+      * @param params extra derivation params
+      */
+      SymmetricKey derive_key(u32bit key_len,
+                              const MemoryRegion<byte>& in,
+                              const std::string& params = "") const
+         {
+         return derive_key(key_len, &in[0], in.size(),
+                           reinterpret_cast<const byte*>(params.data()),
+                           params.length());
+         }
+
       /**
       * Construct a PK Key Agreement.
       * @param key the key to use
@@ -301,12 +334,12 @@ class BOTAN_DLL PK_Key_Agreement
       */
       PK_Key_Agreement(const PK_Key_Agreement_Key& key, KDF* kdf = 0);
 
-      ~PK_Key_Agreement() { delete kdf; }
+      ~PK_Key_Agreement() { delete op; delete kdf; }
    private:
       PK_Key_Agreement(const PK_Key_Agreement_Key&);
       PK_Key_Agreement& operator=(const PK_Key_Agreement&);
 
-      const PK_Key_Agreement_Key& key;
+      PK_Ops::KA_Operation* op;
       KDF* kdf;
    };