Add back in blinding to RSA, RW, ElGamal, and DH.

There are multiple unsatisfactory elements to the current solution,
as compared to how blinding was previously done:

Firstly, blinding is only used in the baseline implementations; the code
using OpenSSL and GMP is not protected by blinding at all.

Secondly, at the point we need to set up blinding, there is no access
to a PRNG. Currently I am going with a quite nasty solution, of using
a private key parameter to seed a simple PRNG constructed as:
  SHA-512(TS1 || private_key_param || public_key_param || TS2)

I really want to fix both of these elements but I'm not sure how to do
so easily.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/pubkey/elgamal/elgamal.h b/src/pubkey/elgamal/elgamal.h
index dad9dbc3e..c94779e96 100644
--- a/src/pubkey/elgamal/elgamal.h
+++ b/src/pubkey/elgamal/elgamal.h
@@ -11,6 +11,7 @@
 #include <botan/dl_algo.h>
 #include <botan/numthry.h>
 #include <botan/reducer.h>
+#include <botan/blinding.h>
 #include <botan/pk_ops.h>
 
 namespace Botan {
@@ -80,6 +81,7 @@ class BOTAN_DLL ElGamal_Decryption_Operation : public PK_Ops::Decryption
    private:
       Fixed_Exponent_Power_Mod powermod_x_p;
       Modular_Reducer mod_p;
+      Blinder blinder;
    };
 
 }