1 files changed, 91 insertions, 0 deletions
diff --git a/src/math/numbertheory/pow_mod.h b/src/math/numbertheory/pow_mod.h
new file mode 100644
index 000000000..37e0871da
--- /dev/null
+++ b/src/math/numbertheory/pow_mod.h
@@ -0,0 +1,91 @@
+/*************************************************
+* Modular Exponentiator Header File              *
+* (C) 1999-2007 Jack Lloyd                       *
+*************************************************/
+
+#ifndef BOTAN_POWER_MOD_H__
+#define BOTAN_POWER_MOD_H__
+
+#include <botan/bigint.h>
+
+namespace Botan {
+
+/*************************************************
+* Modular Exponentiator Interface                *
+*************************************************/
+class BOTAN_DLL Modular_Exponentiator
+   {
+   public:
+      virtual void set_base(const BigInt&) = 0;
+      virtual void set_exponent(const BigInt&) = 0;
+      virtual BigInt execute() const = 0;
+      virtual Modular_Exponentiator* copy() const = 0;
+      virtual ~Modular_Exponentiator() {}
+   };
+
+/*************************************************
+* Modular Exponentiator Proxy                    *
+*************************************************/
+class BOTAN_DLL Power_Mod
+   {
+   public:
+      enum Usage_Hints {
+         NO_HINTS        = 0x0000,
+
+         BASE_IS_FIXED   = 0x0001,
+         BASE_IS_SMALL   = 0x0002,
+         BASE_IS_LARGE   = 0x0004,
+         BASE_IS_2       = 0x0008,
+
+         EXP_IS_FIXED    = 0x0100,
+         EXP_IS_SMALL    = 0x0200,
+         EXP_IS_LARGE    = 0x0400
+      };
+
+      void set_modulus(const BigInt&, Usage_Hints = NO_HINTS) const;
+      void set_base(const BigInt&) const;
+      void set_exponent(const BigInt&) const;
+
+      BigInt execute() const;
+
+      Power_Mod& operator=(const Power_Mod&);
+
+      Power_Mod(const BigInt& = 0, Usage_Hints = NO_HINTS);
+      Power_Mod(const Power_Mod&);
+      ~Power_Mod();
+   private:
+      mutable Modular_Exponentiator* core;
+      Usage_Hints hints;
+   };
+
+/*************************************************
+* Fixed Exponent Modular Exponentiator Proxy     *
+*************************************************/
+class BOTAN_DLL Fixed_Exponent_Power_Mod : public Power_Mod
+   {
+   public:
+      BigInt operator()(const BigInt& b) const
+         { set_base(b); return execute(); }
+
+      Fixed_Exponent_Power_Mod() {}
+      Fixed_Exponent_Power_Mod(const BigInt&, const BigInt&,
+                               Usage_Hints = NO_HINTS);
+   };
+
+/*************************************************
+* Fixed Base Modular Exponentiator Proxy         *
+*************************************************/
+class BOTAN_DLL Fixed_Base_Power_Mod : public Power_Mod
+   {
+   public:
+      BigInt operator()(const BigInt& e) const
+         { set_exponent(e); return execute(); }
+
+      Fixed_Base_Power_Mod() {}
+      Fixed_Base_Power_Mod(const BigInt&, const BigInt&,
+                           Usage_Hints = NO_HINTS);
+   };
+
+}
+
+#endif