Botan  1.10.9
gmp_powm.cpp
Go to the documentation of this file.
1 /*
2 * GMP Modular Exponentiation
3 * (C) 1999-2007 Jack Lloyd
4 *
5 * Distributed under the terms of the Botan license
6 */
7 
8 #include <botan/internal/gnump_engine.h>
9 #include <botan/internal/gmp_wrap.h>
10 
11 namespace Botan {
12 
13 namespace {
14 
15 /*
16 * GMP Modular Exponentiator
17 */
18 class GMP_Modular_Exponentiator : public Modular_Exponentiator
19  {
20  public:
21  void set_base(const BigInt& b) { base = b; }
22  void set_exponent(const BigInt& e) { exp = e; }
23  BigInt execute() const;
24  Modular_Exponentiator* copy() const
25  { return new GMP_Modular_Exponentiator(*this); }
26 
27  GMP_Modular_Exponentiator(const BigInt& n) : mod(n) {}
28  private:
29  GMP_MPZ base, exp, mod;
30  };
31 
32 /*
33 * Compute the result
34 */
35 BigInt GMP_Modular_Exponentiator::execute() const
36  {
37  GMP_MPZ r;
38  mpz_powm(r.value, base.value, exp.value, mod.value);
39  return r.to_bigint();
40  }
41 
42 }
43 
44 /*
45 * Return the GMP-based modular exponentiator
46 */
49  {
50  return new GMP_Modular_Exponentiator(n);
51  }
52 
53 }
BigInt n
Definition: numthry.cpp:26
GMP_MPZ exp
Definition: gmp_powm.cpp:29
GMP_MPZ mod
Definition: gmp_powm.cpp:29
mpz_t value
Definition: gmp_wrap.h:22
Modular_Exponentiator * mod_exp(const BigInt &, Power_Mod::Usage_Hints) const
Definition: gmp_powm.cpp:47
BigInt r
Definition: numthry.cpp:26
GMP_MPZ base
Definition: gmp_powm.cpp:29