blob: b45e0e1864e440202f0acb60ce92125ac0b3bfcb (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
/*
* Modular Reducer
* (C) 1999-2010 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_MODULAR_REDUCER_H__
#define BOTAN_MODULAR_REDUCER_H__
#include <botan/numthry.h>
namespace Botan {
/**
* Modular Reducer (using Barrett's technique)
*/
class BOTAN_DLL Modular_Reducer
{
public:
const BigInt& get_modulus() const { return modulus; }
BigInt reduce(const BigInt& x) const;
/**
* Multiply mod p
* @param x
* @param y
* @return (x * y) % p
*/
BigInt multiply(const BigInt& x, const BigInt& y) const
{ return reduce(x * y); }
/**
* Square mod p
* @param x
* @return (x * x) % p
*/
BigInt square(const BigInt& x) const
{ return reduce(Botan::square(x)); }
/**
* Cube mod p
* @param x
* @return (x * x * x) % p
*/
BigInt cube(const BigInt& x) const
{ return multiply(x, this->square(x)); }
bool initialized() const { return (mod_words != 0); }
Modular_Reducer() { mod_words = 0; }
Modular_Reducer(const BigInt& mod);
private:
BigInt modulus, modulus_2, mu;
size_t mod_words;
};
}
#endif
|
