/src/botan/build/include/botan/reducer.h
Line | Count | Source (jump to first uncovered line) |
1 | | /* |
2 | | * Modular Reducer |
3 | | * (C) 1999-2010 Jack Lloyd |
4 | | * |
5 | | * Botan is released under the Simplified BSD License (see license.txt) |
6 | | */ |
7 | | |
8 | | #ifndef BOTAN_MODULAR_REDUCER_H_ |
9 | | #define BOTAN_MODULAR_REDUCER_H_ |
10 | | |
11 | | #include <botan/numthry.h> |
12 | | |
13 | | namespace Botan { |
14 | | |
15 | | /** |
16 | | * Modular Reducer (using Barrett's technique) |
17 | | */ |
18 | | class BOTAN_PUBLIC_API(2,0) Modular_Reducer |
19 | | { |
20 | | public: |
21 | 1.32k | const BigInt& get_modulus() const { return m_modulus; } |
22 | | |
23 | | BigInt reduce(const BigInt& x) const; |
24 | | |
25 | | /** |
26 | | * Multiply mod p |
27 | | * @param x the first operand |
28 | | * @param y the second operand |
29 | | * @return (x * y) % p |
30 | | */ |
31 | | BigInt multiply(const BigInt& x, const BigInt& y) const |
32 | 883k | { return reduce(x * y); } |
33 | | |
34 | | /** |
35 | | * Square mod p |
36 | | * @param x the value to square |
37 | | * @return (x * x) % p |
38 | | */ |
39 | | BigInt square(const BigInt& x) const |
40 | 3.99M | { return reduce(Botan::square(x)); } |
41 | | |
42 | | /** |
43 | | * Cube mod p |
44 | | * @param x the value to cube |
45 | | * @return (x * x * x) % p |
46 | | */ |
47 | | BigInt cube(const BigInt& x) const |
48 | 0 | { return multiply(x, this->square(x)); } |
49 | | |
50 | | /** |
51 | | * Low level reduction function. Mostly for internal use. |
52 | | * Sometimes useful for performance by reducing temporaries |
53 | | * Reduce x mod p and place the output in out. ** X and out must not reference each other ** |
54 | | * ws is a temporary workspace. |
55 | | */ |
56 | | void reduce(BigInt& out, const BigInt& x, secure_vector<word>& ws) const; |
57 | | |
58 | 0 | bool initialized() const { return (m_mod_words != 0); } |
59 | | |
60 | 0 | Modular_Reducer() { m_mod_words = 0; } |
61 | | explicit Modular_Reducer(const BigInt& mod); |
62 | | private: |
63 | | BigInt m_modulus, m_mu; |
64 | | size_t m_mod_words; |
65 | | }; |
66 | | |
67 | | } |
68 | | |
69 | | #endif |