blob: 96ffcad0b3b0fdf132a31a80c49fbe1d7b0b0aa1 (
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
62
63
64
65
66
67
68
69
70
|
/**
* EntropySource Header File
* (C) 2008-2009 Jack Lloyd
*/
#ifndef BOTAN_ENTROPY_SOURCE_BASE_H__
#define BOTAN_ENTROPY_SOURCE_BASE_H__
#include <botan/buf_comp.h>
#include <string>
#include <utility>
namespace Botan {
/**
* Class used to accumulate the poll results of EntropySources
*/
class Entropy_Accumulator
{
public:
Entropy_Accumulator(BufferedComputation& sink, u32bit goal) :
entropy_sink(sink), entropy_goal(goal), collected_bits(0) {}
/**
@return cached I/O buffer for repeated polls
*/
MemoryRegion<byte>& get_io_buffer(u32bit size)
{ io_buffer.create(size); return io_buffer; }
u32bit bits_collected() const { return collected_bits; }
bool polling_goal_achieved() const
{ return (collected_bits >= entropy_goal); }
u32bit desired_remaining_bits() const
{
return (collected_bits >= entropy_goal) ? 0 : (entropy_goal - collected_bits);
}
void add(const void* bytes, u32bit length, double entropy_bits_per_byte)
{
entropy_sink.update(reinterpret_cast<const byte*>(bytes), length);
collected_bits += std::min<u32bit>(8, entropy_bits_per_byte) * length;
}
template<typename T>
void add(const T& v, double entropy_bits_per_byte)
{
add(&v, sizeof(T), entropy_bits_per_byte);
}
private:
BufferedComputation& entropy_sink;
SecureVector<byte> io_buffer;
u32bit entropy_goal, collected_bits;
};
/**
* Abstract interface to a source of (hopefully unpredictable) system entropy
*/
class BOTAN_DLL EntropySource
{
public:
virtual std::string name() const = 0;
virtual void poll(Entropy_Accumulator& accum) = 0;
virtual ~EntropySource() {}
};
}
#endif
|
