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
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
/*
* RandomNumberGenerator
* (C) 1999-2009 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_RANDOM_NUMBER_GENERATOR_H__
#define BOTAN_RANDOM_NUMBER_GENERATOR_H__
#include <botan/secmem.h>
#include <botan/exceptn.h>
#include <chrono>
#include <string>
#include <mutex>
namespace Botan {
class Entropy_Sources;
/**
* This class represents a random number (RNG) generator object.
*/
class BOTAN_DLL RandomNumberGenerator
{
public:
/**
* Create a seeded and active RNG object for general application use
* Added in 1.8.0
*/
static RandomNumberGenerator* make_rng();
/**
* Randomize a byte array.
* @param output the byte array to hold the random output.
* @param length the length of the byte array output.
*/
virtual void randomize(byte output[], size_t length) = 0;
/**
* Return a random vector
* @param bytes number of bytes in the result
* @return randomized vector of length bytes
*/
virtual secure_vector<byte> random_vec(size_t bytes)
{
secure_vector<byte> output(bytes);
randomize(output.data(), output.size());
return output;
}
/**
* Only usable with POD types, only useful with integers
* get_random<u64bit>()
*/
template<typename T> T get_random()
{
T r;
this->randomize(reinterpret_cast<byte*>(&r), sizeof(r));
return r;
}
/**
* Return a value in range [0,2^bits)
*/
u64bit gen_mask(size_t bits)
{
if(bits == 0 || bits > 64)
throw Invalid_Argument("RandomNumberGenerator::gen_mask invalid argument");
const u64bit mask = ((1 << bits) - 1);
return this->get_random<u64bit>() & mask;
}
/**
* Return a random byte
* @return random byte
*/
byte next_byte() { return get_random<byte>(); }
byte next_nonzero_byte()
{
byte b = next_byte();
while(b == 0)
b = next_byte();
return b;
}
/**
* Check whether this RNG is seeded.
* @return true if this RNG was already seeded, false otherwise.
*/
virtual bool is_seeded() const = 0;
/**
* Clear all internally held values of this RNG.
*/
virtual void clear() = 0;
/**
* Return the name of this object
*/
virtual std::string name() const = 0;
/**
* Seed this RNG using the global entropy sources and default timeout
* @param bits_to_collect is the number of bits of entropy to
attempt to gather from the entropy sources
*/
size_t reseed(size_t bits_to_collect);
/**
* Seed this RNG using the global entropy sources
* @param bits_to_collect is the number of bits of entropy to
attempt to gather from the entropy sources
* @param poll_timeout try not to run longer than this, no matter what
*/
size_t reseed_with_timeout(size_t bits_to_collect,
std::chrono::milliseconds poll_timeout);
/**
* Poll provided sources for up to poll_bits bits of entropy
* or until the timeout expires. Returns estimate of the number
* of bits collected.
*/
virtual size_t reseed_with_sources(Entropy_Sources& srcs,
size_t poll_bits,
std::chrono::milliseconds poll_timeout) = 0;
/**
* Add entropy to this RNG.
* @param in a byte array containg the entropy to be added
* @param length the length of the byte array in
*/
virtual void add_entropy(const byte in[], size_t length) = 0;
/*
* Never copy a RNG, create a new one
*/
RandomNumberGenerator(const RandomNumberGenerator& rng) = delete;
RandomNumberGenerator& operator=(const RandomNumberGenerator& rng) = delete;
RandomNumberGenerator() {}
virtual ~RandomNumberGenerator() {}
};
/**
* Null/stub RNG - fails if you try to use it for anything
*/
class BOTAN_DLL Null_RNG : public RandomNumberGenerator
{
public:
void randomize(byte[], size_t) override { throw PRNG_Unseeded("Null_RNG"); }
void clear() override {}
std::string name() const override { return "Null_RNG"; }
size_t reseed_with_sources(Entropy_Sources&, size_t,
std::chrono::milliseconds) override
{
return 0;
}
bool is_seeded() const override { return false; }
void add_entropy(const byte[], size_t) override {}
};
/**
* Wraps access to a RNG in a mutex
*/
class BOTAN_DLL Serialized_RNG : public RandomNumberGenerator
{
public:
void randomize(byte out[], size_t len) override
{
std::lock_guard<std::mutex> lock(m_mutex);
m_rng->randomize(out, len);
}
bool is_seeded() const override
{
std::lock_guard<std::mutex> lock(m_mutex);
return m_rng->is_seeded();
}
void clear() override
{
std::lock_guard<std::mutex> lock(m_mutex);
m_rng->clear();
}
std::string name() const override
{
std::lock_guard<std::mutex> lock(m_mutex);
return m_rng->name();
}
size_t reseed_with_sources(Entropy_Sources& src,
size_t bits,
std::chrono::milliseconds msec) override
{
std::lock_guard<std::mutex> lock(m_mutex);
return m_rng->reseed_with_sources(src, bits, msec);
}
void add_entropy(const byte in[], size_t len) override
{
std::lock_guard<std::mutex> lock(m_mutex);
m_rng->add_entropy(in, len);
}
Serialized_RNG() : m_rng(RandomNumberGenerator::make_rng()) {}
Serialized_RNG(RandomNumberGenerator* rng) : m_rng(rng) {}
private:
mutable std::mutex m_mutex;
std::unique_ptr<RandomNumberGenerator> m_rng;
};
}
#endif
|
