Botan  2.6.0
Crypto and TLS for C++11
rdrand_rng.h
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1 /*
2 * RDRAND RNG
3 * (C) 2016 Jack Lloyd
4 *
5 * Botan is released under the Simplified BSD License (see license.txt)
6 */
7 
8 #ifndef BOTAN_RNG_RDRAND_H_
9 #define BOTAN_RNG_RDRAND_H_
10 
11 #include <botan/rng.h>
12 
13 namespace Botan {
14 
15 class BOTAN_PUBLIC_API(2,0) RDRAND_RNG final : public Hardware_RNG
16  {
17  public:
18  /**
19  * On correctly working hardware, RDRAND is always supposed to
20  * succeed within a set number of retries. If after that many
21  * retries RDRAND has still not suceeded, sets ok = false and
22  * returns 0.
23  */
24  static uint32_t rdrand_status(bool& ok);
25 
26  /*
27  * Calls RDRAND until it succeeds, this could hypothetically
28  * loop forever on broken hardware.
29  */
30  static uint32_t rdrand();
31 
32  /**
33  * Constructor will throw if CPU does not have RDRAND bit set
34  */
35  RDRAND_RNG();
36 
37  /**
38  * Uses RDRAND to produce output
39  */
40  void randomize(uint8_t out[], size_t out_len) override;
41 
42  /*
43  * No way to provide entropy to RDRAND generator, so add_entropy is ignored
44  */
45  void add_entropy(const uint8_t[], size_t) override
46  { /* no op */ }
47 
48  /*
49  * No way to reseed RDRAND generator, so reseed is ignored
50  */
51  size_t reseed(Entropy_Sources&, size_t, std::chrono::milliseconds) override
52  { return 0; /* no op */ }
53 
54  std::string name() const override { return "RDRAND"; }
55 
56  bool is_seeded() const override { return true; }
57  };
58 
59 }
60 
61 #endif
bool is_seeded() const override
Definition: rdrand_rng.h:56
#define BOTAN_PUBLIC_API(maj, min)
Definition: compiler.h:27
size_t reseed(Entropy_Sources &, size_t, std::chrono::milliseconds) override
Definition: rdrand_rng.h:51
void add_entropy(const uint8_t[], size_t) override
Definition: rdrand_rng.h:45
Definition: alg_id.cpp:13
std::string name() const override
Definition: rdrand_rng.h:54