Botan  2.13.0
Crypto and TLS for C++11
rdrand_rng.h
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1 /*
2 * RDRAND RNG
3 * (C) 2016,2019 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 
16  {
17  public:
18  /**
19  * Constructor will throw if CPU does not have RDRAND bit set
20  */
21  RDRAND_RNG();
22 
23  /**
24  * Return true if RDRAND is available on the current processor
25  */
26  static bool available();
27 
28  bool accepts_input() const override { return false; }
29 
30  /**
31  * Uses RDRAND to produce output
32  */
33  void randomize(uint8_t out[], size_t out_len) override;
34 
35  /*
36  * No way to provide entropy to RDRAND generator, so add_entropy is ignored
37  */
38  void add_entropy(const uint8_t[], size_t) override
39  { /* no op */ }
40 
41  /*
42  * No way to reseed RDRAND generator, so reseed is ignored
43  */
44  size_t reseed(Entropy_Sources&, size_t, std::chrono::milliseconds) override
45  { return 0; /* no op */ }
46 
47  std::string name() const override { return "RDRAND"; }
48 
49  bool is_seeded() const override { return true; }
50 
51  /**
52  * On correctly working hardware, RDRAND is always supposed to
53  * succeed within a set number of retries. If after that many
54  * retries RDRAND has still not suceeded, sets ok = false and
55  * returns 0.
56  */
57  static uint32_t BOTAN_DEPRECATED("Use RDRAND_RNG::randomize") rdrand_status(bool& ok);
58 
59  /*
60  * Calls RDRAND until it succeeds, this could hypothetically
61  * loop forever on broken hardware.
62  */
63  static uint32_t BOTAN_DEPRECATED("Use RDRAND_RNG::randomize") rdrand();
64  };
65 
66 }
67 
68 #endif
bool is_seeded() const override
Definition: rdrand_rng.h:49
int(* final)(unsigned char *, CTX *)
#define BOTAN_PUBLIC_API(maj, min)
Definition: compiler.h:31
size_t reseed(Entropy_Sources &, size_t, std::chrono::milliseconds) override
Definition: rdrand_rng.h:44
void add_entropy(const uint8_t[], size_t) override
Definition: rdrand_rng.h:38
Definition: alg_id.cpp:13
bool accepts_input() const override
Definition: rdrand_rng.h:28
std::string name() const override
Definition: rdrand_rng.h:47