Botan  2.1.0
Crypto and TLS for C++11
Public Member Functions | Static Public Member Functions | List of all members
Botan::Intel_Rdseed Class Referencefinal

#include <rdseed.h>

Inheritance diagram for Botan::Intel_Rdseed:
Botan::Entropy_Source

Public Member Functions

std::string name () const override
 
size_t poll (RandomNumberGenerator &rng) override
 

Static Public Member Functions

static std::unique_ptr< Entropy_Sourcecreate (const std::string &type)
 

Detailed Description

Entropy source using the rdseed instruction first introduced on Intel's Broadwell architecture.

Definition at line 19 of file rdseed.h.

Member Function Documentation

std::unique_ptr< Entropy_Source > Botan::Entropy_Source::create ( const std::string &  type)
staticinherited

Return a new entropy source of a particular type, or null Each entropy source may require substantial resources (eg, a file handle or socket instance), so try to share them among multiple RNGs, or just use the preconfigured global list accessed by Entropy_Sources::global_sources()

Definition at line 45 of file entropy_srcs.cpp.

Referenced by Botan::Entropy_Sources::Entropy_Sources().

46  {
47  if(name == "rdrand")
48  {
49 #if defined(BOTAN_HAS_ENTROPY_SRC_RDRAND)
50  return std::unique_ptr<Entropy_Source>(new Intel_Rdrand);
51 #endif
52  }
53 
54  if(name == "rdseed")
55  {
56 #if defined(BOTAN_HAS_ENTROPY_SRC_RDSEED)
57  return std::unique_ptr<Entropy_Source>(new Intel_Rdseed);
58 #endif
59  }
60 
61  if(name == "darwin_secrandom")
62  {
63 #if defined(BOTAN_HAS_ENTROPY_SRC_DARWIN_SECRANDOM)
64  return std::unique_ptr<Entropy_Source>(new Darwin_SecRandom);
65 #endif
66  }
67 
68  if(name == "getentropy")
69  {
70 #if defined(BOTAN_HAS_ENTROPY_SRC_GETENTROPY)
71  return std::unique_ptr<Entropy_Source>(new Getentropy);
72 #endif
73  }
74 
75  if(name == "dev_random")
76  {
77 #if defined(BOTAN_HAS_ENTROPY_SRC_DEV_RANDOM)
78  return std::unique_ptr<Entropy_Source>(new Device_EntropySource(BOTAN_SYSTEM_RNG_POLL_DEVICES));
79 #endif
80  }
81 
82  if(name == "win32_cryptoapi")
83  {
84 #if defined(BOTAN_HAS_ENTROPY_SRC_CAPI)
85  return std::unique_ptr<Entropy_Source>(new Win32_CAPI_EntropySource("RSA_FULL"));
86 #endif
87  }
88 
89  if(name == "proc_walk")
90  {
91 #if defined(BOTAN_HAS_ENTROPY_SRC_PROC_WALKER)
92  const std::string root_dir = BOTAN_ENTROPY_PROC_FS_PATH;
93  if(!root_dir.empty())
94  return std::unique_ptr<Entropy_Source>(new ProcWalking_EntropySource(root_dir));
95 #endif
96  }
97 
98  if(name == "system_stats")
99  {
100 #if defined(BOTAN_HAS_ENTROPY_SRC_WIN32)
101  return std::unique_ptr<Entropy_Source>(new Win32_EntropySource);
102 #endif
103  }
104 
105  return std::unique_ptr<Entropy_Source>();
106  }
virtual std::string name() const =0
std::string Botan::Intel_Rdseed::name ( ) const
inlineoverridevirtual
Returns
name identifying this entropy source

Implements Botan::Entropy_Source.

Definition at line 22 of file rdseed.h.

22 { return "rdseed"; }
size_t Botan::Intel_Rdseed::poll ( RandomNumberGenerator rng)
overridevirtual

Perform an entropy gathering poll

Parameters
rngwill be provided with entropy via calls to add_entropy
Returns
conservative estimate of actual entropy added to rng during poll

Implements Botan::Entropy_Source.

Definition at line 19 of file rdseed.cpp.

19  {
20  if(CPUID::has_rdseed())
21  {
22  for(size_t p = 0; p != BOTAN_ENTROPY_INTEL_RNG_POLLS; ++p)
23  {
24  for(size_t i = 0; i != BOTAN_ENTROPY_RDSEED_RETRIES; ++i)
25  {
26  uint32_t r = 0;
27 
28 #if defined(BOTAN_USE_GCC_INLINE_ASM)
29  int cf = 0;
30 
31  // Encoding of rdseed %eax
32  asm(".byte 0x0F, 0xC7, 0xF8; adcl $0,%1" :
33  "=a" (r), "=r" (cf) : "0" (r), "1" (cf) : "cc");
34 #else
35  int cf = _rdseed32_step(&r);
36 #endif
37  if(1 == cf)
38  {
39  rng.add_entropy_T(r);
40  break;
41  }
42  }
43  }
44  }
45 
46  return 0;
47  }

The documentation for this class was generated from the following files: