Botan::Getentropy Class Reference

#include <getentropy.h>

Inheritance diagram for Botan::Getentropy:

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

Static Public Member Functions
static std::unique_ptr< Entropy_Source >	create (std::string_view type)

Detailed Description

Entropy source using the getentropy(2) system call first introduced in OpenBSD 5.6 and added to Solaris 11.3.

Definition at line 19 of file getentropy.h.

Member Function Documentation

create()

std::unique_ptr< Entropy_Source > Botan::Entropy_Source::create ( std::string_view  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 88 of file entropy_srcs.cpp.

                                                                        {
#if defined(BOTAN_HAS_SYSTEM_RNG)
   if(name == "system_rng") {
      return std::make_unique<System_RNG_EntropySource>();
   }
#endif
 
#if defined(BOTAN_HAS_PROCESSOR_RNG)
   if(name == "hwrng") {
      if(Processor_RNG::available()) {
         return std::make_unique<Processor_RNG_EntropySource>();
      }
   }
#endif
 
#if defined(BOTAN_HAS_ENTROPY_SRC_RDSEED)
   if(name == "rdseed") {
      return std::make_unique<Intel_Rdseed>();
   }
#endif
 
#if defined(BOTAN_HAS_ENTROPY_SRC_GETENTROPY)
   if(name == "getentropy") {
      return std::make_unique<Getentropy>();
   }
#endif
 
#if defined(BOTAN_HAS_ENTROPY_SRC_WIN32)
   if(name == "system_stats") {
      return std::make_unique<Win32_EntropySource>();
   }
#endif
 
   BOTAN_UNUSED(name);
   return nullptr;
}

References Botan::Processor_RNG::available(), BOTAN_UNUSED, and Botan::Entropy_Source::name().

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

name()

std::string Botan::Getentropy::name ( ) const

inlineoverridevirtual

Returns

name identifying this entropy source

Implements Botan::Entropy_Source.

Definition at line 21 of file getentropy.h.

{ return "getentropy"; }

poll()

size_t Botan::Getentropy::poll ( RandomNumberGenerator &  rng )

overridevirtual

Gather 256 bytes entropy from getentropy(2). Note that maximum buffer size is limited to 256 bytes. On OpenBSD this does neither block nor fail.

Implements Botan::Entropy_Source.

Definition at line 23 of file getentropy.cpp.

                                                  {
   secure_vector<uint8_t> buf(256);
 
   if(::getentropy(buf.data(), buf.size()) == 0) {
      rng.add_entropy(buf.data(), buf.size());
      return buf.size() * 8;
   }
 
   return 0;
}

References Botan::RandomNumberGenerator::add_entropy().

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

• src/lib/entropy/getentropy/getentropy.h
• src/lib/entropy/getentropy/getentropy.cpp