Botan  1.11.15
Public Member Functions | Static Public Member Functions
Botan::ANSI_X931_RNG Class Reference

#include <x931_rng.h>

Inheritance diagram for Botan::ANSI_X931_RNG:
Botan::RandomNumberGenerator

List of all members.

Public Member Functions

void add_entropy (const byte[], size_t)
 ANSI_X931_RNG (BlockCipher *cipher, RandomNumberGenerator *rng)
void clear ()
bool is_seeded () const
std::string name () const
byte next_byte ()
virtual secure_vector< byterandom_vec (size_t bytes)
void randomize (byte[], size_t)
void reseed (size_t poll_bits)

Static Public Member Functions

static RandomNumberGeneratormake_rng ()

Detailed Description

ANSI X9.31 RNG

Definition at line 19 of file x931_rng.h.


Constructor & Destructor Documentation

Parameters:
cipherthe block cipher to use in this PRNG
rngthe underlying PRNG for generating inputs (eg, an HMAC_RNG)

Definition at line 108 of file x931_rng.cpp.

                                                          :
   m_cipher(cipher),
   m_prng(prng),
   m_R(m_cipher->block_size()),
   m_R_pos(0)
   {
   }

Member Function Documentation

void Botan::ANSI_X931_RNG::add_entropy ( const byte  in[],
size_t  length 
) [virtual]

Add entropy to this RNG.

Parameters:
ina byte array containg the entropy to be added
lengththe length of the byte array in

Implements Botan::RandomNumberGenerator.

Definition at line 82 of file x931_rng.cpp.

   {
   m_prng->add_entropy(input, length);
   rekey();
   }
void Botan::ANSI_X931_RNG::clear ( ) [virtual]

Clear all internally held values of this RNG.

Implements Botan::RandomNumberGenerator.

Definition at line 93 of file x931_rng.cpp.

References Botan::zeroise().

   {
   m_cipher->clear();
   m_prng->clear();
   zeroise(m_R);
   m_V.clear();

   m_R_pos = 0;
   }
bool Botan::ANSI_X931_RNG::is_seeded ( ) const [virtual]

Check whether this RNG is seeded.

Returns:
true if this RNG was already seeded, false otherwise.

Implements Botan::RandomNumberGenerator.

Definition at line 88 of file x931_rng.cpp.

Referenced by randomize().

   {
   return (m_V.size() > 0);
   }

Create a seeded and active RNG object for general application use Added in 1.8.0

Definition at line 14 of file rng.cpp.

   {
   std::unique_ptr<RandomNumberGenerator> rng(
      new HMAC_RNG(make_a<MessageAuthenticationCode>("HMAC(SHA-512)"),
                   make_a<MessageAuthenticationCode>("HMAC(SHA-256)"))
      );

   rng->reseed(256);

   return rng.release();
   }
std::string Botan::ANSI_X931_RNG::name ( ) const [virtual]

Return the name of this object

Implements Botan::RandomNumberGenerator.

Definition at line 103 of file x931_rng.cpp.

Referenced by randomize().

   {
   return "X9.31(" + m_cipher->name() + ")";
   }

Return a random byte

Returns:
random byte

Definition at line 53 of file rng.h.

Referenced by Botan::random_prime().

         {
         byte out;
         this->randomize(&out, 1);
         return out;
         }
virtual secure_vector<byte> Botan::RandomNumberGenerator::random_vec ( size_t  bytes) [inline, virtual, inherited]
void Botan::ANSI_X931_RNG::randomize ( byte  output[],
size_t  length 
) [virtual]

Randomize a byte array.

Parameters:
outputthe byte array to hold the random output.
lengththe length of the byte array output.

Implements Botan::RandomNumberGenerator.

Definition at line 14 of file x931_rng.cpp.

References Botan::copy_mem(), is_seeded(), name(), and reseed().

   {
   if(!is_seeded())
      {
      reseed(BOTAN_RNG_RESEED_POLL_BITS);

      if(!is_seeded())
         throw PRNG_Unseeded(name());
      }

   while(length)
      {
      if(m_R_pos == m_R.size())
         update_buffer();

      const size_t copied = std::min<size_t>(length, m_R.size() - m_R_pos);

      copy_mem(out, &m_R[m_R_pos], copied);
      out += copied;
      length -= copied;
      m_R_pos += copied;
      }
   }
void Botan::ANSI_X931_RNG::reseed ( size_t  bits_to_collect) [virtual]

Seed this RNG using the entropy sources it contains.

Parameters:
bits_to_collectis the number of bits of entropy to attempt to gather from the entropy sources

Implements Botan::RandomNumberGenerator.

Definition at line 76 of file x931_rng.cpp.

Referenced by randomize().

   {
   m_prng->reseed(poll_bits);
   rekey();
   }

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