#include <auto_rng.h>

Inheritance diagram for Botan::AutoSeeded_RNG:

Public Member Functions
bool	accepts_input () const override

void	add_entropy (const uint8_t in[], size_t len) override

template<typename T >
void	add_entropy_T (const T &t)

	AutoSeeded_RNG (Entropy_Sources &entropy_sources, size_t reseed_interval=BOTAN_RNG_DEFAULT_RESEED_INTERVAL)

	AutoSeeded_RNG (RandomNumberGenerator &underlying_rng, Entropy_Sources &entropy_sources, size_t reseed_interval=BOTAN_RNG_DEFAULT_RESEED_INTERVAL)

	AutoSeeded_RNG (RandomNumberGenerator &underlying_rng, size_t reseed_interval=BOTAN_RNG_DEFAULT_RESEED_INTERVAL)

	AutoSeeded_RNG (size_t reseed_interval=BOTAN_RNG_DEFAULT_RESEED_INTERVAL)

void	clear () override

void	force_reseed ()

bool	is_seeded () const override

std::string	name () const override

uint8_t	next_byte ()

uint8_t	next_nonzero_byte ()

secure_vector< uint8_t >	random_vec (size_t bytes)

template<typename Alloc >
void	random_vec (std::vector< uint8_t, Alloc > &v, size_t bytes)

void	randomize (uint8_t out[], size_t len) override

void	randomize_with_input (uint8_t output[], size_t output_len, const uint8_t input[], size_t input_len) override

virtual void	randomize_with_ts_input (uint8_t output[], size_t output_len)

size_t	reseed (Entropy_Sources &srcs, size_t poll_bits=BOTAN_RNG_RESEED_POLL_BITS, std::chrono::milliseconds poll_timeout=BOTAN_RNG_RESEED_DEFAULT_TIMEOUT) override

virtual void	reseed_from_rng (RandomNumberGenerator &rng, size_t poll_bits=BOTAN_RNG_RESEED_POLL_BITS)

	~AutoSeeded_RNG ()

Detailed Description

A userspace PRNG

Definition at line 20 of file auto_rng.h.

Constructor & Destructor Documentation

◆ AutoSeeded_RNG() [1/4]

Botan::AutoSeeded_RNG::AutoSeeded_RNG ( size_t reseed_interval = BOTAN_RNG_DEFAULT_RESEED_INTERVAL )

Uses the system RNG (if available) or else a default group of entropy sources (all other systems) to gather seed material.

Parameters

reseed_interval specifies a limit of how many times the RNG will be called before automatic reseeding is performed

Definition at line 54 of file auto_rng.cpp.

                                                     :
#if defined(BOTAN_HAS_SYSTEM_RNG)
   AutoSeeded_RNG(system_rng(), reseed_interval)
#else
   AutoSeeded_RNG(Entropy_Sources::global_sources(), reseed_interval)
#endif
   {
   }

◆ AutoSeeded_RNG() [2/4]

Botan::AutoSeeded_RNG::AutoSeeded_RNG	(	RandomNumberGenerator &	underlying_rng,
		size_t	reseed_interval = `BOTAN_RNG_DEFAULT_RESEED_INTERVAL`
	)

Create an AutoSeeded_RNG which will get seed material from some other RNG instance. For example you could provide a reference to the system RNG or a hardware RNG.

Parameters

underlying_rng	is a reference to some RNG which will be used to perform the periodic reseeding
reseed_interval	specifies a limit of how many times the RNG will be called before automatic reseeding is performed

Definition at line 26 of file auto_rng.cpp.

   {
   m_rng.reset(new HMAC_DRBG(MessageAuthenticationCode::create_or_throw(BOTAN_AUTO_RNG_HMAC),
                             underlying_rng,
                             reseed_interval));
   force_reseed();
   }

References BOTAN_AUTO_RNG_HMAC, Botan::MessageAuthenticationCode::create_or_throw(), and force_reseed().

◆ AutoSeeded_RNG() [3/4]

Botan::AutoSeeded_RNG::AutoSeeded_RNG	(	Entropy_Sources &	entropy_sources,
		size_t	reseed_interval = `BOTAN_RNG_DEFAULT_RESEED_INTERVAL`
	)

Create an AutoSeeded_RNG which will get seed material from a set of entropy sources.

Parameters

entropy_sources	will be polled to perform reseeding periodically
reseed_interval	specifies a limit of how many times the RNG will be called before automatic reseeding is performed

Definition at line 35 of file auto_rng.cpp.

   {
   m_rng.reset(new HMAC_DRBG(MessageAuthenticationCode::create_or_throw(BOTAN_AUTO_RNG_HMAC),
                             entropy_sources,
                             reseed_interval));
   force_reseed();
   }

References BOTAN_AUTO_RNG_HMAC, Botan::MessageAuthenticationCode::create_or_throw(), and force_reseed().

◆ AutoSeeded_RNG() [4/4]

Botan::AutoSeeded_RNG::AutoSeeded_RNG	(	RandomNumberGenerator &	underlying_rng,
		Entropy_Sources &	entropy_sources,
		size_t	reseed_interval = `BOTAN_RNG_DEFAULT_RESEED_INTERVAL`
	)

Create an AutoSeeded_RNG which will get seed material from both an underlying RNG and a set of entropy sources.

Parameters

underlying_rng	is a reference to some RNG which will be used to perform the periodic reseeding
entropy_sources	will be polled to perform reseeding periodically
reseed_interval	specifies a limit of how many times the RNG will be called before automatic reseeding is performed

Definition at line 44 of file auto_rng.cpp.

   {
   m_rng.reset(new HMAC_DRBG(
                  MessageAuthenticationCode::create_or_throw(BOTAN_AUTO_RNG_HMAC),
                  underlying_rng, entropy_sources, reseed_interval));
   force_reseed();
   }

References BOTAN_AUTO_RNG_HMAC, Botan::MessageAuthenticationCode::create_or_throw(), and force_reseed().

◆ ~AutoSeeded_RNG()

Botan::AutoSeeded_RNG::~AutoSeeded_RNG ( )

Definition at line 21 of file auto_rng.cpp.

   {
   // for unique_ptr
   }

Member Function Documentation

◆ accepts_input()

bool Botan::AutoSeeded_RNG::accepts_input ( ) const

inlineoverridevirtual

Returns false if it is known that this RNG object is not able to accept externally provided inputs (via add_entropy, randomize_with_input, etc). In this case, any such provided inputs are ignored.

If this function returns true, then inputs may or may not be accepted.

Implements Botan::RandomNumberGenerator.

Definition at line 30 of file auto_rng.h.

30{ return true; }

◆ add_entropy()

void Botan::AutoSeeded_RNG::add_entropy	(	const uint8_t	input[],
		size_t	length
	)

overridevirtual

Incorporate some additional data into the RNG state. For example adding nonces or timestamps from a peer's protocol message can help hedge against VM state rollback attacks. A few RNG types do not accept any externally provided input, in which case this function is a no-op.

Parameters

input	a byte array containg the entropy to be added
length	the length of the byte array in

Exceptions

Exception may throw if the RNG accepts input, but adding the entropy failed.

Implements Botan::RandomNumberGenerator.

Definition at line 89 of file auto_rng.cpp.

   {
   m_rng->add_entropy(in, len);
   }

◆ add_entropy_T()

template<typename T >

void Botan::RandomNumberGenerator::add_entropy_T ( const T & t )

inlineinherited

Incorporate some additional data into the RNG state.

Definition at line 76 of file rng.h.

         {
         static_assert(std::is_standard_layout<T>::value && std::is_trivial<T>::value, "add_entropy_T data must be POD");
         this->add_entropy(reinterpret_cast<const uint8_t*>(&t), sizeof(T));
         }

References T.

Referenced by Botan::Win32_EntropySource::poll().

◆ clear()

void Botan::AutoSeeded_RNG::clear ( )

overridevirtual

Clear all internally held values of this RNG

Postcondition: is_seeded() == false if the RNG has an internal state that can be cleared.

Implements Botan::RandomNumberGenerator.

Definition at line 79 of file auto_rng.cpp.

   {
   m_rng->clear();
   }

◆ force_reseed()

void Botan::AutoSeeded_RNG::force_reseed ( )

Mark state as requiring a reseed on next use

Definition at line 63 of file auto_rng.cpp.

   {
   m_rng->force_reseed();
   m_rng->next_byte();
 
   if(!m_rng->is_seeded())
      {
      throw Internal_Error("AutoSeeded_RNG reseeding failed");
      }
   }

Referenced by AutoSeeded_RNG().

◆ is_seeded()

bool Botan::AutoSeeded_RNG::is_seeded ( ) const

overridevirtual

Check whether this RNG is seeded.

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

Implements Botan::RandomNumberGenerator.

Definition at line 74 of file auto_rng.cpp.

   {
   return m_rng->is_seeded();
   }

◆ name()

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

overridevirtual

Returns: the name of this RNG type

Implements Botan::RandomNumberGenerator.

Definition at line 84 of file auto_rng.cpp.

   {
   return m_rng->name();
   }

◆ next_byte()

uint8_t Botan::RandomNumberGenerator::next_byte ( )

inlineinherited

Return a random byte

Returns: random byte

Exceptions

PRNG_Unseeded	if the RNG fails because it has not enough entropy
Exception	if the RNG fails

Definition at line 187 of file rng.h.

         {
         uint8_t b;
         this->randomize(&b, 1);
         return b;
         }

References b.

Referenced by Botan::random_prime().

◆ next_nonzero_byte()

uint8_t Botan::RandomNumberGenerator::next_nonzero_byte ( )

inlineinherited

Returns: a random byte that is greater than zero

Exceptions

PRNG_Unseeded	if the RNG fails because it has not enough entropy
Exception	if the RNG fails

Definition at line 199 of file rng.h.

         {
         uint8_t b = this->next_byte();
         while(b == 0)
            b = this->next_byte();
         return b;
         }

References b.

Referenced by Botan::EME_PKCS1v15::pad().

◆ random_vec() [1/2]

secure_vector< uint8_t > Botan::RandomNumberGenerator::random_vec ( size_t bytes )

inlineinherited

Return a random vector

Parameters

bytes number of bytes in the result

Returns: randomized vector of length bytes

Exceptions

PRNG_Unseeded	if the RNG fails because it has not enough entropy
Exception	if the RNG fails

Definition at line 167 of file rng.h.

         {
         secure_vector<uint8_t> output;
         random_vec(output, bytes);
         return output;
         }

Referenced by Botan::CECPQ1_accept(), Botan::CECPQ1_offer(), Botan::TLS::Client_Key_Exchange::Client_Key_Exchange(), Botan::Curve25519_PrivateKey::Curve25519_PrivateKey(), Botan::PK_Decryptor::decrypt_or_random(), Botan::Ed25519_PrivateKey::Ed25519_PrivateKey(), Botan::TLS::Session::encrypt(), Botan::KeyPair::encryption_consistency_check(), Botan::generate_bcrypt(), Botan::Kyber_PrivateKey::Kyber_PrivateKey(), Botan::OctetString::OctetString(), Botan::BigInt::randomize(), and Botan::TLS::Session_Manager_In_Memory::remove_all().

◆ random_vec() [2/2]

template<typename Alloc >

void Botan::RandomNumberGenerator::random_vec	(	std::vector< uint8_t, Alloc > &	v,
		size_t	bytes
	)

inlineinherited

Definition at line 175 of file rng.h.

         {
         v.resize(bytes);
         this->randomize(v.data(), v.size());
         }

References v.

◆ randomize()

void Botan::AutoSeeded_RNG::randomize	(	uint8_t	output[],
		size_t	length
	)

overridevirtual

Randomize a byte array.

May block shortly if e.g. the RNG is not yet initialized or a retry because of insufficient entropy is needed.

Parameters

output	the byte array to hold the random output.
length	the length of the byte array output in bytes.

Exceptions

PRNG_Unseeded	if the RNG fails because it has not enough entropy
Exception	if the RNG fails

Implements Botan::RandomNumberGenerator.

Definition at line 101 of file auto_rng.cpp.

   {
   m_rng->randomize_with_ts_input(output, output_len);
   }

◆ randomize_with_input()

void Botan::AutoSeeded_RNG::randomize_with_input	(	uint8_t	output[],
		size_t	output_len,
		const uint8_t	input[],
		size_t	input_len
	)

overridevirtual

Incorporate entropy into the RNG state then produce output. Some RNG types implement this using a single operation, default calls add_entropy + randomize in sequence.

Use this to further bind the outputs to your current process/protocol state. For instance if generating a new key for use in a session, include a session ID or other such value. See NIST SP 800-90 A, B, C series for more ideas.

Parameters

output	buffer to hold the random output
output_len	size of the output buffer in bytes
input	entropy buffer to incorporate
input_len	size of the input buffer in bytes

Exceptions

PRNG_Unseeded	if the RNG fails because it has not enough entropy
Exception	if the RNG fails
Exception	may throw if the RNG accepts input, but adding the entropy failed.

Reimplemented from Botan::RandomNumberGenerator.

Definition at line 106 of file auto_rng.cpp.

   {
   m_rng->randomize_with_input(output, output_len, ad, ad_len);
   }

◆ randomize_with_ts_input()

void Botan::RandomNumberGenerator::randomize_with_ts_input	(	uint8_t	output[],
		size_t	output_len
	)

virtualinherited

This calls randomize_with_input using some timestamps as extra input.

For a stateful RNG using non-random but potentially unique data the extra input can help protect against problems with fork, VM state rollback, or other cases where somehow an RNG state is duplicated. If both of the duplicated RNG states later incorporate a timestamp (and the timestamps don't themselves repeat), their outputs will diverge.

Parameters

output	buffer to hold the random output
output_len	size of the output buffer in bytes

Exceptions

PRNG_Unseeded	if the RNG fails because it has not enough entropy
Exception	if the RNG fails
Exception	may throw if the RNG accepts input, but adding the entropy failed.

Reimplemented in Botan::Stateful_RNG.

Definition at line 18 of file rng.cpp.

   {
   if(this->accepts_input())
      {
      /*
      Form additional input which is provided to the PRNG implementation
      to paramaterize the KDF output.
      */
      uint8_t additional_input[16] = { 0 };
      store_le(OS::get_system_timestamp_ns(), additional_input);
      store_le(OS::get_high_resolution_clock(), additional_input + 8);
 
      this->randomize_with_input(output, output_len, additional_input, sizeof(additional_input));
      }
   else
      {
      this->randomize(output, output_len);
      }
   }

References Botan::RandomNumberGenerator::accepts_input(), Botan::OS::get_high_resolution_clock(), Botan::OS::get_system_timestamp_ns(), Botan::RandomNumberGenerator::randomize(), Botan::RandomNumberGenerator::randomize_with_input(), and Botan::store_le().

◆ reseed()

size_t Botan::AutoSeeded_RNG::reseed	(	Entropy_Sources &	srcs,
		size_t	poll_bits = `BOTAN_RNG_RESEED_POLL_BITS`,
		std::chrono::milliseconds	poll_timeout = `BOTAN_RNG_RESEED_DEFAULT_TIMEOUT`
	)

overridevirtual

Poll provided sources for up to poll_bits bits of entropy or until the timeout expires. Returns estimate of the number of bits collected.

Sets the seeded state to true if enough entropy was added.

Reimplemented from Botan::RandomNumberGenerator.

Definition at line 94 of file auto_rng.cpp.

   {
   return m_rng->reseed(srcs, poll_bits, poll_timeout);
   }

◆ reseed_from_rng()

void Botan::RandomNumberGenerator::reseed_from_rng	(	RandomNumberGenerator &	rng,
		size_t	poll_bits = `BOTAN_RNG_RESEED_POLL_BITS`
	)

virtualinherited

Reseed by reading specified bits from the RNG

Sets the seeded state to true if enough entropy was added.

Exceptions

Exception if RNG accepts input but reseeding failed.

Reimplemented in Botan::Stateful_RNG.

Definition at line 59 of file rng.cpp.

   {
   if(this->accepts_input())
      {
      secure_vector<uint8_t> buf(poll_bits / 8);
      rng.randomize(buf.data(), buf.size());
      this->add_entropy(buf.data(), buf.size());
      }
   }

References Botan::RandomNumberGenerator::accepts_input(), Botan::RandomNumberGenerator::add_entropy(), and Botan::RandomNumberGenerator::randomize().

Referenced by botan_rng_reseed(), botan_rng_reseed_from_rng(), and Botan::Stateful_RNG::reseed_from_rng().

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

src/lib/rng/auto_rng/auto_rng.h
src/lib/rng/auto_rng/auto_rng.cpp

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ AutoSeeded_RNG() [1/4]

◆ AutoSeeded_RNG() [2/4]

◆ AutoSeeded_RNG() [3/4]

◆ AutoSeeded_RNG() [4/4]

◆ ~AutoSeeded_RNG()

Member Function Documentation

◆ accepts_input()

◆ add_entropy()

◆ add_entropy_T()

◆ clear()

◆ force_reseed()

◆ is_seeded()

◆ name()

◆ next_byte()

◆ next_nonzero_byte()

◆ random_vec() [1/2]

◆ random_vec() [2/2]

◆ randomize()

◆ randomize_with_input()

◆ randomize_with_ts_input()

◆ reseed()

◆ reseed_from_rng()