Helper class used to derive secret values based in the pseudorandom key generation described in RFC 8554 Appendix A. More...

#include <hss_lms_utils.h>

Public Member Functions
template<concepts::resizable_byte_buffer T = secure_vector<uint8_t>>
T	gen (HashFunction &hash, std::span< const uint8_t > seed) const
	Create a hash value using the preconfigured prefix and a `seed`.

void	gen (std::span< uint8_t > out, HashFunction &hash, std::span< const uint8_t > seed) const
	Create a hash value using the preconfigured prefix and a `seed`.

	PseudorandomKeyGeneration (std::span< const uint8_t > identifier)
	Create a PseudorandomKeyGeneration instance for a fixed `identifier`.

void	set_i (uint16_t i)
	Specify the value for the u16str(i) hash input field.

void	set_j (uint8_t j)
	Specify the value for the u8str(j) hash input field.

void	set_q (uint32_t q)
	Specify the value for the u32str(q) hash input field.

Detailed Description

Helper class used to derive secret values based in the pseudorandom key generation described in RFC 8554 Appendix A.

This generation computes the following:

Result = Hash( identifier || u32str(q) || u16str(i) || u8str(j) || SEED )

This Key Generation procedure is also used for the seed derivation function of SECRET_METHOD 2 defined in https://github.com/cisco/hash-sigs,

Definition at line 28 of file hss_lms_utils.h.

Constructor & Destructor Documentation

◆ PseudorandomKeyGeneration()

Botan::PseudorandomKeyGeneration::PseudorandomKeyGeneration ( std::span< const uint8_t > identifier )

Create a PseudorandomKeyGeneration instance for a fixed identifier.

Definition at line 18 of file hss_lms_utils.cpp.

                                                                                      :
      m_input_buffer(identifier.size() + 7),
      m_q(std::span(m_input_buffer).last<7>().first<4>()),
      m_i(std::span(m_input_buffer).last<3>().first<2>()),
      m_j(std::span(m_input_buffer).last<1>()) {
   copy_mem(std::span(m_input_buffer).first(identifier.size()), identifier);
}

References Botan::copy_mem().

Member Function Documentation

◆ gen() [1/2]

template<concepts::resizable_byte_buffer T = secure_vector<uint8_t>>

T Botan::PseudorandomKeyGeneration::gen	(	HashFunction &	hash,
		std::span< const uint8_t >	seed ) const

inline

Create a hash value using the preconfigured prefix and a seed.

Definition at line 54 of file hss_lms_utils.h.

                                                                   {
         T output(hash.output_length());
         gen(output, hash, seed);
         return output;
      }

References gen(), Botan::Buffered_Computation::output_length(), and T.

Referenced by gen(), and Botan::LMOTS_Private_Key::LMOTS_Private_Key().

◆ gen() [2/2]

void Botan::PseudorandomKeyGeneration::gen	(	std::span< uint8_t >	out,
		HashFunction &	hash,
		std::span< const uint8_t >	seed ) const

Create a hash value using the preconfigured prefix and a seed.

Definition at line 26 of file hss_lms_utils.cpp.

                                                                                                               {
   hash.update(m_input_buffer);
   hash.update(seed);
   hash.final(out);
}

References Botan::Buffered_Computation::final(), and Botan::Buffered_Computation::update().