Botan::Polyval Class Reference

#include <polyval.h>

Inheritance diagram for Botan::Polyval:

Public Member Functions
void	clear () override
void	final (std::span< uint8_t, BS > out)
	Write the current state to out, and reset the state.
bool	has_keying_material () const override
Key_Length_Specification	key_spec () const override
size_t	maximum_keylength () const
size_t	minimum_keylength () const
std::string	name () const override
std::string	provider () const
void	set_key (const OctetString &key)
void	set_key (const uint8_t key[], size_t length)
void	set_key (std::span< const uint8_t > key)
void	update (std::span< const uint8_t > input)
bool	valid_keylength (size_t length) const
void	zero_pad ()
	Zero pad the input to a multiple of the block size.

Protected Member Functions
void	assert_key_material_set () const
void	assert_key_material_set (bool predicate) const

Detailed Description

POLYVAL universal hash (RFC 8452), used by AES-GCM-SIV

This is not a secure MAC; it must only be used as a component of a construction (like GCM-SIV) which encrypts its output.

Definition at line 21 of file polyval.h.

Member Function Documentation

assert_key_material_set() [1/2]

void Botan::SymmetricAlgorithm::assert_key_material_set ( ) const

inlineprotectedinherited

Throw Key_Not_Set unless a key has been set on this object

Definition at line 180 of file sym_algo.h.

{ assert_key_material_set(has_keying_material()); }

References assert_key_material_set(), and has_keying_material().

Referenced by assert_key_material_set(), Botan::Salsa20::cipher_bytes(), Botan::Lion::decrypt_n(), Botan::Lion::encrypt_n(), Botan::GHASH::final(), Botan::Polyval::final(), Botan::Salsa20::generate_keystream(), Botan::GHASH::nonce_hash(), Botan::GHASH::reset_associated_data(), Botan::ChaCha::seek(), Botan::CTR_BE::seek(), Botan::Salsa20::seek(), Botan::GHASH::set_associated_data(), Botan::OCB_Mode::set_associated_data_n(), Botan::Salsa20::set_iv_bytes(), Botan::GHASH::update(), Botan::Polyval::update(), Botan::GHASH::update_associated_data(), and Botan::Polyval::zero_pad().

assert_key_material_set() [2/2]

void Botan::SymmetricAlgorithm::assert_key_material_set ( bool predicate ) const

inlineprotectedinherited

Throw Key_Not_Set unless the predicate holds

Parameters

predicate

if false, a Key_Not_Set exception is thrown

Definition at line 186 of file sym_algo.h.

                                                         {
         if(!predicate) {
            throw_key_not_set_error();
         }
      }

clear()

void Botan::Polyval::clear ( )

overridevirtual

Reset the internal state. This includes not just the key, but any partial message that may have been in process.

Implements Botan::SymmetricAlgorithm.

Definition at line 141 of file polyval.cpp.

                    {
   zap(m_HM);
   zap(m_H_pow);
   secure_scrub_memory(m_state);
   m_buffer.clear();
}

References Botan::secure_scrub_memory(), and Botan::zap().

final()

void Botan::Polyval::final

(

std::span< uint8_t, BS >

out

)

Write the current state to out, and reset the state.

Definition at line 127 of file polyval.cpp.

                                            {
   assert_key_material_set();
   BOTAN_STATE_CHECK(m_buffer.in_alignment());
 
   if(m_H_pow.empty()) {
      // Fallback path; the state is in the GHASH byte order
      copy_mem(out, byte_reverse(m_state));
   } else {
      copy_mem(out, m_state);
   }
 
   secure_scrub_memory(m_state);
}

References Botan::SymmetricAlgorithm::assert_key_material_set(), BOTAN_STATE_CHECK, Botan::copy_mem(), and Botan::secure_scrub_memory().

has_keying_material()

bool Botan::Polyval::has_keying_material ( ) const

overridevirtual

Test whether a key has been set on this object

Returns

true if a key has been set on this object

Implements Botan::SymmetricAlgorithm.

Definition at line 51 of file polyval.cpp.

                                        {
   return !m_HM.empty() || !m_H_pow.empty();
}

key_spec()

Key_Length_Specification Botan::Polyval::key_spec ( ) const

inlineoverridevirtual

Return the key lengths supported by this algorithm

Returns

object describing limits on key size

Implements Botan::SymmetricAlgorithm.

Definition at line 34 of file polyval.h.

{ return Key_Length_Specification(BS); }

maximum_keylength()

size_t Botan::SymmetricAlgorithm::maximum_keylength ( ) const

inlineinherited

Return the largest acceptable key length

Returns

maximum allowed key length

Definition at line 130 of file sym_algo.h.

{ return key_spec().maximum_keylength(); }

References key_spec().

minimum_keylength()

size_t Botan::SymmetricAlgorithm::minimum_keylength ( ) const

inlineinherited

Return the smallest acceptable key length

Returns

minimum allowed key length

Definition at line 136 of file sym_algo.h.

{ return key_spec().minimum_keylength(); }

References key_spec().

name()

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

inlineoverridevirtual

Return the name of this algorithm

Returns

the algorithm name

Implements Botan::SymmetricAlgorithm.

Definition at line 40 of file polyval.h.

{ return "Polyval"; }

provider()

std::string Botan::Polyval::provider

(

)

const

Definition at line 29 of file polyval.cpp.

                                  {
#if defined(BOTAN_HAS_GHASH_AVX512_CLMUL)
   if(auto feat = CPUID::check(CPUID::Feature::AVX512_CLMUL)) {
      return *feat;
   }
#endif
 
#if defined(BOTAN_HAS_GHASH_CLMUL_CPU)
   if(auto feat = CPUID::check(CPUID::Feature::HW_CLMUL)) {
      return *feat;
   }
#endif
 
#if defined(BOTAN_HAS_GHASH_CLMUL_VPERM)
   if(auto feat = CPUID::check(CPUID::Feature::SIMD_4X32)) {
      return *feat;
   }
#endif
 
   return "base";
}

References Botan::CPUFeature::AVX512_CLMUL, Botan::CPUID::check(), Botan::CPUFeature::HW_CLMUL, and Botan::CPUFeature::SIMD_4X32.

set_key() [1/3]

void Botan::SymmetricAlgorithm::set_key ( const OctetString & key )

inherited

Set the symmetric key of this object.

Parameters

key	the SymmetricKey to be set.

Definition at line 14 of file sym_algo.cpp.

                                                       {
   set_key(std::span{key.begin(), key.length()});
}

References Botan::OctetString::begin(), Botan::OctetString::length(), and set_key().

Referenced by Botan::create_aes_row_generator(), Botan::Sodium::crypto_stream_salsa20(), Botan::Sodium::crypto_stream_salsa20_xor_ic(), Botan::Sodium::crypto_stream_xsalsa20(), Botan::Sodium::crypto_stream_xsalsa20_xor_ic(), Botan::FPE::fe1_decrypt(), Botan::FPE::fe1_encrypt(), Botan::Sphincs_Hash_Functions_Sha2::PRF_msg(), Botan::Sodium::randombytes_buf_deterministic(), Botan::TLS::TLS_NULL_HMAC_AEAD_Mode::reset(), and set_key().

set_key() [2/3]

void Botan::SymmetricAlgorithm::set_key ( const uint8_t key[], size_t length )

inlineinherited

Set the symmetric key of this object.

Parameters

key	the to be set as a byte array.
length	in bytes of key param

Definition at line 162 of file sym_algo.h.

{ set_key(std::span{key, length}); }

References set_key().

Referenced by set_key().

set_key() [3/3]

void Botan::SymmetricAlgorithm::set_key ( std::span< const uint8_t > key )

inherited

Set the symmetric key of this object.

Parameters

key	the contiguous byte range to be set.

Definition at line 22 of file sym_algo.cpp.

                                                           {
   if(!valid_keylength(key.size())) {
      throw Invalid_Key_Length(name(), key.size());
   }
   key_schedule(key);
}

References name(), and valid_keylength().

update()

void Botan::Polyval::update

(

std::span< const uint8_t >

input

)

Definition at line 101 of file polyval.cpp.

                                                 {
   assert_key_material_set();
   BufferSlicer in(input);
   while(!in.empty()) {
      if(const auto one_block = m_buffer.handle_unaligned_data(in)) {
         polyval_multiply(m_state, one_block.value(), 1);
      }
 
      if(m_buffer.in_alignment()) {
         const auto [aligned_data, full_blocks] = m_buffer.aligned_data_to_process(in);
         if(full_blocks > 0) {
            polyval_multiply(m_state, aligned_data, full_blocks);
         }
      }
   }
   BOTAN_ASSERT_NOMSG(in.empty());
}

References Botan::SymmetricAlgorithm::assert_key_material_set(), BOTAN_ASSERT_NOMSG, and Botan::BufferSlicer::empty().

valid_keylength()

bool Botan::SymmetricAlgorithm::valid_keylength ( size_t length ) const

inlineinherited

Check whether a given key length is valid for this algorithm.

Parameters

length

the key length to be checked.

Returns

true if the key length is valid.

Definition at line 143 of file sym_algo.h.

{ return key_spec().valid_keylength(length); }

References key_spec().

Referenced by set_key().

zero_pad()

void Botan::Polyval::zero_pad

(

)

Zero pad the input to a multiple of the block size.

Definition at line 119 of file polyval.cpp.

                       {
   assert_key_material_set();
   if(!m_buffer.in_alignment()) {
      m_buffer.fill_up_with_zeros();
      polyval_multiply(m_state, m_buffer.consume(), 1);
   }
}

References Botan::SymmetricAlgorithm::assert_key_material_set().

---

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

• src/lib/utils/ghash/polyval/polyval.h
• src/lib/utils/ghash/polyval/polyval.cpp