Botan::XMSS_Signature_Operation Class Reference

#include <xmss_signature_operation.h>

Inheritance diagram for Botan::XMSS_Signature_Operation:

Public Member Functions
AlgorithmIdentifier	algorithm_identifier () const override
std::string	hash_function () const override
std::vector< uint8_t >	sign (RandomNumberGenerator &rng) override
size_t	signature_length () const override
void	update (std::span< const uint8_t > input) override
	XMSS_Signature_Operation (const XMSS_PrivateKey &private_key)

Detailed Description

Signature generation operation for Extended Hash-Based Signatures (XMSS) as defined in:

[1] XMSS: Extended Hash-Based Signatures, Request for Comments: 8391 Release: May 2018. https://datatracker.ietf.org/doc/rfc8391/

Definition at line 29 of file xmss_signature_operation.h.

Constructor & Destructor Documentation

XMSS_Signature_Operation()

Botan::XMSS_Signature_Operation::XMSS_Signature_Operation ( const XMSS_PrivateKey & private_key )

explicit

Definition at line 23 of file xmss_signature_operation.cpp.

                                                                                     :
      m_priv_key(private_key),
      m_hash(private_key.xmss_parameters()),
      m_randomness(0),
      m_leaf_idx(0),
      m_is_initialized(false) {}

Member Function Documentation

algorithm_identifier()

AlgorithmIdentifier Botan::XMSS_Signature_Operation::algorithm_identifier ( ) const

overridevirtual

Return an algorithm identifier associated with this signature scheme.

Default implementation throws an exception

Reimplemented from Botan::PK_Ops::Signature.

Definition at line 90 of file xmss_signature_operation.cpp.

                                                                         {
   return AlgorithmIdentifier(OID::from_string("XMSS"), AlgorithmIdentifier::USE_EMPTY_PARAM);
}

References Botan::OID::from_string(), and Botan::AlgorithmIdentifier::USE_EMPTY_PARAM.

hash_function()

std::string Botan::XMSS_Signature_Operation::hash_function ( ) const

inlineoverridevirtual

Return the hash function being used by this signer

Implements Botan::PK_Ops::Signature.

Definition at line 47 of file xmss_signature_operation.h.

{ return m_hash.hash_function(); }

sign()

std::vector< uint8_t > Botan::XMSS_Signature_Operation::sign ( RandomNumberGenerator & rng )

overridevirtual

Creates an XMSS signature for the message provided through call to update().

Returns

serialized XMSS signature.

Implements Botan::PK_Ops::Signature.

Definition at line 41 of file xmss_signature_operation.cpp.

                                                                          {
   initialize();
 
   const auto msg_hash = m_hash.h_msg_final();
 
   const auto& params = m_priv_key.xmss_parameters();
   wots_keysig_t auth_path(params.tree_height());
 
   XMSS_Address adrs;
   adrs.set_type(XMSS_Address::Type::Hash_Tree_Address);
 
   for(size_t j = 0; j < params.tree_height(); j++) {
      const size_t k = (m_leaf_idx / (static_cast<size_t>(1) << j)) ^ 0x01;
      auth_path[j] = m_priv_key.tree_hash(k * (static_cast<size_t>(1) << j), j, adrs, m_hash);
   }
 
   adrs.set_type(XMSS_Address::Type::OTS_Hash_Address);
   adrs.set_ots_address(m_leaf_idx);
 
   XMSS_Signature::TreeSignature tree_sig;
   tree_sig.authentication_path = auth_path;
   tree_sig.ots_signature =
      m_priv_key.wots_private_key_for(adrs, m_hash).sign(msg_hash, m_priv_key.public_seed(), adrs, m_hash);
 
   const XMSS_Signature sig(m_leaf_idx, m_randomness, tree_sig);
   m_is_initialized = false;
   return sig.bytes();
}

References Botan::XMSS_Signature::TreeSignature::authentication_path, Botan::XMSS_Signature::bytes(), Botan::XMSS_Address::Hash_Tree_Address, Botan::XMSS_Address::OTS_Hash_Address, Botan::XMSS_Signature::TreeSignature::ots_signature, Botan::XMSS_Address::set_ots_address(), and Botan::XMSS_Address::set_type().

signature_length()

size_t Botan::XMSS_Signature_Operation::signature_length ( ) const

overridevirtual

Return an upper bound on the length of the output signature

Implements Botan::PK_Ops::Signature.

Definition at line 30 of file xmss_signature_operation.cpp.

                                                        {
   const auto& params = m_priv_key.xmss_parameters();
   return sizeof(uint64_t) +  // size of leaf index
          params.element_size() + params.len() * params.element_size() + params.tree_height() * params.element_size();
}

update()

void Botan::XMSS_Signature_Operation::update ( std::span< const uint8_t > input )

overridevirtual

Add more data to the message currently being signed

Parameters

input

the input to be hashed/signed

Implements Botan::PK_Ops::Signature.

Definition at line 36 of file xmss_signature_operation.cpp.

                                                                  {
   initialize();
   m_hash.h_msg_update(input);
}

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

• src/lib/pubkey/xmss/xmss_signature_operation.h
• src/lib/pubkey/xmss/xmss_signature_operation.cpp