Botan::XMSS_Signature Class Reference

#include <xmss_signature.h>

Classes
struct	TreeSignature

Public Member Functions
std::vector< uint8_t >	bytes () const
secure_vector< uint8_t > &	randomness ()
const secure_vector< uint8_t > &	randomness () const
void	set_randomness (secure_vector< uint8_t > randomness)
void	set_tree (XMSS_Signature::TreeSignature tree_sig)
void	set_unused_leaf_idx (size_t idx)
XMSS_Signature::TreeSignature &	tree ()
const XMSS_Signature::TreeSignature &	tree () const
size_t	unused_leaf_index () const
	XMSS_Signature (size_t leaf_idx, secure_vector< uint8_t > randomness, XMSS_Signature::TreeSignature tree_sig)
	XMSS_Signature (XMSS_Parameters::xmss_algorithm_t oid, std::span< const uint8_t > raw_sig)

Detailed Description

Helper class for marshalling an XMSS signature

Definition at line 23 of file xmss_signature.h.

Constructor & Destructor Documentation

XMSS_Signature() [1/2]

Botan::XMSS_Signature::XMSS_Signature	(	XMSS_Parameters::xmss_algorithm_t	oid,
		std::span< const uint8_t >	raw_sig )

Creates a signature from an XMSS signature method and a uint8_t sequence representing a raw signature.

Parameters

oid	XMSS signature method
raw_sig	An XMSS signature serialized using XMSS_Signature::bytes().

Definition at line 13 of file xmss_signature.cpp.

                                                                                                  :
      m_leaf_idx(0), m_randomness(0, 0x00) {
   XMSS_Parameters xmss_params(oid);
 
   if(raw_sig.size() !=
      (xmss_params.len() + xmss_params.tree_height() + 1) * xmss_params.element_size() + sizeof(uint32_t)) {
      throw Decoding_Error("XMSS signature size invalid.");
   }
 
   for(size_t i = 0; i < 4; i++) {
      m_leaf_idx = ((m_leaf_idx << 8) | raw_sig[i]);
   }
 
   if(m_leaf_idx >= xmss_params.total_number_of_signatures()) {
      throw Decoding_Error("XMSS signature leaf index out of bounds.");
   }
 
   auto begin = raw_sig.begin() + sizeof(uint32_t);
   auto end = begin + xmss_params.element_size();
   std::copy(begin, end, std::back_inserter(m_randomness));
 
   for(size_t i = 0; i < xmss_params.len(); i++) {
      begin = end;
      end = begin + xmss_params.element_size();
      m_tree_sig.ots_signature.push_back(secure_vector<uint8_t>(0));
      m_tree_sig.ots_signature.back().reserve(xmss_params.element_size());
      std::copy(begin, end, std::back_inserter(m_tree_sig.ots_signature.back()));
   }
 
   for(size_t i = 0; i < xmss_params.tree_height(); i++) {
      begin = end;
      end = begin + xmss_params.element_size();
      m_tree_sig.authentication_path.push_back(secure_vector<uint8_t>(0));
      m_tree_sig.authentication_path.back().reserve(xmss_params.element_size());
      std::copy(begin, end, std::back_inserter(m_tree_sig.authentication_path.back()));
   }
}

References Botan::XMSS_Signature::TreeSignature::authentication_path, Botan::XMSS_Parameters::element_size(), Botan::XMSS_Parameters::len(), Botan::XMSS_Signature::TreeSignature::ots_signature, Botan::XMSS_Parameters::total_number_of_signatures(), and Botan::XMSS_Parameters::tree_height().

XMSS_Signature() [2/2]

Botan::XMSS_Signature::XMSS_Signature ( size_t leaf_idx, secure_vector< uint8_t > randomness, XMSS_Signature::TreeSignature tree_sig )

inline

Creates an XMSS Signature from a leaf index used for signature generation, a random value and a tree signature.

Parameters

leaf_idx	Leaf index used to generate the signature.
randomness	A random value.
tree_sig	A tree signature.

Definition at line 50 of file xmss_signature.h.

                                                                                                               :
            m_leaf_idx(leaf_idx), m_randomness(std::move(randomness)), m_tree_sig(std::move(tree_sig)) {}

Member Function Documentation

bytes()

std::vector< uint8_t > Botan::XMSS_Signature::bytes

(

)

const

Generates a serialized representation of XMSS Signature by concatenating the following elements in order: 4-byte leaf index, n-bytes randomness, ots_signature, authentication path.

n is the element_size(), len equal to len(), h the tree height defined by the chosen XMSS signature method.

Returns

serialized signature, a sequence of 4+(len + h + 1)n bytes.

Definition at line 51 of file xmss_signature.cpp.

                                               {
   std::vector<uint8_t> result{static_cast<uint8_t>(m_leaf_idx >> 24U),
                               static_cast<uint8_t>(m_leaf_idx >> 16U),
                               static_cast<uint8_t>(m_leaf_idx >> 8U),
                               static_cast<uint8_t>(m_leaf_idx)};
 
   std::copy(m_randomness.begin(), m_randomness.end(), std::back_inserter(result));
 
   for(const auto& sig : tree().ots_signature) {
      std::copy(sig.begin(), sig.end(), std::back_inserter(result));
   }
 
   for(const auto& auth : tree().authentication_path) {
      std::copy(auth.begin(), auth.end(), std::back_inserter(result));
   }
   return result;
}

References tree().

randomness() [1/2]

secure_vector< uint8_t > & Botan::XMSS_Signature::randomness ( )

inline

Definition at line 62 of file xmss_signature.h.

{ return m_randomness; }

randomness() [2/2]

const secure_vector< uint8_t > & Botan::XMSS_Signature::randomness ( ) const

inline

Definition at line 55 of file xmss_signature.h.

{ return m_randomness; }

Referenced by set_randomness().

set_randomness()

void Botan::XMSS_Signature::set_randomness ( secure_vector< uint8_t > randomness )

inline

Definition at line 64 of file xmss_signature.h.

{ m_randomness = std::move(randomness); }

References randomness().

set_tree()

void Botan::XMSS_Signature::set_tree ( XMSS_Signature::TreeSignature tree_sig )

inline

Definition at line 68 of file xmss_signature.h.

{ m_tree_sig = std::move(tree_sig); }

set_unused_leaf_idx()

void Botan::XMSS_Signature::set_unused_leaf_idx ( size_t idx )

inline

Definition at line 60 of file xmss_signature.h.

{ m_leaf_idx = idx; }

tree() [1/2]

XMSS_Signature::TreeSignature & Botan::XMSS_Signature::tree ( )

inline

Definition at line 66 of file xmss_signature.h.

{ return m_tree_sig; }

tree() [2/2]

const XMSS_Signature::TreeSignature & Botan::XMSS_Signature::tree ( ) const

inline

Definition at line 57 of file xmss_signature.h.

{ return m_tree_sig; }

Referenced by bytes().

unused_leaf_index()

size_t Botan::XMSS_Signature::unused_leaf_index ( ) const

inline

Definition at line 53 of file xmss_signature.h.

{ return m_leaf_idx; }

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

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