Botan  2.15.0
Crypto and TLS for C++11
Static Public Member Functions | List of all members
Botan::XMSS_Common_Ops Class Reference

#include <xmss_common_ops.h>

Static Public Member Functions

static void create_l_tree (secure_vector< uint8_t > &result, wots_keysig_t pk, XMSS_Address &adrs, const secure_vector< uint8_t > &seed, XMSS_Hash &hash, const XMSS_Parameters &params)
 
static void randomize_tree_hash (secure_vector< uint8_t > &result, const secure_vector< uint8_t > &left, const secure_vector< uint8_t > &right, XMSS_Address &adrs, const secure_vector< uint8_t > &seed, XMSS_Hash &hash, const XMSS_Parameters &params)
 

Detailed Description

Operations shared by XMSS signature generation and verification operations.

Definition at line 26 of file xmss_common_ops.h.

Member Function Documentation

◆ create_l_tree()

void Botan::XMSS_Common_Ops::create_l_tree ( secure_vector< uint8_t > &  result,
wots_keysig_t  pk,
XMSS_Address adrs,
const secure_vector< uint8_t > &  seed,
XMSS_Hash hash,
const XMSS_Parameters params 
)
static

Algorithm 8: "ltree" Create an L-tree used to compute the leaves of the binary hash tree. Takes a WOTS+ public key and compresses it to a single n-byte value.

This overload is used in multithreaded scenarios, where it is required to provide seperate instances of XMSS_Hash to each thread.

Parameters
[out]resultPublic key compressed to a single n-byte value pk[0].
[in]pkWinternitz One Time Signatures+ public key.
[in]adrsAddress encoding the address of the L-Tree
[in]seedThe seed generated during the public key generation.
[in]hashInstance of XMSS_Hash, that may only be used by the thead executing create_l_tree.

Definition at line 47 of file xmss_common_ops.cpp.

References Botan::XMSS_Address::get_tree_height(), hash, Botan::XMSS_Parameters::len(), randomize_tree_hash(), Botan::XMSS_Address::set_tree_height(), and Botan::XMSS_Address::set_tree_index().

53  {
54  size_t l = params.len();
55  adrs.set_tree_height(0);
56 
57  while(l > 1)
58  {
59  for(size_t i = 0; i < l >> 1; i++)
60  {
61  adrs.set_tree_index(static_cast<uint32_t>(i));
62  randomize_tree_hash(pk[i], pk[2 * i], pk[2 * i + 1], adrs, seed, hash, params);
63  }
64  if(l & 0x01)
65  {
66  pk[l >> 1] = pk[l - 1];
67  }
68  l = (l >> 1) + (l & 0x01);
69  adrs.set_tree_height(adrs.get_tree_height() + 1);
70  }
71  result = pk[0];
72  }
static void randomize_tree_hash(secure_vector< uint8_t > &result, const secure_vector< uint8_t > &left, const secure_vector< uint8_t > &right, XMSS_Address &adrs, const secure_vector< uint8_t > &seed, XMSS_Hash &hash, const XMSS_Parameters &params)
MechanismType hash

◆ randomize_tree_hash()

void Botan::XMSS_Common_Ops::randomize_tree_hash ( secure_vector< uint8_t > &  result,
const secure_vector< uint8_t > &  left,
const secure_vector< uint8_t > &  right,
XMSS_Address adrs,
const secure_vector< uint8_t > &  seed,
XMSS_Hash hash,
const XMSS_Parameters params 
)
static

Algorithm 7: "RAND_HASH"

Generates a randomized hash.

This overload is used in multithreaded scenarios, where it is required to provide seperate instances of XMSS_Hash to each thread.

Parameters
[out]resultThe resulting randomized hash.
[in]leftLeft half of the hash function input.
[in]rightRight half of the hash function input.
[in]adrsAdress of the hash function call.
[in]seedThe seed for G.
[in]hashInstance of XMSS_Hash, that may only by the thead executing generate_public_key.

Definition at line 14 of file xmss_common_ops.cpp.

References BOTAN_ASSERT, Botan::XMSS_Address::bytes(), Botan::XMSS_Parameters::element_size(), hash, Botan::XMSS_Address::Key_Mode, Botan::XMSS_Address::Mask_LSB_Mode, Botan::XMSS_Address::Mask_MSB_Mode, and Botan::XMSS_Address::set_key_mask_mode().

Referenced by create_l_tree(), and Botan::XMSS_PrivateKey::tree_hash().

21  {
22  adrs.set_key_mask_mode(XMSS_Address::Key_Mask::Key_Mode);
23  secure_vector<uint8_t> key { hash.prf(seed, adrs.bytes()) };
24 
25  adrs.set_key_mask_mode(XMSS_Address::Key_Mask::Mask_MSB_Mode);
26  secure_vector<uint8_t> bitmask_l { hash.prf(seed, adrs.bytes()) };
27 
28  adrs.set_key_mask_mode(XMSS_Address::Key_Mask::Mask_LSB_Mode);
29  secure_vector<uint8_t> bitmask_r { hash.prf(seed, adrs.bytes()) };
30 
31  BOTAN_ASSERT(bitmask_l.size() == left.size() &&
32  bitmask_r.size() == right.size(),
33  "Bitmask size doesn't match node size.");
34 
35  secure_vector<uint8_t> concat_xor(params.element_size() * 2);
36  for(size_t i = 0; i < left.size(); i++)
37  {
38  concat_xor[i] = left[i] ^ bitmask_l[i];
39  concat_xor[i + left.size()] = right[i] ^ bitmask_r[i];
40  }
41 
42  hash.h(result, key, concat_xor);
43  }
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:55
MechanismType hash

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