Botan  2.18.1
Crypto and TLS for C++11
xmss_wots_publickey.cpp
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1 /*
2  * XMSS WOTS Public Key
3  * A Winternitz One Time Signature public key for use with Extended Hash-Based
4  * Signatures.
5  *
6  * (C) 2016,2017,2018 Matthias Gierlings
7  *
8  * Botan is released under the Simplified BSD License (see license.txt)
9  **/
10 
11 #include <botan/xmss_wots.h>
12 #include <botan/internal/xmss_address.h>
13 
14 namespace Botan {
15 
16 void
18  size_t start_idx,
19  size_t steps,
20  XMSS_Address& adrs,
21  const secure_vector<uint8_t>& seed,
22  XMSS_Hash& hash)
23  {
24  secure_vector<uint8_t> prf_output(hash.output_length());
25 
26  for(size_t i = start_idx;
27  i < (start_idx + steps) && i < m_wots_params.wots_parameter();
28  i++)
29  {
30  adrs.set_hash_address(static_cast<uint32_t>(i));
31 
32  //Calculate tmp XOR bitmask
34  hash.prf(prf_output, seed, adrs.bytes());
35  xor_buf(result, prf_output, result.size());
36 
37  // Calculate key
39 
40  //Calculate f(key, tmp XOR bitmask)
41  hash.prf(prf_output, seed, adrs.bytes());
42  hash.f(result, prf_output, result);
43  }
44  }
45 
47 XMSS_WOTS_PublicKey::pub_key_from_signature(const secure_vector<uint8_t>& msg,
48  const wots_keysig_t& sig,
49  XMSS_Address& adrs,
50  const secure_vector<uint8_t>& seed)
51  {
52  secure_vector<uint8_t> msg_digest
53  {
55  };
56 
57  m_wots_params.append_checksum(msg_digest);
58  wots_keysig_t result(sig);
59 
60  for(size_t i = 0; i < m_wots_params.len(); i++)
61  {
62  adrs.set_chain_address(static_cast<uint32_t>(i));
63  chain(result[i],
64  msg_digest[i],
65  m_wots_params.wots_parameter() - 1 - msg_digest[i],
66  adrs,
67  seed);
68  }
69  return result;
70  }
71 
72 }
size_t len_1() const
Definition: xmss_wots.h:97
secure_vector< uint8_t > base_w(const secure_vector< uint8_t > &msg, size_t out_size) const
void chain(secure_vector< uint8_t > &x, size_t start_idx, size_t steps, XMSS_Address &adrs, const secure_vector< uint8_t > &public_seed, XMSS_Hash &hash)
const secure_vector< uint8_t > & bytes() const
Definition: xmss_address.h:322
void xor_buf(uint8_t out[], const uint8_t in[], size_t length)
Definition: mem_ops.h:262
Definition: alg_id.cpp:13
void set_chain_address(uint32_t value)
Definition: xmss_address.h:220
std::vector< secure_vector< uint8_t > > wots_keysig_t
void append_checksum(secure_vector< uint8_t > &data)
void set_key_mask_mode(Key_Mask value)
Definition: xmss_address.h:134
size_t wots_parameter() const
Definition: xmss_wots.h:93
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:65
void set_hash_address(uint32_t value)
Definition: xmss_address.h:282
MechanismType hash
XMSS_WOTS_Parameters m_wots_params
Definition: xmss_wots.h:427