/*

 * XMSS WOTS Private Key

 * A Winternitz One Time Signature private key for use with Extended Hash-Based

 * Signatures.

 *

 * (C) 2016,2017 Matthias Gierlings

 *

 * Botan is released under the Simplified BSD License (see license.txt)

 **/

#include <botan/xmss_wots.h>

#include <botan/internal/xmss_tools.h>

#include <botan/internal/xmss_address.h>

namespace Botan {

wots_keysig_t

XMSS_WOTS_PrivateKey::generate(const secure_vector<uint8_t>& priv_seed,

                               XMSS_Hash& hash)

   {

   wots_keysig_t priv_key(m_wots_params.len(),

                          secure_vector<uint8_t>(0));

   for(size_t i = 0; i < m_wots_params.len(); i++)

      {

      XMSS_Tools::concat<size_t>(priv_key[i], i, 32);

      hash.prf(priv_key[i], priv_seed, priv_key[i]);

      }

   return priv_key;

   }

XMSS_WOTS_PublicKey

XMSS_WOTS_PrivateKey::generate_public_key(XMSS_Address& adrs)

   {

   XMSS_WOTS_PublicKey pub_key(m_wots_params.oid(),

                               public_seed());

   generate_public_key(pub_key, wots_keysig_t((*this)[adrs]), adrs);

   return pub_key;

   }

void

XMSS_WOTS_PrivateKey::generate_public_key(XMSS_WOTS_PublicKey& pub_key,

                                          wots_keysig_t&& in_key_data,

                                          XMSS_Address& adrs,

                                          XMSS_Hash& hash)

   {

   BOTAN_ASSERT(wots_parameters() == pub_key.wots_parameters() &&

                public_seed() == pub_key.public_seed(),

                "Conflicting public key data.");

   pub_key.set_key_data(std::move(in_key_data));

   for(size_t i = 0; i < m_wots_params.len(); i++)

      {

      adrs.set_chain_address(static_cast<uint32_t>(i));

      chain(pub_key[i], 0, m_wots_params.wots_parameter() - 1, adrs,

            public_seed(), hash);

      }

   }

wots_keysig_t

XMSS_WOTS_PrivateKey::sign(const secure_vector<uint8_t>& msg,

                           XMSS_Address& adrs,

                           XMSS_Hash& hash)

   {

   secure_vector<uint8_t> msg_digest

      {

      m_wots_params.base_w(msg, m_wots_params.len_1())

      };

   m_wots_params.append_checksum(msg_digest);

   wots_keysig_t sig(this->at(adrs, hash));

   for(size_t i = 0; i < m_wots_params.len(); i++)

      {

      adrs.set_chain_address(static_cast<uint32_t>(i));

      chain(sig[i], 0 , msg_digest[i], adrs, m_public_seed, hash);

      }

   return sig;

   }

wots_keysig_t XMSS_WOTS_PrivateKey::at(const XMSS_Address& adrs, XMSS_Hash& hash)

   {

   secure_vector<uint8_t> result;

   hash.prf(result, m_private_seed, adrs.bytes());

   return generate(result, hash);

   }

wots_keysig_t XMSS_WOTS_PrivateKey::at(size_t i, XMSS_Hash& hash)

   {

   secure_vector<uint8_t> idx_bytes;

   XMSS_Tools::concat(idx_bytes, i, m_wots_params.element_size());

   hash.h(idx_bytes, m_private_seed, idx_bytes);

   return generate(idx_bytes, hash);

   }

}