/*

 * XMSS Signature

 * (C) 2016 Matthias Gierlings

 *

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

 **/

#ifndef BOTAN_XMSS_SIGNATURE_H_

#define BOTAN_XMSS_SIGNATURE_H_

#include <cstddef>

#include <botan/exceptn.h>

#include <botan/types.h>

#include <botan/secmem.h>

#include <botan/xmss_parameters.h>

#include <botan/xmss_wots.h>

namespace Botan {

/**

 * Helper class for marshalling an XMSS signature

 */

class XMSS_Signature final

   {

   public:

      /**

       * Creates a signature from an XMSS signature method and a uint8_t sequence

       * representing a raw signature.

       *

       * @param oid XMSS signature method

       * @param raw_sig An XMSS signature serialized using

       *                XMSS_Signature::bytes().

       **/

      XMSS_Signature(XMSS_Parameters::xmss_algorithm_t oid,

                     const secure_vector<uint8_t>& raw_sig);

      /**

       * Creates an XMSS Signature from a leaf index used for signature

       * generation, a random value and a tree signature.

       *

       * @param leaf_idx Leaf index used to generate the signature.

       * @param randomness A random value.

       * @param tree_sig A tree signature.

       **/

      XMSS_Signature(size_t leaf_idx,

                     secure_vector<uint8_t> randomness,

                     XMSS_WOTS_PublicKey::TreeSignature tree_sig)

         : m_leaf_idx(leaf_idx), m_randomness(std::move(randomness)),

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

      size_t unused_leaf_index() const { return m_leaf_idx; }

      void set_unused_leaf_idx(size_t idx) { m_leaf_idx = idx; }

      const secure_vector<uint8_t> randomness() const

         {

         return m_randomness;

         }

      secure_vector<uint8_t>& randomness()

         {

         return m_randomness;

         }

      void set_randomness(secure_vector<uint8_t> randomness)

         {

         m_randomness = std::move(randomness);

         }

      const XMSS_WOTS_PublicKey::TreeSignature& tree() const

         {

         return m_tree_sig;

         }

      XMSS_WOTS_PublicKey::TreeSignature& tree()

         {

         return m_tree_sig;

         }

      void set_tree(XMSS_WOTS_PublicKey::TreeSignature tree_sig)

         {

         m_tree_sig = std::move(tree_sig);

         }

      /**

       * 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.

       *

       * @return serialized signature, a sequence of

       *         4+(len + h + 1)n bytes.

       **/

      secure_vector<uint8_t> bytes() const;

   private:

      size_t m_leaf_idx;

      secure_vector<uint8_t> m_randomness;

      XMSS_WOTS_PublicKey::TreeSignature m_tree_sig;

   };

}

#endif