/*

* PBKDF1

* (C) 1999-2007 Jack Lloyd

*

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

*/

#include <botan/pbkdf1.h>

#include <botan/exceptn.h>

namespace Botan {

size_t PKCS5_PBKDF1::pbkdf(uint8_t output_buf[], size_t output_len,

                           const std::string& passphrase,

                           const uint8_t salt[], size_t salt_len,

                           size_t iterations,

                           std::chrono::milliseconds msec) const

   {

   if(output_len > m_hash->output_length())

      throw Invalid_Argument("PKCS5_PBKDF1: Requested output length too long");

   m_hash->update(passphrase);

   m_hash->update(salt, salt_len);

   secure_vector<uint8_t> key = m_hash->final();

   const auto start = std::chrono::high_resolution_clock::now();

   size_t iterations_performed = 1;

   while(true)

      {

      if(iterations == 0)

         {

         if(iterations_performed % 10000 == 0)

            {

            auto time_taken = std::chrono::high_resolution_clock::now() - start;

            auto msec_taken = std::chrono::duration_cast<std::chrono::milliseconds>(time_taken);

            if(msec_taken > msec)

               break;

            }

         }

      else if(iterations_performed == iterations)

         break;

      m_hash->update(key);

      m_hash->final(key.data());

      ++iterations_performed;

      }

   copy_mem(output_buf, key.data(), output_len);

   return iterations_performed;

   }

}