/*

* KDF1

* (C) 1999-2007 Jack Lloyd

*

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

*/

#include <botan/internal/kdf1.h>

#include <botan/exceptn.h>

namespace Botan {

std::string KDF1::name() const

   {

   return "KDF1(" + m_hash->name() + ")";

   }

std::unique_ptr<KDF> KDF1::new_object() const

   {

   return std::make_unique<KDF1>(m_hash->new_object());

   }

void KDF1::kdf(uint8_t key[], size_t key_len,

               const uint8_t secret[], size_t secret_len,

               const uint8_t salt[], size_t salt_len,

               const uint8_t label[], size_t label_len) const

   {

   if(key_len == 0)

      return;

   if(key_len > m_hash->output_length())

      throw Invalid_Argument("KDF1 maximum output length exceeeded");

   m_hash->update(secret, secret_len);

   m_hash->update(label, label_len);

   m_hash->update(salt, salt_len);

   if(key_len == m_hash->output_length())

      {

      // In this case we can hash directly into the output buffer

      m_hash->final(key);

      }

   else

      {

      // Otherwise a copy is required

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

      copy_mem(key, v.data(), key_len);

      }

   }

}