/*
* Salsa20 / XSalsa20
* (C) 1999-2010 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_SALSA20_H__
#define BOTAN_SALSA20_H__

#include <botan/stream_cipher.h>

namespace Botan {

/**
* DJB's Salsa20 (and XSalsa20)
*/
class BOTAN_DLL Salsa20 final : public StreamCipher
   {
   public:
      void cipher(const uint8_t in[], uint8_t out[], size_t length) override;

      void set_iv(const uint8_t iv[], size_t iv_len) override;

      bool valid_iv_length(size_t iv_len) const override
         { return (iv_len == 0 || iv_len == 8 || iv_len == 24); }

      Key_Length_Specification key_spec() const override
         {
         return Key_Length_Specification(16, 32, 16);
         }

      void clear() override;
      std::string name() const override;
      StreamCipher* clone() const override { return new Salsa20; }

      void seek(uint64_t offset) override;
   private:
      void key_schedule(const uint8_t key[], size_t key_len) override;

      secure_vector<uint32_t> m_state;
      secure_vector<uint8_t> m_buffer;
      size_t m_position = 0;
   };

}

#endif