salsa20.h

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/*
* Salsa20 / XSalsa20
* (C) 1999-2010 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
 
#ifndef BOTAN_SALSA20_H__
#define BOTAN_SALSA20_H__
 
#include <botan/stream_cipher.h>
 
namespace Botan {
 
/**
* DJB's Salsa20 (and XSalsa20)
*/
class BOTAN_DLL Salsa20 : public StreamCipher
   {
   public:
      void cipher(const byte in[], byte out[], size_t length);
 
      void set_iv(const byte iv[], size_t iv_len);
 
      bool valid_iv_length(size_t iv_len) const
         { return (iv_len == 8 || iv_len == 24); }
 
      Key_Length_Specification key_spec() const
         {
         return Key_Length_Specification(16, 32, 16);
         }
 
      void clear();
      std::string name() const;
      StreamCipher* clone() const { return new Salsa20; }
 
      Salsa20() : state(16), buffer(64), position(0) {}
   private:
      void key_schedule(const byte key[], size_t key_len);
 
      SecureVector<u32bit> state;
      SecureVector<byte> buffer;
      size_t position;
   };
 
}
 
#endif