ceasar.h File Reference

Ceasar crypto protocol. More...

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Functions
void	pok_protocols_ceasar_unmarshall (void *crypted_data, pok_size_t crypted_size, void *uncrypted_data, size_t *uncrypted_size)
void	pok_protocols_ceasar_marshall (void *uncrypted_data, pok_size_t uncrypted_size, void *crypted_data, size_t *crypted_size)

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Detailed Description

Ceasar crypto protocol.

Author:

Julien Delange

Date:

2009 This is a very basic crypto protocol that just change the order of bytes in data. There is no public/private key, the algorithm is known by the attacker so that it's a very weak crypto protocol. Interested people can gather more information about this protocol on: http://en.wikipedia.org/wiki/Caesar_cipher

We don't provide an associated marshalling type for the Ceasar protocol since the crypted size is the same than the uncrypted size.

Definition in file ceasar.h.

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Function Documentation

void pok_protocols_ceasar_marshall	(	void *	uncrypted_data,
		pok_size_t	uncrypted_size,
		void *	crypted_data,
		size_t *	crypted_size
	)

Function that encrypts data

\file libpok/protocols/ceasar.c \brief Function to crypt/uncrypt data using the Ceasar cipher. \author Julien Delange \brief Marshall data, the crypted size has the same size than uncrypted data.

Definition at line 34 of file ceasar.c.

{
   uint8_t* uncrypted;
   uint8_t* crypted;
   size_t   tmp;

   uncrypted   = (uint8_t*) uncrypted_data;
   crypted     = (uint8_t*) crypted_data;

   for (tmp = 0 ; tmp < uncrypted_size ; tmp++)
   {
         crypted[tmp] = (uncrypted[tmp] + 4) % 255;
   }

   *crypted_size = uncrypted_size;
}

void pok_protocols_ceasar_unmarshall	(	void *	crypted_data,
		pok_size_t	crypted_size,
		void *	uncrypted_data,
		size_t *	uncrypted_size
	)

Function that uncrypts data

\brief Unmarshall data, the crypted size has the same size than uncrypted data.

Definition at line 56 of file ceasar.c.

{
   uint8_t* uncrypted;
   uint8_t* crypted;
   size_t   tmp;

   uncrypted   = (uint8_t*) uncrypted_data;
   crypted     = (uint8_t*) crypted_data;

   for (tmp = 0 ; tmp < crypted_size ; tmp++)
   {
         uncrypted[tmp] = (crypted[tmp] - 4) % 255;
   }

   *uncrypted_size = crypted_size;
}