tea.c File Reference

TEA Tiny Encription Algorith functions (implementation). More...

#include "tea.h"
#include <mware/byteorder.h>

Go to the source code of this file.

Functions
void	tea_enc (void *_v, void *_k)
	TEA encryption function.
void	tea_dec (void *_v, void *_k)
	TEA decryption function.

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Detailed Description

TEA Tiny Encription Algorith functions (implementation).

Version:

Id

tea.c 841 2007-10-08 17:35:23Z marco

Author:

Francesco Sacchi <batt@develer.com>

The Tiny Encryption Algorithm (TEA) by David Wheeler and Roger Needham of the Cambridge Computer Laboratory

Placed in the Public Domain by David Wheeler and Roger Needham.

**** ANSI C VERSION ****

Notes:

TEA is a Feistel cipher with XOR and and addition as the non-linear mixing functions.

Takes 64 bits of data in v[0] and v[1]. Returns 64 bits of data in w[0] and w[1]. Takes 128 bits of key in k[0] - k[3].

TEA can be operated in any of the modes of DES. Cipher Block Chaining is, for example, simple to implement.

n is the number of iterations. 32 is ample, 16 is sufficient, as few as eight may be OK. The algorithm achieves good dispersion after six iterations. The iteration count can be made variable if required.

Note this is optimised for 32-bit CPUs with fast shift capabilities. It can very easily be ported to assembly language on most CPUs.

delta is chosen to be the real part of (the golden ratio Sqrt(5/4) - 1/2 ~ 0.618034 multiplied by 2^32).

Definition in file tea.c.

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Function Documentation

void tea_dec	(	void *	_v,
		void *	_k
	)

TEA decryption function.

This function decrypts v with k and returns the decrypted data in v.

Parameters:

	_v	Array of two long values containing the data block.
	_k	Array of four long values containing the key.

Definition at line 124 of file tea.c.

void tea_enc	(	void *	_v,
		void *	_k
	)

TEA encryption function.

This function encrypts v with k and returns the encrypted data in v.

Parameters:

	_v	Array of two long values containing the data block.
	_k	Array of four long values containing the key.

Definition at line 95 of file tea.c.