cvs.zerfleddert.de Git - proxmark3-svn/blame_incremental

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Commit	Line	Data
	1	//-----------------------------------------------------------------------------
	2	// This code is licensed to you under the terms of the GNU GPL, version 2 or,
	3	// at your option, any later version. See the LICENSE.txt file for the text of
	4	// the license.
	5	//-----------------------------------------------------------------------------
	6	// Generic TEA crypto code.
	7	// ref: http://143.53.36.235:8080/source.htm#ansi
	8	//-----------------------------------------------------------------------------
	9	#include "tea.h"
	10	#define ROUNDS 32
	11	#define DELTA 0x9E3779B9
	12	#define SUM 0xC6EF3720
	13	#define SWAPENDIAN(x)\
	14	(x = (x >> 8 & 0xff00ff) \| (x & 0xff00ff) << 8, x = x >> 16 \| x << 16)
	15
	16	void tea_encrypt(uint8_t v, uint8_t key) {
	17
	18	uint32_t a=0,b=0,c=0,d=0,y=0,z=0;
	19	uint32_t sum = 0;
	20	uint8_t n = ROUNDS;
	21
	22	//key
	23	a = bytes_to_num(key, 4);
	24	b = bytes_to_num(key+4, 4);
	25	c = bytes_to_num(key+8, 4);
	26	d = bytes_to_num(key+12, 4);
	27
	28	//input
	29	y = bytes_to_num(v, 4);
	30	z = bytes_to_num(v+4, 4);
	31
	32	// SWAPENDIAN(a);
	33	// SWAPENDIAN(b);
	34	// SWAPENDIAN(c);
	35	// SWAPENDIAN(d);
	36	// SWAPENDIAN(y);
	37	// SWAPENDIAN(z);
	38
	39	while ( n-- > 0 ) {
	40	sum += DELTA;
	41	y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
	42	z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
	43	}
	44
	45	// SWAPENDIAN(y);
	46	// SWAPENDIAN(z);
	47
	48	num_to_bytes(y, 4, v);
	49	num_to_bytes(z, 4, v+4);
	50	}
	51
	52	void tea_decrypt(uint8_t v, uint8_t key) {
	53
	54	uint32_t a=0,b=0,c=0,d=0,y=0,z=0;
	55	uint32_t sum = SUM;
	56	uint8_t n = ROUNDS;
	57
	58	//key
	59	a = bytes_to_num(key, 4);
	60	b = bytes_to_num(key+4, 4);
	61	c = bytes_to_num(key+8, 4);
	62	d = bytes_to_num(key+12, 4);
	63
	64	//input
	65	y = bytes_to_num(v, 4);
	66	z = bytes_to_num(v+4, 4);
	67
	68	// SWAPENDIAN(a);
	69	// SWAPENDIAN(b);
	70	// SWAPENDIAN(c);
	71	// SWAPENDIAN(d);
	72	// SWAPENDIAN(y);
	73	// SWAPENDIAN(z);
	74
	75	/* sum = delta<<5, in general sum = delta * n */
	76	while ( n-- > 0 ) {
	77	z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
	78	y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
	79	sum -= DELTA;
	80	}
	81
	82	// SWAPENDIAN(y);
	83	// SWAPENDIAN(z);
	84	num_to_bytes(y, 4, v);
	85	num_to_bytes(z, 4, v+4);
	86	}