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#include "os.h"
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#include <libsec.h>
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void
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setupRC4state(RC4state *key, uchar *start, int n)
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{
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	int t;
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	int index2;
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	uchar *state;
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	uchar *p, *e, *sp, *se;
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	state = key->state;
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	se = &state[256];
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	for(sp = state; sp < se; sp++)
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		*sp = sp - state;
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	key->x = 0;
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	key->y = 0;
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	index2 = 0;
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	e = start + n;
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	p = start;
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	for(sp = state; sp < se; sp++)
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	{
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		t = *sp;
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		index2 = (*p + t + index2) & 255;
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		*sp = state[index2];
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		state[index2] = t;
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		if(++p >= e)
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			p = start;
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	}
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}
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void
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rc4(RC4state *key, uchar *p, int len)
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{
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	int tx, ty;
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	int x, y;
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	uchar *state;
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	uchar *e;
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	x = key->x;
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	y = key->y;
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	state = &key->state[0];
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	for(e = p + len; p < e; p++)
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	{
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		x = (x+1)&255;
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		tx = state[x];
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		y = (y+tx)&255;
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		ty = state[y];
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		state[x] = ty;
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		state[y] = tx;
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		*p ^= state[(tx+ty)&255];
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	}
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	key->x = x;
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	key->y = y;
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}
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void
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rc4skip(RC4state *key, int len)
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{
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	int tx, ty;
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	int x, y;
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	uchar *state;
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	int i;
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	x = key->x;
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	y = key->y;
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	state = &key->state[0];
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	for(i=0; i<len; i++)
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	{
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		x = (x+1)&255;
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		tx = state[x];
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		y = (y+tx)&255;
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		ty = state[y];
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		state[x] = ty;
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		state[y] = tx;
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	}
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	key->x = x;
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	key->y = y;
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}
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void
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rc4back(RC4state *key, int len)
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{
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	int tx, ty;
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	int x, y;
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	uchar *state;
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	int i;
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	x = key->x;
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	y = key->y;
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	state = &key->state[0];
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	for(i=0; i<len; i++)
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	{
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		ty = state[x];
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		tx = state[y];
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		state[y] = ty;
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		state[x] = tx;
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		y = (y-tx)&255;
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		x = (x-1)&255;
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	}
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	key->x = x;
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	key->y = y;
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}