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/* wipe
*
* by Berke Durak
*
* Arcfour implementation, beta.
*
*/
#include "arcfour.h"
void arcfour_SetupKey (u8 *k, int n, struct arcfour_KeySchedule *ks)
{
int i, j;
u8 kt[256];
for (i = 0, j = 0; i<256; i++) {
ks->s[i] = i;
kt[i] = k[j];
j ++; if (j == n) j = 0;
}
for (i = 0, j = 0; i<256; i++) {
u8 t;
j = 0xff & (j + ks->s[i] + kt[i]);
t = ks->s[i];
ks->s[i] = ks->s[j];
ks->s[j] = t;
}
ks->i = i; ks->j = j;
}
inline u8 arcfour_GetByte (struct arcfour_KeySchedule *ks)
{
int i, j;
u8 x;
i = ks->i; j = ks->j;
i = 0xff & (i+1); j = (j + ks->s[i]) & 0xff;
x = ks->s[i];
ks->s[i] = ks->s[j];
ks->s[j] = x;
ks->i = i; ks->j = j;
return ks->s[(ks->s[i] + ks->s[j]) & 0xff];
}
void arcfour_Fill (struct arcfour_KeySchedule *ks, u8 *b, int n)
{
while (n--) *(b++) = arcfour_GetByte (ks);
}
#ifdef TEST_ARCFOUR
#define TESTKEY "thisisamoddafokkingtest"
#include <stdio.h>
int main (int argc, char **argv)
{
int i;
struct arcfour_KeySchedule ks;
arcfour_SetupKey (TESTKEY, strlen (TESTKEY), &ks);
for (i = 0; i<10240; i++) {
putchar (arcfour_GetByte (&ks));
}
return 0;
}
#undef TESTKEY
#endif
/* vim:set sw=4:set ts=8: */
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