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#include <stdint.h>
#include "scramble.h"
void scramble(uint8_t *in, uint8_t *out, const int size)
{
/* table extracted from bootrom */
static const uint8_t key[] = {
0x7C, 0x4E, 0x03, 0x04,
0x55, 0x05, 0x09, 0x07,
0x2D, 0x2C, 0x7B, 0x38,
0x17, 0x0D, 0x17, 0x11
};
int i, i3, x, val, idx;
uint8_t key1[0x100];
uint8_t key2[0x100];
for (i=0; i<0x100; i++) {
key1[i] = i;
key2[i] = key[i&0xf];
}
i3 = 0;
for (i=0; i<0x100; i++) {
x = key1[i];
i3 = key1[i] + i3;
i3 += key2[i];
i3 &= 0xff;
key1[i] = key1[i3];
key1[i3] = x;
}
idx = 0;
for (i=0; i<size; i++) {
x = key1[(i+1) & 0xff];
val = x;
idx = (x + idx) & 0xff;
key1[(i+1) & 0xff] = key1[idx];
key1[idx] = (x & 0xff);
val = (key1[(i+1)&0xff] + x) & 0xff;
val = key1[val];
out[i] = val ^ in[i];
}
}
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