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mirror of https://github.com/esphome/esphome.git synced 2025-03-19 00:58:13 +00:00
Clyde Stubbs 1215d2ffeb
[xxtea] Extract encryption functions to separate component (#8183)
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
2025-02-05 12:22:40 +13:00

47 lines
916 B
C++

#include "xxtea.h"
namespace esphome {
namespace xxtea {
static const uint32_t DELTA = 0x9e3779b9;
#define MX ((((z >> 5) ^ (y << 2)) + ((y >> 3) ^ (z << 4))) ^ ((sum ^ y) + (k[(p ^ e) & 7] ^ z)))
void encrypt(uint32_t *v, size_t n, const uint32_t *k) {
uint32_t z, y, sum, e;
size_t p;
size_t q = 6 + 52 / n;
sum = 0;
z = v[n - 1];
while (q-- != 0) {
sum += DELTA;
e = (sum >> 2);
for (p = 0; p != n - 1; p++) {
y = v[p + 1];
z = v[p] += MX;
}
y = v[0];
z = v[n - 1] += MX;
}
}
void decrypt(uint32_t *v, size_t n, const uint32_t *k) {
uint32_t z, y, sum, e;
size_t p;
size_t q = 6 + 52 / n;
sum = q * DELTA;
y = v[0];
while (q-- != 0) {
e = (sum >> 2);
for (p = n - 1; p != 0; p--) {
z = v[p - 1];
y = v[p] -= MX;
}
z = v[n - 1];
y = v[0] -= MX;
sum -= DELTA;
}
}
} // namespace xxtea
} // namespace esphome