This commit is contained in:
2025-05-13 12:29:59 +02:00
commit 1bb273e8ac
12 changed files with 304 additions and 0 deletions

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tp1/ex3/fichier1.txt Normal file
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je ne sais pa

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tp1/ex3/hachage Executable file

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tp1/ex3/hachage.c Normal file
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#include <stdio.h>
#include <stdint.h>
#include <string.h>
#define DELTA 0x9e3779b9
void xtea_encrypt(uint32_t v[2], uint32_t const key[4]) {
uint32_t v0 = v[0], v1 = v[1], sum = 0;
for (int i = 0; i < 32; i++) {
v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + key[sum & 3]);
sum += DELTA;
v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + key[(sum >> 11) & 3]);
}
v[0] = v0;
v[1] = v1;
}
void hash_file(const char *filename) {
FILE *f = fopen(filename, "rb");
if (!f) {
perror("Erreur ouverture fichier");
return;
}
uint8_t buffer[24];
uint64_t final_hash[1] = {0};
size_t bytes_read;
while ((bytes_read = fread(buffer, 1, 24, f)) > 0) {
if (bytes_read < 24) {
memset(buffer + bytes_read, 24 - bytes_read, 24 - bytes_read);
}
uint32_t x[2];
memcpy(x, buffer, 8);
uint32_t key[4];
memcpy(key, buffer + 8, 16);
uint32_t x_orig[2] = {x[0], x[1]};
xtea_encrypt(x, key);
x[0] ^= x_orig[0];
x[1] ^= x_orig[1];
final_hash[0] ^= ((uint64_t)x[0] << 32) | x[1];
}
fclose(f);
printf("Empreinte (hachage) : %016llx\n", (unsigned long long)final_hash[0]);
}
int main(int argc, char *argv[]) {
if (argc != 2) {
printf("Usage : %s <fichier>\n", argv[0]);
return 1;
}
hash_file(argv[1]);
return 0;
}