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tp3

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This commit is contained in:
Gael ODDOS- MARCEL
2025-06-10 11:54:50 +02:00
parent fe82635333
commit 7351838abb
14 changed files with 622 additions and 0 deletions
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34
tp3/lib_tea/xtea.c Normal file
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#include "xtea.h"
#include<string.h>
#define TOUR 32
void encrypt_xtea(uint32_t v[2], uint32_t const key[4]) {
unsigned int i;
uint32_t v0=v[0], v1=v[1], sum=0, delta=0x9E3779B9;
for (i=0; i < TOUR; 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 decrypt_xtea(uint32_t v[2], uint32_t const key[4]) {
unsigned int i;
uint32_t v0=v[0], v1=v[1], delta=0x9E3779B9, sum=delta*TOUR;
for (i=0; i < TOUR; i++) {
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + key[(sum>>11) & 3]);
sum -= delta;
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + key[sum & 3]);
}
v[0]=v0; v[1]=v1;
}
uint64_t hash_block_xtea(char b[24])
{
uint32_t v[2];
uint32_t k[4];
memcpy(v,b,2*sizeof(uint32_t));
memcpy(k,b+2*sizeof(uint32_t),4*sizeof(uint32_t));
encrypt_xtea(v,k);
return ((uint64_t)v[0])<<32 | v[1];
}