add .c and exemple_collision.c (cc6bb2ce) · Commits · Antonin Hardel / TP Introduction à la sécurité L2

src/bst.c

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		struct node_t {
		unsigned long int key;
		void* val;
		struct node_t* left;
		struct node_t* right;
		};

		typedef struct bst_t {
		// Use this to compute a key from a val
		// It is not really a hash function, the key must be unique
		unsigned long int (h)(void);

		unsigned long int size;
		struct node_t* tree;
		} bst_t;

		bst_t bst_empty(void){
		}

		int bst_is_empty(bst_t t){
		}

		bst_t bst_add(bst_t t, void* x){
		}

		void bst_destroy(bst_t t, void (free_void)(void)){
		}

		int bst_in(bst_t t, void* x){
		}

		unsigned long int bst_size(bst_t t){
		}

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		#include <stddef.h>
		#include "list.h"

		#define ARRAY_CAPACITY 1 << 16

		struct hash_tbl {
		size_t (h)(void);
		int (eq)(void, void*);
		void (free)(void);
		unsigned long int size;
		size_t capacity; // array length
		list_t* array;
		};

		typedef struct hash_tbl* hash_tbl;

		hash_tbl htbl_empty(size_t (h)(void),
		int (eq)(void, void*),
		void (free)(void)){
		}

		int htbl_add(hash_tbl htbl, void* x){
		}

		int htbl_in(hash_tbl htbl, void* x){
		}

		void htbl_destroy(hash_tbl htbl){
		}

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		struct cell_t {
		void* val;
		unsigned long int id;
		struct cell_t* next;
		};

		typedef struct cell_t* list_t;

		list_t list_empty(){
		}

		int list_is_empty(list_t l){
		}

		list_t list_push(list_t l, void* x){
		}

		list_t list_tail(list_t l){
		}

		void* list_pop(list_t* l){
		}

		void* list_top(list_t l){
		}

		void list_destroy(list_t l, void (free)(void)){
		}

		// return the found element or NULL
		void* list_in(list_t l, void* x, int (eq)(void, void*)){
		}

		unsigned long int list_len(list_t l){
		}

+1 −1

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		@@ -16,7 +16,7 @@ list_t list_tail(list_t);
		void* list_pop(list_t*);
		void* list_top(list_t);
		void list_destroy(list_t, void (free)(void));
		int list_in(list_t, void, int (eq)(void, void));
		void* list_in(list_t, void, int (eq)(void, void));
		unsigned long int list_len(list_t);

		#endif

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		#include <stdlib.h>
		#include <stdio.h>
		#include <time.h>
		#include <openssl/md5.h>
		#include "list.h"

		typedef struct pair_t {
		char x[8];
		unsigned char h;
		}* pair_t;

		int eq_pair(void* a, void* b){
		return ((pair_t)a)->h == ((pair_t)b)->h;
		}

		/* char x[8] */
		unsigned char md5_first_byte(const char* x){
		unsigned char digest[MD5_DIGEST_LENGTH];

		MD5((const unsigned char*)x, 8, digest);
		return digest[0]; // we keep only the first byte
		}

		int main(){
		pair_t p, q;
		list_t l;
		unsigned int i = 0;

		srand(time(NULL));

		l = list_empty();

		for(;;){
		p = (pair_t)malloc(sizeof(struct pair_t));
		for(int i = 0; i < 7; i++)
		p->x[i] = rand() % (126-32-1) + 32;
		p->x[7] = 0;
		p->h = md5_first_byte(p->x);

		if((q = (pair_t)list_in(l, p, eq_pair)) != NULL){
		printf("After %d iterations, a collision happened !\n", i);
		printf("%s and %s have the same MD5 first byte.\n", p->x, q->x);

		return 0;
		} else {
		l = list_push(l, p);
		}
		}
		}