ajout crypto

crypto/TP1/Ex1/file.txt

@@ -0,0 +1,16 @@
+Demain, dès l'aube, à l'heure où blanchit la campagne,
+Je partirai. Vois-tu, je sais que tu m'attends.
+J'irai par la forêt, j'irai par la montagne.
+Je ne puis demeurer loin de toi plus longtemps.
+
+Je marcherai les yeux fixés sur mes pensées,
+Sans rien voir au dehors, sans entendre aucun bruit,
+Seul, inconnu, le dos courbé, les mains croisées,
+Triste, et le jour pour moi sera comme la nuit.
+
+Je ne regarderai ni l'or du soir qui tombe,
+Ni les voiles au loin descendant vers Harfleur,
+Et quand j'arriverai, je mettrai sur ta tombe
+Un bouquet de houx vert et de bruyère en fleur.
+
+— Victor Hugo, Les Contemplations, 3 septembre 1847

crypto/TP1/Ex1/lfsr.c

@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#define MASK_BIT_7      0x80
+#define MASK_BIT_6      0x40
+#define MASK_BIT_5      0x20
+#define MASK_BIT_4      0x10
+#define MASK_BIT_3      0x08
+#define MASK_BIT_2      0x04
+#define MASK_BIT_1      0x02
+#define MASK_BIT_0      0x01
+
+
+unsigned char next(unsigned char lfsr)
+{
+	unsigned char new_bit = __builtin_parity(lfsr & (MASK_BIT_7 | MASK_BIT_6 | MASK_BIT_5 | MASK_BIT_4 | MASK_BIT_3 | MASK_BIT_1));
+    return (lfsr << 1) | new_bit;
+}
+
+int main(int argc, char *argv[])
+{
+	int fd_in,fd_out;
+	unsigned char w,buf;;
+
+
+	assert(argc >= 4);
+	fd_in = open(argv[1],O_RDONLY);
+	fd_out = open(argv[2],O_WRONLY|O_TRUNC|O_CREAT,0600);
+	w = (unsigned char)strtol(argv[3],NULL,0);
+
+	while(1){
+		ssize_t nb = read(fd_in,&buf,1);
+		if (nb <=0)
+			break;
+		buf ^= w;
+		write(fd_out,&buf,1);
+		w=next(w);
+	}
+	return 0;
+}

crypto/TP1/Ex2/key1.k

@@ -0,0 +1 @@
+÷Nà{q2‘*:¬¨œÇmfU#©`í±Å?&Q3

crypto/TP1/Ex2/xtea.c

@@ -0,0 +1,66 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#define DELTA 0x9E3779B9
+#define ROUNDS 32
+
+void decrypt(uint32_t v[2], uint32_t const key[4]) {
+    uint32_t v0 = v[0], v1 = v[1], sum = DELTA * ROUNDS;
+    for (int i = 0; i < ROUNDS; 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;
+}
+
+void 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 < ROUNDS; 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 process_file(const char *mode, const char *keyfile, const char *inputfile, const char *outputfile) {
+    uint32_t key[4];
+    uint32_t block[2];
+    int fd_key = open(keyfile, O_RDONLY);
+    int fd_in = open(inputfile, O_RDONLY);
+    int fd_out = open(outputfile, O_WRONLY | O_CREAT | O_TRUNC, 0600);
+    
+    if (fd_key < 0 || fd_in < 0 || fd_out < 0) {
+        perror("Error opening file");
+        exit(1);
+    }
+    read(fd_key, key, sizeof(key));
+    close(fd_key);
+    
+    while (read(fd_in, block, sizeof(block)) == sizeof(block)) {
+        if (strcmp(mode, "-d") == 0) {
+            decrypt(block, key);
+        } else {
+            encrypt(block, key);
+        }
+        write(fd_out, block, sizeof(block));
+    }
+    close(fd_in);
+    close(fd_out);
+}
+
+int main(int argc, char *argv[]) {
+    if (argc != 5) {
+        fprintf(stderr, "Usage: %s -e|-d filekey file1 file2\n", argv[0]);
+        return 1;
+    }
+    process_file(argv[1], argv[2], argv[3], argv[4]);
+    return 0;
+}

crypto/TP1/Ex3/Xtea_hash.c

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#define DELTA 0x9E3779B9
+#define ROUNDS 32
+#define BLOCK_SIZE 24
+
+void 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 < ROUNDS; 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 xtea_hash(const char *filename, uint64_t *hash) {
+    int fd = open(filename, O_RDONLY);
+    if (fd < 0) {
+        perror("Error opening file");
+        exit(1);
+    }
+    
+    uint64_t current_hash = 0;
+    uint8_t buffer[BLOCK_SIZE];
+    ssize_t bytes_read;
+    
+    while ((bytes_read = read(fd, buffer, BLOCK_SIZE)) > 0) {
+        if (bytes_read < BLOCK_SIZE) {
+            memset(buffer + bytes_read, 0, BLOCK_SIZE - bytes_read);
+            buffer[BLOCK_SIZE - 1] = BLOCK_SIZE - bytes_read;
+        }
+        
+        uint32_t x[2];
+        uint32_t k[4];
+        memcpy(x, buffer, 8);
+        memcpy(k, buffer + 8, 16);
+        
+        encrypt(x, k);
+        uint64_t hashed_block = ((uint64_t)x[0] << 32) | x[1];
+        current_hash ^= hashed_block;
+    }
+    
+    close(fd);
+    *hash = current_hash;
+}
+
+int main(int argc, char *argv[]) {
+    if (argc != 2) {
+        fprintf(stderr, "Usage: %s <file>\n", argv[0]);
+        return 1;
+    }
+    
+    uint64_t hash;
+    xtea_hash(argv[1], &hash);
+    printf("Hash: %016lx\n", hash);
+    return 0;
+}

crypto/TP2/forcebrute/16bits-encrypted.dat

@@ -0,0 +1 @@
+&&&ÅS£PšØ¦<C398>š&쓦Qc&RëéR&Rë£&<26>Ú¡£&éP£&î¦é<C2A6>£<EFBFBD>¶&&&ÅS£PšØ¦<C398>š&P¦îîc&QÚRë&Rë£ÚP&‘Ú“Ù£Pc&¡P¦cc£<63>¶&&&ÅS£PšØ¦<C398>š&쓦Qc&RëéR&Rë£&QéP&Úc&¦S£P¶&&&ÅS£PšØ¦<C398>š&쓦Qc&Rë£&Ù¦¦<C2A6>&Ù)šc&î¦cR¶&&&ÅS£PšØ¦<C398>š&쓦Qc&Rë£&‘ÚÙëR&Qéc&‘Ú«£<C2AB>¶&&&¼ë£&f¦¦P&cRéš&f¦¦Pl&Rë£&PÚ¡ë&Ù£R&PÚ¡ë¶&&¼ëéR[c&ë¦Q&ÚR&Ù¦£c¶&&ÅS£PšØ¦<C398>š&쓦Qc¶¶

crypto/TP2/main.c

@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include "spn.h"
+
+int main() {
+    unsigned char s[16] = {14, 3, 2, 10, 12, 11, 15, 9, 0, 4, 7, 13, 1, 8, 6, 5};
+    unsigned char perm[8] = {5, 2, 0, 4, 6, 1, 7, 3};
+    unsigned short key = 0xABCD; // Exemple de clé
+
+    unsigned char plaintext = 0x3C; // Exemple de bloc clair (0011 1100)
+    printf("Texte clair : 0x%02X\n", plaintext);
+
+    unsigned char ciphertext = encrypt(plaintext, key, perm, s);
+    printf("Texte chiffré : 0x%02X\n", ciphertext);
+
+    unsigned char decrypted = decrypt(ciphertext, key, perm, s);
+    printf("Texte déchiffré : 0x%02X\n", decrypted);
+
+    return 0;
+}

crypto/TP2/spn.c

@@ -0,0 +1,112 @@
+#include "spn.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+// Applique la permutation définie par perm à l'octet w
+unsigned char do_perm(unsigned char w, unsigned char perm[8]) {
+    unsigned char res = 0;
+    for (int i = 0; i < 8; i++) {
+        if (w & (1 << i)) {
+            res |= (1 << perm[i]);
+        }
+    }
+    return res;
+}
+
+// Applique la substitution définie par subst sur chaque moitié de w
+unsigned char do_subst(unsigned char w, unsigned char subst[16]) {
+    unsigned char left = (w >> 4) & 0x0F; // 4 bits de poids fort
+    unsigned char right = w & 0x0F;       // 4 bits de poids faible
+    return (subst[left] << 4) | subst[right];
+}
+
+// Chiffre un bloc de 8 bits avec une clé de 16 bits
+unsigned char encrypt(
+    unsigned char w,
+    unsigned short key,
+    unsigned char perm[8],
+    unsigned char subst[16]
+) {
+    unsigned char subkey1 = (key >> 8) & 0xFF;
+    unsigned char subkey2 = key & 0xFF;
+
+    // Tour 1 : XOR avec la clé, substitution, permutation
+    w ^= subkey1;
+    w = do_subst(w, subst);
+    w = do_perm(w, perm);
+
+    // Tour 2 : XOR avec la clé, substitution, XOR avec la sous-clé finale
+    w ^= subkey2;
+    w = do_subst(w, subst);
+    w ^= subkey1;
+
+    return w;
+}
+
+// Déchiffre un bloc de 8 bits avec une clé de 16 bits
+unsigned char decrypt(
+    unsigned char w,
+    unsigned short key,
+    unsigned char perm[8],
+    unsigned char subst[16]
+) {
+    unsigned char subkey1 = (key >> 8) & 0xFF;
+    unsigned char subkey2 = key & 0xFF;
+
+    // Table de substitution inverse
+    unsigned char inv_subst[16];
+    for (int i = 0; i < 16; i++) {
+        inv_subst[subst[i]] = i;
+    }
+
+    // Tour inverse 2 : XOR avec la clé, substitution inverse, XOR avec la sous-clé
+    w ^= subkey1;
+    w = do_subst(w, inv_subst);
+    w ^= subkey2;
+
+    // Tour inverse 1 : permutation inverse, substitution inverse, XOR avec la clé
+    unsigned char inv_perm[8];
+    for (int i = 0; i < 8; i++) {
+        inv_perm[perm[i]] = i;
+    }
+    w = do_perm(w, inv_perm);
+    w = do_subst(w, inv_subst);
+    w ^= subkey1;
+
+    return w;
+}
+
+void read_key(const char *filename, unsigned short *key) {
+    FILE *file = fopen(filename, "r");
+    if (!file) {
+        perror("Erreur ouverture fichier clé");
+        exit(EXIT_FAILURE);
+    }
+    fscanf(file, "%hx", key); // Lire un entier hexadécimal (16 bits)
+    fclose(file);
+}
+
+void read_subst(const char *filename, unsigned char subst[16]) {
+    FILE *file = fopen(filename, "r");
+    if (!file) {
+        perror("Erreur ouverture fichier substitution");
+        exit(EXIT_FAILURE);
+    }
+    for (int i = 0; i < 16; i++) {
+        fscanf(file, "%hhu", &subst[i]); // Lire un entier 8 bits
+    }
+    fclose(file);
+}
+
+void read_perm(const char *filename, unsigned char perm[8]) {
+    FILE *file = fopen(filename, "r");
+    if (!file) {
+        perror("Erreur ouverture fichier permutation");
+        exit(EXIT_FAILURE);
+    }
+    for (int i = 0; i < 8; i++) {
+        fscanf(file, "%hhu", &perm[i]); // Lire un entier 8 bits
+    }
+    fclose(file);
+}

crypto/TP2/spn.h

@@ -0,0 +1,17 @@
+#ifndef _SPN_H
+#define _SPN_H
+
+#include <stdint.h>
+#include <stdio.h>
+
+unsigned char do_perm(unsigned char w, unsigned char perm[8]);
+unsigned char do_subst(unsigned char w, unsigned char subst[16]);
+unsigned char encrypt(unsigned char w, unsigned short key, unsigned char perm[8], unsigned char subst[16]);
+unsigned char decrypt(unsigned char w, unsigned short key, unsigned char perm[8], unsigned char subst[16]);
+
+// Ajout des déclarations des fonctions de lecture
+void read_key(const char *filename, unsigned short *key);
+void read_subst(const char *filename, unsigned char subst[16]);
+void read_perm(const char *filename, unsigned char perm[8]);
+
+#endif

crypto/TP2/spn_decrypt_file.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "spn.h"
+
+void decrypt_file(const char *input_filename, const char *output_filename, unsigned short key, unsigned char perm[8], unsigned char subst[16]) {
+    FILE *in = fopen(input_filename, "rb");
+    FILE *out = fopen(output_filename, "wb");
+    if (!in || !out) {
+        perror("Erreur ouverture fichier");
+        exit(EXIT_FAILURE);
+    }
+
+    unsigned char byte;
+    while (fread(&byte, 1, 1, in) == 1) {
+        unsigned char decrypted = decrypt(byte, key, perm, subst);
+        fwrite(&decrypted, 1, 1, out);
+    }
+
+    fclose(in);
+    fclose(out);
+}
+
+int main(int argc, char *argv[]) {
+    if (argc != 6) {
+        printf("Usage: %s clé.txt subst.txt perm.txt fichier_chiffre fichier_déchiffré\n", argv[0]);
+        return EXIT_FAILURE;
+    }
+
+    unsigned short key;
+    unsigned char subst[16];
+    unsigned char perm[8];
+
+    read_key(argv[1], &key);
+    read_subst(argv[2], subst);
+    read_perm(argv[3], perm);
+
+    decrypt_file(argv[4], argv[5], key, perm, subst);
+
+    printf("Déchiffrement terminé : %s → %s\n", argv[4], argv[5]);
+    return EXIT_SUCCESS;
+}

crypto/TP2/spn_encrypt_file.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "spn.h"
+
+void encrypt_file(const char *input_filename, const char *output_filename, unsigned short key, unsigned char perm[8], unsigned char subst[16]) {
+    FILE *in = fopen(input_filename, "rb");
+    FILE *out = fopen(output_filename, "wb");
+    if (!in || !out) {
+        perror("Erreur ouverture fichier");
+        exit(EXIT_FAILURE);
+    }
+
+    unsigned char byte;
+    while (fread(&byte, 1, 1, in) == 1) {
+        unsigned char encrypted = encrypt(byte, key, perm, subst);
+        fwrite(&encrypted, 1, 1, out);
+    }
+
+    fclose(in);
+    fclose(out);
+}
+
+int main(int argc, char *argv[]) {
+    if (argc != 6) {
+        printf("Usage: %s clé.txt subst.txt perm.txt fichier_clair fichier_chiffre\n", argv[0]);
+        return EXIT_FAILURE;
+    }
+
+    unsigned short key;
+    unsigned char subst[16];
+    unsigned char perm[8];
+
+    read_key(argv[1], &key);
+    read_subst(argv[2], subst);
+    read_perm(argv[3], perm);
+
+    encrypt_file(argv[4], argv[5], key, perm, subst);
+
+    printf("Chiffrement terminé : %s → %s\n", argv[4], argv[5]);
+    return EXIT_SUCCESS;
+}

crypto/TP2/tests_ex2/key

@@ -0,0 +1 @@
+<EFBFBD>