ajout crypto

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>