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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/evp.h>
#include <openssl/rand.h>
#include <openssl/aes.h>
#define MAX_PASSWORD_LENGTH 128
#define AES_KEY_SIZE 256 / 8
struct Password {
char website[128];
char username[128];
char password[MAX_PASSWORD_LENGTH];
char notes[256];
};
void generate_password(char *password, int length) {
// Generate a random password of the specified length
// using a combination of upper and lowercase letters, digits, and special characters
char charset[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()_+-=[]{}\\|;:'\",.<>/?";
int charset_size = strlen(charset);
for (int i = 0; i < length; i++) {
int index = rand() % charset_size;
password[i] = charset[index];
}
password[length] = '\0';
}
void encrypt_password(struct Password *password, unsigned char *key) {
AES_KEY aes_key;
unsigned char iv[AES_BLOCK_SIZE];
unsigned char encrypted_password[AES_BLOCK_SIZE];
// Generate a random initialization vector
RAND_bytes(iv, AES_BLOCK_SIZE);
// Initialize the encryption key
EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv);
// Encrypt the password using AES-256 encryption
int outlen, tmplen;
EVP_EncryptUpdate(ctx, encrypted_password, &outlen, (unsigned char*)password->password, AES_BLOCK_SIZE);
EVP_EncryptFinal_ex(ctx, encrypted_password + outlen, &tmplen);
// Copy the encrypted password and IV back into the password struct
memcpy(password->password, encrypted_password, AES_BLOCK_SIZE);
memcpy(password->notes, iv, AES_BLOCK_SIZE);
// Clean up
EVP_CIPHER_CTX_free(ctx);
}
void decrypt_password(struct Password *password, unsigned char *key) {
EVP_CIPHER_CTX *ctx;
unsigned char iv[AES_BLOCK_SIZE];
unsigned char decrypted_password[AES_BLOCK_SIZE];
// Read the initialization vector from the password struct
memcpy(iv, password->notes, AES_BLOCK_SIZE);
// Initialize the decryption context
ctx = EVP_CIPHER_CTX_new();
EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv);
// Decrypt the password using AES-256 decryption
int outlen, tmplen;
EVP_DecryptUpdate(ctx, decrypted_password, &outlen, (unsigned char*)password->password, AES_BLOCK_SIZE);
EVP_DecryptFinal_ex(ctx, decrypted_password + outlen, &tmplen);
// Copy the decrypted password back into the password struct
memcpy(password->password, decrypted_password, MAX_PASSWORD_LENGTH);
// Clean up
EVP_CIPHER_CTX_free(ctx);
}
void save_password(struct Password *password, char *filename, unsigned char *key) {
// Save the password information to a file in an encrypted format using AES-256 encryption
FILE *fp = fopen(filename, "wb");
if (fp == NULL) {
printf("Error: could not open file %s for writing.\n", filename);
return;
}
// Encrypt the password information
encrypt_password(password, key);
// Write the encrypted password information to the file
fwrite(password, sizeof(struct Password), 1, fp);
fclose(fp);
}
void load_password(struct Password *password, char *filename, unsigned char *key) {
// Load the password information from a file and decrypt it using AES-256 decryption
// Open the file for reading
FILE *file = fopen(filename, "rb");
if (file == NULL) {
printf("Error: Could not open file %s\n", filename);
return;
}
// Read the encrypted password information from the file
unsigned char iv[AES_BLOCK_SIZE];
fread(iv, 1, AES_BLOCK_SIZE, file);
unsigned char encrypted[sizeof(struct Password)];
fread(encrypted, 1, sizeof(struct Password), file);
// Decrypt the password information
AES_KEY aes_key;
EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new();
EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv);
int outlen, finallen;
EVP_DecryptUpdate(ctx, (unsigned char*)password, &outlen, encrypted, sizeof(struct Password));
EVP_DecryptFinal_ex(ctx, ((unsigned char*)password) + outlen, &finallen);
EVP_CIPHER_CTX_free(ctx);
// Close the file
fclose(file);
}
int main() {
int choice;
char filename[256];
struct Password password;
unsigned char key[AES_BLOCK_SIZE];
// Get the encryption key from the user
printf("Enter the encryption key: ");
char key_str[AES_BLOCK_SIZE];
printf("Enter the encryption key: ");
fgets(key_str, AES_BLOCK_SIZE, stdin);
for (int i = 0; i < AES_BLOCK_SIZE; i++) {
key[i] = (unsigned char) key_str[i];
}
// Loop until the user chooses to exit the program
do {
// Display the menu of options to the user
printf("\n1. Generate new password\n");
printf("2. Save password information to file\n");
printf("3. Load password information from file\n");
printf("4. Exit program\n\n");
printf("Enter your choice: ");
scanf("%d", &choice);
switch (choice) {
case 1:
// Generate a new password and display it to the user
generate_password(password.password, MAX_PASSWORD_LENGTH);
printf("New password: %s\n", password.password);
break;
case 2:
// Get the filename from the user and save the password information to a file
printf("Enter the filename to save to: ");
scanf("%s", filename);
save_password(&password, filename, key);
printf("Password information saved to %s\n", filename);
break;
case 3:
// Get the filename from the user and load the password information from a file
printf("Enter the filename to load from:");
scanf("%s", filename);
load_password(&password, filename, key);
printf("Password information loaded from %s\n", filename);
// Display the password information to the user
printf("Website: %s\n", password.website);
printf("Username: %s\n", password.username);
printf("Password: %s\n", password.password);
printf("Notes: %s\n", password.notes);
break;
case 4:
// Exit the program
printf("Exiting program...\n");
break;
default:
// Invalid choice
printf("Invalid choice. Please enter a number between 1 and 4.\n");
break;
}
} while (choice != 4);
return 0;
}
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