Question

 #include <openssl/rsa.h>
    #include <openssl/pem.h>
    #include <openssl/err.h>
    #include <stdio.h>
    #include <string.h>

    #define KEY_LENGTH  2048
   #define PUB_EXP     3
    #define PRINT_KEYS
    #define WRITE_TO_FILE

int main(void) {
size_t pri_len;            // Length of private key
size_t pub_len;            // Length of public key
char   *pri_key;           // Private key
char   *pub_key;           // Public key
char   msg[KEY_LENGTH/8];  // Message to encrypt
char   *encrypt = NULL;    // Encrypted message
char   *decrypt = NULL;    // Decrypted message
 char   *err;               // Buffer for any error messages

// Generate key pair
printf("Generating RSA (%d bits) keypair...", KEY_LENGTH);
fflush(stdout);
RSA *keypair = RSA_generate_key(KEY_LENGTH, PUB_EXP, NULL, NULL);

// To get the C-string PEM form:
BIO *pri = BIO_new(BIO_s_mem());
BIO *pub = BIO_new(BIO_s_mem());

PEM_write_bio_RSAPrivateKey(pri, keypair, NULL, NULL, 0, NULL, NULL);
PEM_write_bio_RSAPublicKey(pub, keypair);

pri_len = BIO_pending(pri);
pub_len = BIO_pending(pub);

pri_key = malloc(pri_len + 1);
pub_key = malloc(pub_len + 1);

BIO_read(pri, pri_key, pri_len);
BIO_read(pub, pub_key, pub_len);

pri_key[pri_len] = '\0';
pub_key[pub_len] = '\0';

#ifdef PRINT_KEYS
    printf("\n%s\n%s\n", pri_key, pub_key);
#endif
printf("done.\n");

// Get the message to encrypt
printf("Message to encrypt: ");
fgets(msg, KEY_LENGTH-1, stdin);
msg[strlen(msg)-1] = '\0';

// Encrypt the message
encrypt = malloc(RSA_size(keypair));
int encrypt_len;
err = malloc(130);
if((encrypt_len = RSA_public_encrypt(strlen(msg)+1, (unsigned char*)msg, (unsigned char*)encrypt,
                                     keypair, RSA_PKCS1_OAEP_PADDING)) == -1) {
    ERR_load_crypto_strings();
    ERR_error_string(ERR_get_error(), err);
    fprintf(stderr, "Error encrypting message: %s\n", err);
    goto free_stuff;
}

#ifdef WRITE_TO_FILE
// Write the encrypted message to a file
    FILE *out = fopen("out.bin", "w");
    fwrite(encrypt, sizeof(*encrypt),  RSA_size(keypair), out);
    fclose(out);
    printf("Encrypted message written to file.\n");
    free(encrypt);
    encrypt = NULL;

    // Read it back
    printf("Reading back encrypted message and attempting decryption...\n");
    encrypt = malloc(RSA_size(keypair));
    out = fopen("out.bin", "r");
    fread(encrypt, sizeof(*encrypt), RSA_size(keypair), out);
    fclose(out);
#endif

// Decrypt it
decrypt = malloc(encrypt_len);
if(RSA_private_decrypt(encrypt_len, (unsigned char*)encrypt, (unsigned char*)decrypt,
                       keypair, RSA_PKCS1_OAEP_PADDING) == -1) {
    ERR_load_crypto_strings();
    ERR_error_string(ERR_get_error(), err);
    fprintf(stderr, "Error decrypting message: %s\n", err);
    goto free_stuff;
}
printf("Decrypted message: %s\n", decrypt);

free_stuff:
RSA_free(keypair);
BIO_free_all(pub);
BIO_free_all(pri);
free(pri_key);
free(pub_key);
free(encrypt);
free(decrypt);
free(err);

return 0;

}

我试图扩展此代码，允许用户加密任何文本文件并解密文本文件。我试图扩展它包括其他编码，但我甚至不知道从哪里开始。只是想找到我能找到的任何帮助。

扩展加密和解密

0 个答案: