Ho utilizzato il codice di crittografia / decrittografia dal link .
I vettori di test NIST ( link ) per AES non producono il risultato previsto. Posso sapere quale potrebbe essere la ragione e come farla funzionare secondo i vettori di test NIST?
Per motivi di leggibilità, aggiungerò il seguente codice: #include
#include <openssl/evp.h>
#include <openssl/err.h>
#include <string.h>
int main(int arc, char *argv[])
{
/* Set up the key and iv. Do I need to say to not hard code these in a
* real application? :-)
*/
/* A 256 bit key */
unsigned char ***key** = "0000000000000000000000000000000000000000000000000000000000000000";
/* A 128 bit IV */
unsigned char ***iv** = "00000000000000000000000000000000";
/* Message to be encrypted */
unsigned char *plaintext =
"80000000000000000000000000000000";
/* Buffer for ciphertext. Ensure the buffer is long enough for the
* ciphertext which may be longer than the plaintext, dependant on the
* algorithm and mode
*/
unsigned char ciphertext[128];
/* Buffer for the decrypted text */
unsigned char decryptedtext[128];
int decryptedtext_len, ciphertext_len;
/* Initialise the library */
ERR_load_crypto_strings();
OpenSSL_add_all_algorithms();
OPENSSL_config(NULL);
/* Encrypt the plaintext */
ciphertext_len = encrypt(plaintext, strlen(plaintext), key, iv,
ciphertext);
/* Do something useful with the ciphertext here */
printf("Ciphertext is:\n");
BIO_dump_fp(stdout, ciphertext, ciphertext_len);
/* Decrypt the ciphertext */
decryptedtext_len = decrypt(ciphertext, ciphertext_len, key, iv,
decryptedtext);
/* Add a NULL terminator. We are expecting printable text */
decryptedtext[decryptedtext_len] = '#include <openssl/evp.h>
#include <openssl/err.h>
#include <string.h>
int main(int arc, char *argv[])
{
/* Set up the key and iv. Do I need to say to not hard code these in a
* real application? :-)
*/
/* A 256 bit key */
unsigned char ***key** = "0000000000000000000000000000000000000000000000000000000000000000";
/* A 128 bit IV */
unsigned char ***iv** = "00000000000000000000000000000000";
/* Message to be encrypted */
unsigned char *plaintext =
"80000000000000000000000000000000";
/* Buffer for ciphertext. Ensure the buffer is long enough for the
* ciphertext which may be longer than the plaintext, dependant on the
* algorithm and mode
*/
unsigned char ciphertext[128];
/* Buffer for the decrypted text */
unsigned char decryptedtext[128];
int decryptedtext_len, ciphertext_len;
/* Initialise the library */
ERR_load_crypto_strings();
OpenSSL_add_all_algorithms();
OPENSSL_config(NULL);
/* Encrypt the plaintext */
ciphertext_len = encrypt(plaintext, strlen(plaintext), key, iv,
ciphertext);
/* Do something useful with the ciphertext here */
printf("Ciphertext is:\n");
BIO_dump_fp(stdout, ciphertext, ciphertext_len);
/* Decrypt the ciphertext */
decryptedtext_len = decrypt(ciphertext, ciphertext_len, key, iv,
decryptedtext);
/* Add a NULL terminator. We are expecting printable text */
decryptedtext[decryptedtext_len] = '%pre%';
/* Show the decrypted text */
printf("Decrypted text is:\n");
printf("%s\n", decryptedtext);
/* Clean up */
EVP_cleanup();
ERR_free_strings();
return 0;
}
void handleErrors(void)
{
ERR_print_errors_fp(stderr);
abort();
}
int encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key,
unsigned char *iv, unsigned char *ciphertext)
{
EVP_CIPHER_CTX *ctx;
int len;
int ciphertext_len;
/* Create and initialise the context */
if(!(ctx = EVP_CIPHER_CTX_new())) handleErrors();
/* Initialise the encryption operation. IMPORTANT - ensure you use a key
* and IV size appropriate for your cipher
* In this example we are using 256 bit AES (i.e. a 256 bit key). The
* IV size for *most* modes is the same as the block size. For AES this
* is 128 bits */
if(1 != EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
handleErrors();
/* Provide the message to be encrypted, and obtain the encrypted output.
* EVP_EncryptUpdate can be called multiple times if necessary
*/
if(1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
handleErrors();
ciphertext_len = len;
/* Finalise the encryption. Further ciphertext bytes may be written at
* this stage.
*/
if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len)) handleErrors();
ciphertext_len += len;
/* Clean up */
EVP_CIPHER_CTX_free(ctx);
return ciphertext_len;
}
int decrypt(unsigned char *ciphertext, int ciphertext_len, unsigned char *key,
unsigned char *iv, unsigned char *plaintext)
{
EVP_CIPHER_CTX *ctx;
int len;
int plaintext_len;
/* Create and initialise the context */
if(!(ctx = EVP_CIPHER_CTX_new())) handleErrors();
/* Initialise the decryption operation. IMPORTANT - ensure you use a key
* and IV size appropriate for your cipher
* In this example we are using 256 bit AES (i.e. a 256 bit key). The
* IV size for *most* modes is the same as the block size. For AES this
* is 128 bits */
if(1 != EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
handleErrors();
/* Provide the message to be decrypted, and obtain the plaintext output.
* EVP_DecryptUpdate can be called multiple times if necessary
*/
if(1 != EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len))
handleErrors();
plaintext_len = len;
/* Finalise the decryption. Further plaintext bytes may be written at
* this stage.
*/
if(1 != EVP_DecryptFinal_ex(ctx, plaintext + len, &len)) handleErrors();
plaintext_len += len;
/* Clean up */
EVP_CIPHER_CTX_free(ctx);
return plaintext_len;
}
';
/* Show the decrypted text */
printf("Decrypted text is:\n");
printf("%s\n", decryptedtext);
/* Clean up */
EVP_cleanup();
ERR_free_strings();
return 0;
}
void handleErrors(void)
{
ERR_print_errors_fp(stderr);
abort();
}
int encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key,
unsigned char *iv, unsigned char *ciphertext)
{
EVP_CIPHER_CTX *ctx;
int len;
int ciphertext_len;
/* Create and initialise the context */
if(!(ctx = EVP_CIPHER_CTX_new())) handleErrors();
/* Initialise the encryption operation. IMPORTANT - ensure you use a key
* and IV size appropriate for your cipher
* In this example we are using 256 bit AES (i.e. a 256 bit key). The
* IV size for *most* modes is the same as the block size. For AES this
* is 128 bits */
if(1 != EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
handleErrors();
/* Provide the message to be encrypted, and obtain the encrypted output.
* EVP_EncryptUpdate can be called multiple times if necessary
*/
if(1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
handleErrors();
ciphertext_len = len;
/* Finalise the encryption. Further ciphertext bytes may be written at
* this stage.
*/
if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len)) handleErrors();
ciphertext_len += len;
/* Clean up */
EVP_CIPHER_CTX_free(ctx);
return ciphertext_len;
}
int decrypt(unsigned char *ciphertext, int ciphertext_len, unsigned char *key,
unsigned char *iv, unsigned char *plaintext)
{
EVP_CIPHER_CTX *ctx;
int len;
int plaintext_len;
/* Create and initialise the context */
if(!(ctx = EVP_CIPHER_CTX_new())) handleErrors();
/* Initialise the decryption operation. IMPORTANT - ensure you use a key
* and IV size appropriate for your cipher
* In this example we are using 256 bit AES (i.e. a 256 bit key). The
* IV size for *most* modes is the same as the block size. For AES this
* is 128 bits */
if(1 != EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv))
handleErrors();
/* Provide the message to be decrypted, and obtain the plaintext output.
* EVP_DecryptUpdate can be called multiple times if necessary
*/
if(1 != EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len))
handleErrors();
plaintext_len = len;
/* Finalise the decryption. Further plaintext bytes may be written at
* this stage.
*/
if(1 != EVP_DecryptFinal_ex(ctx, plaintext + len, &len)) handleErrors();
plaintext_len += len;
/* Clean up */
EVP_CIPHER_CTX_free(ctx);
return plaintext_len;
}
L'output che ottengo è:
Il testo cifrato è:
0000 - 0d d2 52 e5 3c 69 ad 57-f2 93 1c 2b 0b 1b 84 a6 ..R.
0010 - 3e c8 b7 ca c5 67 65 82-16 df ac 51 cc ae d7 20 > .... ge .... Q ...
0020 - 6a 2a 39 fd 8f f9 2a b7-e5 6d 27 47 c5 36 ef 65 j * 9 ... * .. m'G.6.e
Il testo decrittografato è:
80000000000000000000000000000000
Ma secondo NIST Test Vector, l'output dovrebbe essere: ddc6bf790c15760d8d9aeb6f9a75fd4e