Grandville.net | OpenSSL / AES-CBC-EVP

OpenSSL/AES-CBC-EVP

OpenSSL.AES-CBC-EVP History

Hide minor edits - Show changes to output

January 16, 2009, at 08:34 AM by 82.66.132.163 -

Changed lines 1-2 from:

(:keywords openssl, aes, cipher:)
(:description ~~II► Arnaud Grandville Consulting, Lille, conseils et intégration de solutions informatiques~~ :)

to:

(:keywords openssl, aes, cipher,AES_cbc_encrypt,EVP_Encrypt :)
(:description These samples show how to use AES_cbc_encrypt and EVP_Encrypt API :)

Restore

October 09, 2007, at 10:52 PM by Arnaud Grandville -

Changed lines 2-3 from:

(:description &#~~xbb;»&#xbb~~; Arnaud Grandville Consulting, Lille, conseils et intégration de solutions informatiques :)

to:

(:description II► Arnaud Grandville Consulting, Lille, conseils et intégration de solutions informatiques :)

Restore

October 09, 2007, at 10:48 PM by Arnaud Grandville -

Added lines 1-3:

(:keywords openssl, aes, cipher:)
(:description »»» Arnaud Grandville Consulting, Lille, conseils et intégration de solutions informatiques :)

Restore

September 03, 2007, at 01:03 PM by Arnaud Grandville -

Changed lines 29-30 from:

to:

#define BIG_TEST_SIZE 10240

Changed lines 59-60 from:

~~unsigned matches;~~

to:

Restore

September 03, 2007, at 01:01 PM by Arnaud Grandville -

Changed line 3 from:

Deux ~~méthodes~~ de chiffrement AES:\\

to:

Deux API de chiffrement AES:\\

Changed lines 5-6 from:

- EVP_Encrypt

to:

- EVP_Encrypt\\

Cette dernière API intégre deux fonctions intéressantes :\\
- Fournir la taille de la chaine d'origine surtout utile lorsque le cryptage utilise un padding\\
- Valide que la clef de décryptage est celle attendue.\\

Changed lines 159-160 from:

hexdump(stdout, "checktext", outbuf2, outlen2~~+tmplen~~);

to:

outlen2+=tmplen;
hexdump(stdout, "checktext", outbuf2, outlen2);
EVP_CIPHER_CTX_cleanup(&x);

Restore

September 03, 2007, at 12:28 AM by Arnaud Grandville -

Added lines 1-154:

'+Chiffrement AES+'

Deux méthodes de chiffrement AES:\\
- AES_cbc_encrypt\\
- EVP_Encrypt

\\
\\

'+Méthode avec AES_cbc_encrypt+'

(:source lang=C :)
#include <openssl/aes.h>
#include <openssl/evp.h>
#include <stdio.h>
#include <openssl/sha.h>
#include <openssl/rand.h>
#include <Windows.h>
#include <assert.h>
#include <openssl/err.h>

static void hexdump(FILE *f,const char *title,const unsigned char *s,int l)
{
int n=0;

fprintf(f,"%s",title);
for( ; n < l ; ++n)
{
if((n%16) == 0)
fprintf(f,"\n%04x",n);
fprintf(f," %02x",s[n]);
}
fprintf(f,"\n");
}

int main(int argc, char* argv[])
{
const KEYSIZE=AES_BLOCK_SIZE;
char rkey[KEYSIZE+1];
char rkey2[KEYSIZE+1];
AES_KEY key;
AES_KEY key2;
char plaintext[BIG_TEST_SIZE];
char ciphertext[BIG_TEST_SIZE];
char checktext[BIG_TEST_SIZE];
char iv[AES_BLOCK_SIZE*4];
char saved_iv[AES_BLOCK_SIZE*4];
int err = 0;
int n;
unsigned matches;

RAND_pseudo_bytes((unsigned char*)rkey, sizeof rkey);
strcpy(iv,"0123456789012345");

memcpy(saved_iv, iv, sizeof saved_iv);

strcpy((char*)plaintext,"string to make the random number generator think it has entropy");

// Straight encrypt

AES_set_encrypt_key((unsigned char*)rkey, 8*KEYSIZE, &key);
hexdump(stdout, "plaintext", (unsigned char*)plaintext, strlen(plaintext));

AES_cbc_encrypt((unsigned char*)plaintext, (unsigned char*)ciphertext, strlen(plaintext), &key, (unsigned char*)iv,AES_ENCRYPT);
hexdump(stdout, "ciphertext", (unsigned char*)ciphertext, strlen(plaintext));

// Straight decrypt

AES_set_decrypt_key((unsigned char*)rkey, 8*KEYSIZE, &key);
memcpy(iv, saved_iv, sizeof iv);
AES_cbc_encrypt((unsigned char*)ciphertext, (unsigned char*)checktext, strlen(plaintext), &key, (unsigned char*)iv,AES_DECRYPT);
hexdump(stdout, "checktext", (unsigned char*)checktext, strlen(plaintext));

return 0;
}
(:sourcend:)

'+Méthode avec EVP+'

(:source lang=C :)
#include <openssl/aes.h>
#include <openssl/evp.h>
#include <stdio.h>
#include <openssl/sha.h>
#include <openssl/rand.h>
#include <Windows.h>
#include <assert.h>
#include <openssl/err.h>

static void hexdump(FILE *f,const char *title,const unsigned char *s,int l)
{
int n=0;

fprintf(f,"%s",title);
for( ; n < l ; ++n)
{
if((n%16) == 0)
fprintf(f,"\n%04x",n);
fprintf(f," %02x",s[n]);
}
fprintf(f,"\n");
}

int main(int argc, char* argv[])
{
unsigned char outbuf2[1024];
unsigned char outbuf[1024];
int outlen, outlen2, tmplen;
unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
unsigned char iv[] = {1,2,3,4,5,6,7,8};
char intext[] = "string to make the random number generator think it has entropy";

hexdump(stdout, "plaintext", (unsigned char*)intext, strlen(intext));

// Straight encrypt

EVP_CIPHER_CTX x;
EVP_CIPHER_CTX_init(&x);
if(!EVP_EncryptInit_ex(&x, EVP_aes_128_cbc(), NULL, key, iv))
printf("\n ERROR!! \n");
if(!EVP_EncryptUpdate(&x, outbuf, &outlen,(const unsigned char*) intext, strlen(intext)))
printf("\n ERROR!! \n");
if(!EVP_EncryptFinal_ex(&x,outbuf+outlen,&tmplen))
printf("\n ERROR!! \n");

outlen+=tmplen;
hexdump(stdout, "ciphertext", outbuf, outlen);

EVP_CIPHER_CTX_cleanup(&x);

// Straight decrypt

tmplen=0;
outlen2=0;
EVP_CIPHER_CTX_init(&x);
EVP_DecryptInit_ex(&x, EVP_aes_128_cbc(), NULL, key, iv);
if(!EVP_DecryptUpdate(&x, outbuf2, &outlen2,(const unsigned char*) outbuf, outlen))
printf("\n ERROR!! \n");
if(!EVP_DecryptFinal_ex(&x, outbuf2 + outlen2, &tmplen)){
unsigned long error, reason,err;
char buf[128];
error = ERR_peek_error();
reason = ERR_GET_REASON(error);
//EVP_R_BAD_DECRYPT
ERR_error_string_n(reason,buf,128);
printf("%s",buf);
}

hexdump(stdout, "checktext", outbuf2, outlen2+tmplen);
}
(:sourcend:)

Restore