the different encrypt result of ipp and openssl

[Chen_Chen]

recently, i used ipp and openssl libraries to encrypt the same plain text ,but i get two different results,

the encrypt algorithm is aes and the encrypt mode is cfb, the codes are as follows:

#include

#include

#include

#include

#include

#include

#include "ipp.h"

#include "ippcore.h"

#define keylen 32

int main()

{

int size=64;

ippInit();

Ipp8u iv[32];// change unsigned char --->Ipp8u;

Ipp8u key[32];

int num_threads;

int i;

int count=0;

int c_len; //ciphertext len;

int len; //plaintext len;

double costtime;

int j;

int ctxsize;

double timesum;

for (i=0; i<32; i++) /*generate the init-vector*/

{

iv=rand()%10;

//printf("%d ",iv);

}

for (i=0;i<32;i++) /*generate the key*/

{

key=rand()%10;

//printf("%d ",key);

}

len=size;

c_len=len;

unsigned char *plaintext=(Ipp8u *)malloc(len);;//change unsigned char-->Ipp8u;

unsigned char *ciphertext=(Ipp8u *)malloc(c_len);

memset(ciphertext,0,c_len);

for(i=0;i

{

plaintext=rand()%10+'0';

}

printf("\\n the plaintext is %s\\n",plaintext);

//the encrypto process;

/*the part next is the encrypt process operated by Intel@IPP cryptography library*/

//--------------------encrypt with ipp----------------------------

ippsRijndael256GetSize(&ctxsize);

IppsRijndael256Spec* pCtx = (IppsRijndael256Spec*)(new Ipp8u [ctxsize]);

ippsRijndael256Init(key,IppsRijndaelKey256,pCtx);//??????

ippsRijndael256EncryptCFB(plaintext,ciphertext,len,32,pCtx,iv,IppsCPPaddingNONE);

delete (Ipp8u*)pCtx;

printf("the ipp ciphertext is %s\\n",ciphertext);

//--------------------encrypt with openssl---------------------------

EVP_CIPHER_CTX enc_ctx;

EVP_CIPHER *cipher=(EVP_CIPHER *)EVP_aes_256_cfb();

EVP_CIPHER_CTX_init(&enc_ctx);

EVP_EncryptInit_ex(&enc_ctx, cipher, NULL, key, iv);

EVP_EncryptUpdate(&enc_ctx, ciphertext, &c_len, plaintext, len);

EVP_CIPHER_CTX_cleanup(&enc_ctx);

printf("the openssl ciphertext is %s\\n",ciphertext);

return 0;

}

hope someone can give me a help

[IDZ_A_Intel]

Hi Chen,

We can reproduce the problem andare investigating it. Get back to you soon.

Regards,
Ying

[Ying_H_Intel]

Hi Chen,

I'm afraid the OpenSSL AES EVP_CIPHER *cipher=(EVP_CIPHER *)EVP_aes_256_cfb() are notexactly equivalent to the IPP Rigndael256 here.

IPP Rigndael256 means implementation of general Rijndael algorithm with 256 bit data block size.
If i haven't made mistake, OpenSSL aes 256 are based on CFB 128bit.
/* crypto/evp/evp.h */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
# define EVP_aes_256_cfb EVP_aes_256_cfb128

So the result is different.

You may Use IPP Rijndael128 instead. For example , change the code as below.

//--------------------encrypt with ipp----------------------------
ippsRijndael128GetSize(&ctxsize);
IppsRijndael128Spec* pCtx = (IppsRijndael128Spec*)(new Ipp8u [ctxsize]);
ippsRijndael128Init(key,IppsRijndaelKey128,pCtx);//??????
IppStatus status=ippsRijndael128EncryptCFB(plaintext,ciphertext,len,16,pCtx,iv,NONE); //Size of the CFB block is128bit.

EVP_CIPHER *cipher=(EVP_CIPHER *)EVP_aes_128_cfb();
Then you may get same result.

Regards,
Ying

[Ying_H_Intel]

One more discussion at http://software.intel.com/en-us/forums/showthread.php?t=75650, AES Cryptography Primitive Malfunctioning?
where Andrzej Ch giveawonderfulexplanation and sample.

Reagards,
Ying