Hi,
Thanks for the reply. I have my sample test case like this.
#define KEYSIZE 256
#define AES_BLOCK_SIZE 32
void test_main()
{
char key[KEYSIZE+1];
int I,keylen;
char data[AES_BLOCK_SIZE] ;
char cbuf[AES_BLOCK_SIZE];
char pbuf[AES_BLOCK_SIZE];
strcpy(key,"2ea24d27bc6e40e70b0a2ab08b0831675cf1274834f98a58709edeeb56af
f547");
strcpy(data,"00000000000000000000000000000000000000000000000000000000000
00000");
keylen = strlen(key);
{
AES_KEY ctx;
unsigned char iv[AES_BLOCK_SIZE];
memset(cbuf, 0,AES_BLOCK_SIZE);
AES_set_encrypt_key(key, KEYSIZE, &ctx);
AES_cbc_encrypt(data, cbuf, AES_BLOCK_SIZE, &ctx, iv,
AES_ENCRYPT);
for (i =0 ; i <sizeof(data) ; i++)
printf("%d...input = %d \n",data[i],i);
printf("\n");
for (i =0 ; i <sizeof(cbuf); i++)
printf("%d...encoded data =%d \n",cbuf[i],i);
printf("\n");
}
{
AES_KEY ctx;
int len,pad,flag =0;
unsigned char iv[AES_BLOCK_SIZE];
memset(pbuf, 0,AES_BLOCK_SIZE);
memset(iv, 0, AES_BLOCK_SIZE);
AES_set_decrypt_key(key, KEYSIZE, &ctx);
AES_cbc_encrypt(cbuf,pbuf, AES_BLOCK_SIZE, &ctx, iv,
AES_DECRYPT);
}
}
Please can any tell me what could be the problem with this code?
Regards,
Jaya.
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Marek Marcola
Sent: Monday, September 18, 2006 3:39 PM
To: [email protected]
Subject: Re: How do I remove padding during AES decryption
Hello,
> Please can any one tell me how do I remove the pad bytes during AES
> decyrption using AES_cbc_encryption.
Provided that block_size is size of encryption algorithm block size and
last block is in dst you may use something like that:
.
.
pad = dst[block_size - 1];
if (pad > block_size) {
goto err;
}
for (i = 1; i < pad; i++) {
if (dst[block_size - 1 - i] != pad) {
goto err;
}
}
len = block_size - pad;
.
.
Proper length is returned in len.
Best regards,
--
Marek Marcola <[EMAIL PROTECTED]>
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______________________________________________________________________
OpenSSL Project http://www.openssl.org
User Support Mailing List [email protected]
Automated List Manager [EMAIL PROTECTED]
