Hi Peter,
The extra string in o/p is due to error in coding. u r passing incorrect
length in EVP_DecryptUpdate.
if (!(EVP_DecryptUpdate(&dctx, dec_outbuf, &decoutlen, enc_outbuf,
output_buf_size)))
change above line to
if (!(EVP_DecryptUpdate(&dctx, dec_outbuf, &decoutlen, enc_outbuf,
encoutlen)))
-Shafeek
On Mon, May 2, 2011 at 3:09 PM, derleader mail <derlea...@abv.bg> wrote:
>
> Hi Peter,
> Add padding for CBC mode encryption.
> Or u can use CFB mode. EVB_bf_cfb()
>
> -Shafeek
>
> Hi,
> Thank you for the reply. I have edit the code.
>
> Source Code:
>
> //gcc blowfish2.c -L/usr/local/ssl/lib/ -lssl -lcrypto -Wall
>
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> #include <openssl/evp.h>
> #include <openssl/rand.h>
>
> #define input_buf_size 1024
> #define output_buf_size 1032
>
> int main(int argc, char *argv[])
> {
>
> if (argc !=2)
> {
> printf("Usage: test1 <stringtoencrypt>\n");
> exit(1);
> }
>
> char *string;
>
> int encoutlen, decoutlen, enctotallen, dectotallen;
>
> unsigned char iv[8];
> unsigned char password[16];
> unsigned char enc_outbuf[output_buf_size];
> char enc_inbuf[input_buf_size];
> unsigned char dec_outbuf[input_buf_size];
> char dec_inbuf[output_buf_size];
> EVP_CIPHER_CTX ectx;
> EVP_CIPHER_CTX dctx;
>
> /*
> * Begin the encode - decode
> *
> * Get our inputs and the random IV
> *
> */
>
> string = argv[1];
>
> RAND_bytes(iv, 8);
> RAND_bytes(password, 16);
>
> printf("Entering Encryption Stage:\n\n");
> printf("String to encrypt: %s\n\n", string);
>
> EVP_CIPHER_CTX_init(&ectx);
>
>
> EVP_EncryptInit(&ectx, EVP_bf_cfb(), password, iv);
>
>
> bzero (&enc_inbuf, input_buf_size);
>
> if(!EVP_EncryptUpdate(&ectx, enc_outbuf, &encoutlen, string,
> strlen(string)))
> {
> printf("Error whilst EncryptUpdate\n");
> return 0;
> }
>
> if(!EVP_EncryptFinal(&ectx, enc_outbuf + encoutlen, &enctotallen))
> {
> printf("Error Whilst EncryptFinal\n");
> return 0;
> }
>
> encoutlen += enctotallen;
>
> printf("Encryption Successful\n\n");
> printf("Entering Decryption Stage\n\n");
>
> EVP_CIPHER_CTX_init(&dctx);
> EVP_DecryptInit(&dctx, EVP_bf_cfb(), password, iv);
>
>
> bzero (&dec_inbuf, output_buf_size);
> bzero (&dec_outbuf, input_buf_size);
>
> if (!(EVP_DecryptUpdate(&dctx, dec_outbuf, &decoutlen, enc_outbuf,
> output_buf_size)))
> {
> printf("Error Whilst DecryptUpdate\n");
> return 0;
> }
>
> if (!(EVP_DecryptFinal(&dctx, dec_outbuf + decoutlen,
> &dectotallen)))
> {
> printf("Error Whilst DecryptFinal\n");
> ERR_print_errors_fp(stdout);
> return 0;
> }
>
> decoutlen += dectotallen;
>
> printf("Decryption Successful\n\n");
>
> printf("Decrypted String is: %s\n", dec_outbuf);
>
> return 0;
>
> }
>
>
> This is the output:
>
> [root@localhost test]# ./a.out dcee
> Entering Encryption Stage:
>
> String to encrypt: dcee
>
>
> Encryption Successful
>
> Entering Decryption Stage
>
> Decryption Successful
>
> Decrypted String is: dcee��<�=�͜<I ���C� ���=�t����y�|:�|>s�� � h[j
> �l��ȥg�L^�aPB=�
>
> everytime the string after "dcee" is diffrent. So I need padding.
> Could you edit the source code in proper way. I have no idea how to add
> padding.
>
> Regards
> Peter
>
>
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