Encrypted line changes on each run .

[Jabka Atu]

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Hash: SHA1

I wrote a small application to understand ARCFOUR use .


for some reason the encrypted text changes each time i run it :

So if i store it in a file and read it from file after 30 minuts i
can't decrypt it .


but if i run this as it is it works fine


#include <stdio.h>
#include <gcrypt.h>
#include <assert.h>

int read2 ( char * filename , char * buffer , size_t size )
{
    FILE * fp = NULL;
    fp = fopen ( filename , "rb" );
    if ( fp == NULL ) return 1;

    fread ( buffer, size, 1, fp );
    fclose ( fp );
}

int write2 ( char * filename , char * buffer , size_t size )
{
    FILE * fp = NULL;
    fp = fopen ( filename , "wb" );
    if ( fp == NULL ) return 1;
    fwrite ( buffer, size, 1, fp );
    fclose ( fp );
}


int main()
{

    gcry_cipher_hd_t handle;
    gcry_cipher_hd_t handle2;
    gcry_error_t err = 0;
    char * plain_text ;
    char * out ;
    char * deout ;
    int i ;
    char  key[] = "This is really strange , i read the documentation i
googled for two days and nothing , i can't encrypt && decrypt";
    char text[] = "Text to encrypt bla bla bla bla bla bla bla soo
This is really strange , i read the documentation i googled for two
days and nothing , i can't encrypt && decrypt";

    size_t size_of_plain_text    =  strlen ( text ) + 1;
    size_t size_of_buffers        =  size_of_plain_text ;

    plain_text = ( char * ) malloc ( size_of_plain_text );
    out = ( char * ) malloc ( size_of_buffers );
    deout = ( char * ) malloc ( size_of_buffers );


    assert ( plain_text );

    assert ( out );
    assert ( deout );


    //Just null all

    for ( i = 0 ;i < size_of_buffers; i++ )
    {
        out[i] = '0';
        deout[i] = '0';
    }

    strcpy ( plain_text , text );


    gcry_check_version ( NULL );
    gcry_control ( GCRYCTL_DISABLE_SECMEM_WARN );
    gcry_control ( GCRYCTL_INIT_SECMEM, 16384, 0 );


    {

        err = gcry_cipher_open ( &handle2,
GCRY_CIPHER_ARCFOUR,GCRY_CIPHER_MODE_STREAM,0 );
        err = gcry_cipher_open ( &handle,
GCRY_CIPHER_ARCFOUR,GCRY_CIPHER_MODE_STREAM,0 );

        if ( err )
        {
            fprintf ( stderr, "Failure: %s/%s\n",
                      gcry_strsource ( err ),
                      gcry_strerror ( err ) );

        }
        err = gcry_cipher_setkey ( handle  , key ,256 );
        err = gcry_cipher_setkey ( handle2 , key,256 );
        if ( err )
        {
            fprintf ( stderr, "Failure: %s/%s\n",
                      gcry_strsource ( err ),
                      gcry_strerror ( err ) );

        }
    }
    err =  gcry_cipher_encrypt ( handle,
                                 ( unsigned char * ) out,
size_of_buffers , ( const unsigned char * )
plain_text,size_of_plain_text );
    if ( err )
    {
        fprintf ( stderr, "Failure: %s/%s\n",
                  gcry_strsource ( err ),
                  gcry_strerror ( err ) );

    }

    write2 ( "/tmp/encrypt",out,size_of_buffers );
    for ( i = 0 ;i < size_of_buffers; i++ )
        out[i] = '0';
    read2 ( "/tmp/encrypt",out,size_of_buffers );
    err =  gcry_cipher_encrypt ( handle2,
                                 ( unsigned char * ) deout,
size_of_buffers, ( const unsigned char * ) out,size_of_buffers );
    if ( err )
    {
        fprintf ( stderr, "Failure: %s/%s\n",
                  gcry_strsource ( err ),
                  gcry_strerror ( err ) );

    }
    printf ( "The result is : %d\n%s\n%s\n", strcmp ( deout,text
),deout , text );

    free ( plain_text );
    free ( out );
    free ( deout );
    gcry_cipher_close ( handle );
    gcry_cipher_close ( handle2 );
    return 0;

}

- --
- ---==== Jabka Atu ===---
    bsh83.blogspot.com
- ---=== Encryption is a way of life ===---
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