Need help for a small brute force application (C-Programming)

I am trying to develop a small brute force application in C. I am using Ubuntu 14.04 as my operating system. My processor is Intel Core i7-920@2.67GHz (stock).

My question is, how can I use MD5_Init, MD5_Update and MD5_Final with openmp without being too careful at runtime?

For example, my main function () - looks like this:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <omp.h>
#include <openssl/md5.h>
#include <time.h>

const char              LiteralsLower[]   = "abcdefghijklmnopqrstuvwxyz";
const int               NLiteralsLower    = sizeof( LiteralsLower ) - 1;
char                    HexByteHash[16];
time_t                  StartTime, EndTime;

/* Prototypes */
static  void            MD5Hash( const char * );
static  void            BruteForce( const int * restrict, const int * restrict, const char *, const int *, int );

int main()
{
    const char HashAsString[] = "172522ec1028ab781d9dfd17eaca4427"; // 'david'
    const int  *BFOptionSize  = &NLiteralsLower;
    const char *BFOption      = LiteralsLower;
    int        PasswordLength = 6;
    int        StrLength      = strlen( HashAsString );

    for( int i = 0; i < StrLength / 2 ; i++ )
    {
        if( !sscanf( HashAsString + 2 * i, "%02x", ( unsigned int * ) &HexByteHash[i] ) )
        {
            fprintf( stderr, "FEHLER!!! -> '%s' ist kein Hash-Wert!\n", HashAsString );
            exit( EXIT_FAILURE );
        }
    }

    fprintf( stdout, "Hash: %s mit einer Länge von %li Zeichen.\n", HashAsString, strlen( HashAsString ) / 2 );

    /* Timer starten */
    time( &StartTime );

    #pragma omp parallel shared( PasswordLength, BFOptionSize )
    for( int PWLength = 0; PWLength < PasswordLength + 1; ++PWLength )
    {
        /* Array-Größe für FstEntry und LstEntry festlegen */
        int FstEntry[PWLength], LstEntry[PWLength];

        /* Array-Felder mit 0 initialisieren */
        for( int j = 0; j < PWLength; ++j )
            FstEntry[j] = LstEntry[j] = 0;

        #pragma omp for schedule( dynamic )
        for( int i = 0; i < *BFOptionSize; ++i )
        {
            FstEntry[0] = i;
            LstEntry[0] = i + 1;
            BruteForce( FstEntry, LstEntry, BFOption, BFOptionSize, PWLength );
        }
    }

    /* Timer stoppen */
    time( &EndTime );

    puts( "!!! Wort nicht gefunden !!!" );

    printf( "Elapsed time: %ld minutes %ld seconds\n\n", ( EndTime - StartTime ) / 60, ( EndTime - StartTime ) % 60 );

    return EXIT_FAILURE;
}

      

        
        
        
      

    

I'm not sure, but I think it's okay so far.

The following code is my bruteforce function:

static void BruteForce( const int * restrict FirstEntry, const int * restrict LastEntry, const char *Letters, const int *NLetters, int PSSWDLength )
{
    char Password[PSSWDLength];
    int  Entry[PSSWDLength + 1];
    int  i, j;

    /* Null-Byte hinzufügen */
    memset( Entry, '\0', PSSWDLength );
    memset( Password, '\0', PSSWDLength );

    /* FirstEntry in Entry kopieren */
    for( i = 0; i < PSSWDLength; ++i )
        Entry[i] = FirstEntry[i];

    i = 0;

    while( i < PSSWDLength )
    {
        /* Generiere Passwort für Hash-Vergleich */
        for( i = 0; i < PSSWDLength; ++i )
            Password[i] = Letters[Entry[i]];

        /* generiertes Wort hashen */
        MD5Hash( Password );

        /* Entry inkrementieren */
        for( i = 0; i < PSSWDLength && ++Entry[PSSWDLength-i-1] == *NLetters; i++ )
            Entry[PSSWDLength-i-1] = 0;

        /* Return wenn Entry != LastEntry raus aus der Schleife */
        for( j = 0; j < PSSWDLength; ++j )
            if( Entry[j] != LastEntry[j] )
                break;

        /* wenn Entry == LastEntry Funktion verlassen */
        if( j == PSSWDLength )
            return;
    }
}

      

        
        
        
      

    

At least my hash function:

static void MD5Hash( const char *PasswordStringPointer )
{
    unsigned char Digest[16];

    /* MD5-Hash erzeugen */
    MD5_CTX md5;
    MD5_Init( &md5 );
    MD5_Update( &md5, PasswordStringPointer, strlen( PasswordStringPointer ) );
    MD5_Final( Digest, &md5 );

    if( memcmp( HexByteHash, Digest, 16 ) == 0 )
    {
        printf( "!!! Wort gefunden: '%s' !!!\n", PasswordStringPointer );

        /* Timer stoppen */
        time( &EndTime );

        printf( "Elapsed time: %ld minutes %ld seconds\n\n", ( EndTime - StartTime ) / 60, ( EndTime - StartTime ) % 60 );

        /* Passwortsuche war erfolgreich */
        exit( EXIT_SUCCESS);
    }
}

      

        
        
        
      

    

The problem is that when I use all of my eight cores, sometimes if I run the application, it doesn't find the word it should be searching for. For example: 172522ec1028ab781d9dfd17eaca4427 <- 'david' <- search word For example, I say max. the length of the words to generate is 6. So ok, when I run the application, I should have this output:

Hash: 172522ec1028ab781d9dfd17eaca4427 mit einer Länge von 16 Zeichen.
!!! Wort gefunden: 'david' !!!
Elapsed time: 0 minutes 1 seconds

      

        
        
        
      

    

But sometimes it happens that I have this output:

Hash: 172522ec1028ab781d9dfd17eaca4427 mit einer Länge von 16 Zeichen.
!!! Wort nicht gefunden !!!
Elapsed time: 0 minutes 14 seconds

      

        
        
        
      

    

This means that for some reason it is not generating the correct hash. Thus, the application runs until "zzzzzz" is generated. I do not understand why.