Blowfish.cpp

/*
 * blowfish.cpp
 *
 *  Created on: Aug 24, 2017
 *      Author: xvas
 */



/*
	 * The glibc2 version of crypt(3) function supports additional encryption
       algorithms.

	   If salt or seed in this case is a character string starting with the characters "$id$"
       followed by a string terminated by "$":

              $id$salt$encrypted

       then instead of using the DES machine, id identifies the encryption
       method used and this then determines how the rest of the password
       string is interpreted.

       The following values of id are supported:

              ID  | Method
              ─────────────────────────────────────────────────────────
              1   | MD5
              2a  | Blowfish (not in mainline glibc; added in some
                  | Linux distributions)
              5   | SHA-256 (since glibc 2.7)
              6   | SHA-512 (since glibc 2.7)

       in this case $1$salt$encrypted is an MD5 encoded one.

       The characters in "salt" (seed) and "encrypted" are drawn from the set
       [a-zA-Z0-9./].  In the MD5 and SHA implementations the entire key is
       significant.

       salt or seed in this case  is a two-character string chosen from the set [a-zA-Z0-9./].
       This string is used to perturb the algorithm in one of 4096 different
       ways.

	Security Concerns
	------------------

	   Warning: the key space consists of 2**56 equal 7.2e16 possible
       values.  Exhaustive searches of this key space are possible using
       massively parallel computers.

	   Software, such as crack(1), is  available which will search the portion of this key space that is
       generally used by humans for passwords.  Hence, password selection should, at minimum, avoid common words and names.  The use of a
       passwd(1) program that checks for crackable passwords during the selection process is recommended.

       MD5 algorithm should not be choosed because is vulnerable to colission attacks

	 */


#include "Blowfish.h"
#include <QMessageBox>
#include <unistd.h>
#include <crypt.h>


IHashing *Blowfish::Create()
{
	return new Blowfish();
}

void Blowfish::Free()
{
	delete this;
}

/* Hashing */

char *Blowfish::encryptpass( QString passwd) const
{
	HashEncode *hEnc = new HashEncode();
	//το seed είναι το αναγνωριστικό του αλγόριθμου blowfish($2a$)
	static char seed[7];
	seed[0] = '$';
	seed[1] = '2';
	seed[2] = 'a';
	seed[3] = '$';
	//παράγει διαφορετικά σετ απο ψευδοτυχαίους αριθμούς κάθε φορά που το πρόγραμμα τρέχει
	//Στη συνέχεια η random επιστρέφει τυχαίους αριθμούς ανάλογα με το σετ που έχει δημιουργηθεί απο τη srandom
	srandom ( ( int ) time ( ( time_t * ) NULL ) );
	hEnc->into64 ( &seed[4], random(),saltLength );
	hEnc->into64 ( &seed[saltLength],random(),4 );
	seed[saltLength+4] = '$';

	if (hEnc != nullptr )
		{delete hEnc;
		hEnc = nullptr;}

	char *buf = ( char * )calloc ( 512, sizeof(*buf) );
	char *password = passwd.toLatin1().data();
    memcpy ( buf,password,strlen(password));

	/*
	 * The crypt_r function does the same thing as crypt, but takes an extra parameter
	 * which includes space for its result (among other things), so it can be reentrant.
	 * data->initialized must be cleared to zero before the first time crypt_r is called
	 */

	struct crypt_data data;
	data.initialized = 0;

	char *pass = crypt_r ( buf,seed, &data);

	if ( pass == NULL )
		QMessageBox::critical ( 0,QObject::tr ( "User Manager" ),QObject::tr ( "%1" ).arg ( ENOSYS ) );
	if (buf!=NULL)free(buf);
	return strdup ( pass );
}