$1.$ Password cracking using multithreading $(15\%-100$ marks$)-$ PThread

In this task, you will be asked to use the $$crypt$$ library to decrypt a password using multithreading. You will be provided with two programs. The first program called $$EncryptSHA$512.$c$$ which allows you to encrypt a password. For this assessment, you will be required to decrypt a $4-$character password consisting of $2$ capital letters, and $2$ numbers. The format of the password should be $$LetterLetterNumberNumber$.$ For example, $$PK$94.$ Once you have generated your password, this should then be entered into your program to decrypt the password. The method of input for the encrypted password is up to you. The second program is a skeleton code to crack the password in regular C without any multithreading syntax. Your task is to use multithreading to split the workload over many threads and find the password. Once the password has been found, the program should finish meaning not all combinations of $2$ letters and $2$ numbers should be explored unless it$$s ZZ$99$ and the last thread happens to finish last.

Cracks a password using multithreading and dynamic slicing based on thread count $(75$ marks$)$

Program finishes appropriately when password has been found $(25$ marks$)$

$$

$$I$$ve already generated the encrypted string for the password $"$PK$94"$ using EncryptSHA$512.$c and added it to the CrackAZ$99.$c program.

The encrypted string is:

$$6$$AS$$95$zARikIkblIv$8$WVGg$31$dz$2$SJALGK$1$DoFQsi$5$e$1$m$1$bp$0$zzQJ$4$gbTgJqb$6$iG$6$uxOert$6$UKQO.vlLmCsTM$.$uLWi$1$

The file I was given, EncryptSHA$512.$c

#include

#include

#include

#include

#include

#define SALT $"$$$6$$AS$$"$

int main$($int argc, char $*$argv$[])\{$

$$

$$ printf$("\%$s

$",$ crypt$($argv$[1],$ SALT$))$;

$$ return $0$;

$\}$

and this one, CrackAZ$99.$c

#include

#include

#include

#include

#include

int count$=0$; $//$ A counter used to track the number of combinations explored so far

$/**$

$$Required by lack of standard function in C$.$

$*/$

void substr$($char $*$dest$,$ char $*$src$,$ int start, int length$)\{$

$$ memcpy$($dest$,$ src $+$ start, length$)$;

$*($dest $+$ length$)=\text{'}\backslash 0\text{'}$;

$\}$

$/**$

$$This function can crack the kind of password explained above. All combinations

$$that are tried are displayed and when the password is found, #$,$ is put at the

$$start of the line. Note that one of the most time consuming operations that

$$it performs is the output of intermediate results, so performance experiments

$$for this kind of program should not include this. i$.$e$.$ comment out the printfs.

$*/$

void crack$($char $*$salt$\_$and$\_$encrypted$)\{$

$$ int x$,$ y$,$ z; $//$ Loop counters

$$ char salt$[7]$; $//$ String used in hashing the password. Need space for $\backslash 0//$ incase you have modified the salt value, then should modifiy the number accordingly

$$ char plain$[7]$; $//$ The combination of letters currently being checked $//$ Please modifiy the number when you enlarge the encrypted password.

$$ char $*$enc; $//$ Pointer to the encrypted password

$$ substr$($salt$,$ salt$\_$and$\_$encrypted, $0,6)$;

$$ for$($x$=\text{'}$A$\text{'}$; x$<=\text{'}$Z$\text{'}$; x$++)\{$

$$ for$($y$=\text{'}$A$\text{'}$; y$<=\text{'}$Z$\text{'}$; y$++)\{$

$$ for$($z$=0$; z$<=99$; z$++)\{$

$$ sprintf$($plain$,"\%$c$\%$c$\%02$d$",$ x$,$ y$,$ z$)$;

$$ enc $=($char $*)$ crypt$($plain$,$ salt$)$;

$$ count$++$;

$$ if$($strcmp$($salt$\_$and$\_$encrypted, enc$)==0)\{$

$$ printf$("$#$\%-8$d$\%$s $\%$s

$",$ count, plain, enc$)$;

$//$return; $//$uncomment this line if you want to speed$-$up the running time, program will find you the cracked password only without exploring all possibilites

$\}$else$\{$

$$ printf$("\%-8$d$\%$s $\%$s

$",$ count, plain, enc$)$; $//$when the password is not found

$\}$

$\}$

$\}$

$\}$

$\}$

int main$($int argc, char $*$argv$[])\{$

$$ crack$("$$$6$$AS$$95$zARikIkblIv$8$WVGg$31$dz$2$SJALGK$1$DoFQsi$5$e$1$m$1$bp$0$zzQJ$4$gbTgJqb$6$iG$6$uxOert$6$UKQO.vlLmCsTM$.$uLWi$1")$; $//$Copy and Paste your ecrypted password here using EncryptShA$512$ program

$$ printf$("\%$d solutions explored

$",$ count$)$;

$$ return $0$;

$\}$