decryption.py

import threading, os, signal, hashlib, base64, sys

iterations = 1000
DIV = 2500
begin = [0, 1000, 2500, 5000, 7500]
quit = False

def signalHandler(signo, arg):
    global quit
    quit = True
    #print("Receive a signal %d, quit %d" %(signo, quit))

def findPasswd(hashStr, saltStr):
    "Find the password of the Parental Contol"
    signal.signal(signal.SIGTERM, signalHandler)
    signal.signal(signal.SIGINT, signalHandler)
    if os.path.exists("result.txt"):
        os.remove("result.txt")

    task_list = []

    t1 = threading.Thread(target=matchSmallNumberHash,args=(1000, hashStr, saltStr))
    task_list.append(t1)
    t2 = threading.Thread(target=matchHash,args=(2500, hashStr, saltStr))
    task_list.append(t2)
    t3 = threading.Thread(target=matchHash,args=(5000, hashStr, saltStr))
    task_list.append(t3)
    t4 = threading.Thread(target=matchHash,args=(7500, hashStr, saltStr))
    task_list.append(t4)
    t5 = threading.Thread(target=matchHash,args=(10000, hashStr, saltStr))
    task_list.append(t5)
    
    for t in task_list:
        t.start()
    for t in task_list:
        t.join()

def getHash(key, salt):
    Hash = hashlib.pbkdf2_hmac('sha1', bytes(key.encode()), base64.b64decode(salt), iterations)
    Hash = base64.b64encode(Hash)
    return Hash

def sendSignal():
    os.kill(os.getpid(), signal.SIGINT)

def compare(newStr, oldStr, passwd):
    if newStr == bytes(oldStr.encode()):
        print("****** Found it!!!!! ****** The password is ", passwd)
        with open("result.txt", "w") as f:
            BUF = "Password: " + passwd + "\n"
            f.write(BUF)
        sendSignal()
        return True

    return False

def matchSmallNumberHash(count, hashStr, saltStr):
    keyStr = ""
    global quit
    for i in range(0, 10):
        keyStr = "000" + str(i)
        newHash = getHash(keyStr, saltStr)
        compare(newHash, hashStr, keyStr)
        if (quit):
            return

    for i in range(10, 100):
        keyStr = "00" + str(i)
        newHash = getHash(keyStr, saltStr)
        compare(newHash, hashStr, keyStr)
        if (quit):
            return
   
    for i in range(100, count):
        keyStr = "0" + str(i)
        newHash = getHash(keyStr, saltStr)
        compare(newHash, hashStr, keyStr)
        if (quit):
            return
            
def matchHash(count, hashStr, saltStr):
    "Compare the new hash which generated by key & salt with hashStr"
    global quit
    for i in range(begin[int(count/DIV)], count):
        newHash = getHash(str(i), saltStr)
        compare(newHash, hashStr, str(i))
        if (quit):
            return

def usage():
    print("Usage:")
    print("      %s \"axo6VEI3Tn2ekTeLxA8KBBmH7CA=\" \"GuCyTQ==\"" % sys.argv[0])

def main():
    if len(sys.argv) == 3:
        hashKey = sys.argv[1]
        salt = sys.argv[2]
        if len(hashKey) != 28 or len(salt) != 8:
            print("Please input the right Hash key and salt value!")
            usage()
            return

        findPasswd(hashKey, salt)
        if not quit:
            print("Sorry, cannot find the password for this hash key and salt!!!")
            print("Please check the hash key and salt are right or not!")
    else:
        print("Please input the right arguments!!")
        usage()

# Call the main function
main()