SHA256密码碰撞

#-*- coding:utf-8 -*-
import string
import hashlib
import time
import threading
import sys
sha256 = "fcba016ea2ad95a6b824ed4e21befa491c1d1232872c67391f4fdecf086ad4e1"
strr="ABCDEFGHIJKMLNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"

def main1(asc1):
    def main2(asc2):
        def main3(asc3):
            def main4(asc4):
                asc = asc1+asc2+asc3+asc4
                proof=asc+"suHitdzjXxVxxGa7" 
                digest = hashlib.sha256(proof.encode('utf-8')).hexdigest()
                if digest == sha256:
                    zhi ='\n\n\n\n\n\n\n\n\n\n-------------------------------------\n'+proof+'\n'+digest+'\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n'
                    f = open("zhi.txt",'w')
                    f.write(zhi)
                    f.close()
                    print '\n\n\n\n\n\n\n\n\n\n-------------------------------------'
                    print proof+'\n'+digest+'\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n'
                    sys.exit(0)
                    return 
                else:
                    day = time.asctime(time.localtime(time.time()))
                    print "当前时间为：" + day+'\n'
                    print proof+"\n"+digest+"\n"
            for asc4 in strr:
                t4 = threading.Thread(target=main4,args=(asc4,))
                t4.start()    
        for asc3 in strr:
            t3 = threading.Thread(target=main3,args=(asc3,))
            t3.start()
    for asc2 in strr:
        t2 = threading.Thread(target=main2,args=(asc2,))
        t2.start()
for asc1 in strr:
    t1 = threading.Thread(target=main1,args=(asc1,))
    t1.start()