有的CTF题目需要爆破sha256字符串的前四位，如果写暴力脚本则效率较低，提前生成字符串可以提高效率
只需要更改sha256和tail即可运行
import hashlib
import itertools
from string import digits, ascii_letters, punctuation
alpha_bet=digits+ascii_letters+punctuation
strlist = itertools.product(alpha_bet, repeat=4)
sha256="a645e3deef85766e43c8a1aa63d1f69eed55e7cb94f10973bd76a9ace57c7311"
tail="amLSvne0g1ypVG5J"
xxxx=''
for i in strlist:
data=i[0]+i[1]+i[2]+i[3]
data_sha=hashlib.sha256((data+str(tail,encoding='utf-8')).encode('utf-8')).hexdigest()
if(data_sha==str(sha256,encoding='utf-8')):
xxxx=data
break
print(xxxx)