import socket
import re

host = '110.41.145.99'
port = 8005
def Tostr(st):
    return st.encode(encoding='UTF8')

def connect():
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect((host,port))
    return s

def getCliphertext(data):
    p1 = r"(>)(.*?)(\r\n)"
    pattern1 = re.compile(p1)
    data = pattern1.findall(data)[0][1]
    return data

def get_pad_len(s):
    s.recv(1024)
    for i in range(1,16):
        payload1 = "encrypt "+'a'*i
        s.send(Tostr(payload1))
        data = (s.recv(1024)).decode('utf-8')
        data = getCliphertext(data)
        if i==1:
            slen = len(data)
        if len(data)>slen:
            break
    return i-1

def forcerFlag(s,slen):
    padd = 'a'*(slen+1)
    plaintext = ""
    print("start...")
    array = "`1234567890-=+qwertyuiop[]asdfghjkl;'zxcvbnm,./?<>!@#$%^&*()QWERTYUIOP{}ASDFGHJKLZXCVBNM:"
    for i in range(19):
        for ch in array:
            payload2 = "encrypt "+ch+plaintext+'*'*15+padd
            s.send(Tostr(payload2))
            data = (s.recv(1024)).decode('utf-8')
            data = getCliphertext(data)
            bp = data[:32]
            sec = data[96:128]
            if bp==sec:
                plaintext = ch +plaintext
                print(plaintext)
                break
    return plaintext

def exp():
    s = connect()
    slen = get_pad_len(s)
    plaintext = forcerFlag(s,slen)
    print(plaintext)

if __name__ == '__main__':
    exp()