2020华为HWS选拔赛WP

from hashlib import sha256
import signal

def s2b(s):
    res = b''
    for i in s:
        res += bytes([ord(i)])
    return res


def b2s(b):
    s = ''
    for i in b:
        s += chr(i)
    return s

class Hash():

    def __init__(self):
        self.h =    144066263297769815596495629667062367629
        self.g =    (1 << 88) + 315 #309485009821345068724781371                
        self.mask = 0xffffffffffffffffffffffffffffffff #340282366920938463463374607431768211455
    
    def encode(self,message):
        message = [ord(i) for i in message]
        h = self.h
        for i in message:
            h = ((h+i)*self.g)&self.mask
        return h


class Task(BaseRequestHandler):


    def dosend(self, msg):
        try:
            self.request.sendall(msg)
        except:
            pass

    def recvall(self, sz):
        try:
            r = sz
            res = ""
            while r > 0:
                res += b2s(self.request.recv(r))
                if res.endswith("\n"):
                    r = 0
                else:
                    r = sz - len(res)
            res = res.strip()
        except:
            res = ""
        return res.strip("\n")

    def proof_of_work(self):
        random.seed(os.urandom(8))
        proof = ''.join([random.choice(string.ascii_letters+string.digits) for _ in range(20)])
        digest = sha256(proof.encode()).hexdigest()
        self.request.send(s2b(("sha256(XXXX+%s) == %s\n" % (proof[4:],digest))))
        self.request.send(b'Give me XXXX:')
        x = self.request.recv(10)
        x = b2s(x)
        x = x.strip()
        if len(x) != 4 or sha256((x+proof[4:]).encode()).hexdigest() != digest: 
            return False
        return True

    def handle(self):
        
        signal.alarm(300)
        if not self.proof_of_work():
   		    return
        signal.alarm(300)

        self.dosend(b"welcome to eZLogin System!\n")
        admin = "admin_is_badmonkey"
        hash = Hash()
        sig = str(hash.encode(admin))               
        self.dosend("admin's signature is: ")
        self.dosend(s2b(sig+'\n'))                      #62198197517637162159907352106958695418
        try:
            while True:
                self.dosend(b"Options\n")
                self.dosend(b"1.Login\n")
                self.dosend(b"2.Register\n")
            
                choice = int(self.recvall(1024))
                if choice != 1 and choice != 2:
                    self.dosend(b"no such choice\n")
                    break
                if choice == 1:
                    self.dosend(b"give me your username(hex)\n")
                    username = self.recvall(1024)
                    username = b2s(bytes.fromhex(username))
                    usersig = str(hash.encode(username))
                    print(username)
                    if username == admin :
                        self.dosend(b"sorry,you are not badmonkey\n")
                        break
                    if usersig == sig:
                        self.dosend(b"welcome,badmonkey\n")
                        self.dosend(flag)
                        break
                    else:
                        self.dosend(s2b("welcome,{}\n".format(username)))
                else:
                    self.dosend(b"give me your username(hex)\n")
                    username = self.recvall(1024)
                    username = b2s(bytes.fromhex(username))

                    usersig = str(hash.encode(username))
                    self.dosend(b"Here is your signature\n")
                    self.dosend(s2b(usersig+'\n'))
        except e:
            print(e)
            self.dosend(b"wrong input\n")
            return False

        



if __name__ == '__main__':
    HOST, PORT = "0.0.0.0", 9999
    server = ThreadingTCPServer((HOST, PORT), Task)
    server.allow_reuse_address = True
    server.serve_forever()

# sha256(4aHR WmCfG8o5dCsQlbXg) == d06abb600b3854aa5bcd61cf30aceac06016f93822d9097e1d9bbfa908d38fca

password = "WyctX8tEbHegSagN"
dig = "25870d38f20b7702cf9f7275e4c19182eb7bdcc62dad954119e2ec6a547bfee5"

dic = "1234567890QWERTYUIOPASDFGHJKLZXCVBNMqwertyuiopasdfghjklzxcvbnm"

for a in dic:
    for b in dic:
        for c in dic:
            for d in dic:
                gantama = a+b+c+d+password
                # print(gantama)
                if(sha256(gantama.encode()).hexdigest()==dig):
                    print(a+b+c+d)
                    exit()

from sage.all import *

mod = 2**128
h0 = 144066263297769815596495629667062367629
g = 2**88 + 315

K = 2**128
B = K**2 # big enough

if 1: # short collision
    N = 17           # number of bytes
    base = [128] * N # close to this value
    '''
    [128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128]
    ASCII: '\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80'
    0xfa3824bfb69587b859aa5b77536cd63fL
    [192, 123, 55, 93, 181, 109, 138, 206, 172, 80, 67, 129, 208, 102, 150, 56, 159]
    ASCII: '\xc0{7]\xb5m\x8a\xce\xacPC\x81\xd0f\x968\x9f'
    0xfa3824bfb69587b859aa5b77536cd63fL
    '''

else: # readable (second preimage)
    base = map(ord, "~~~~ NSU CRYPTO IS FUN! ~~~~")
    N = len(base)
    '''
    [126, 126, 126, 126, 32, 78, 83, 85, 32, 67, 82, 89, 80, 84, 79, 32, 73, 83, 32, 70, 85, 78, 33, 32, 126, 126, 126, 126]
    ASCII: '~~~~ NSU CRYPTO IS FUN! ~~~~'
    0x8e10c895b91c6cba80b57a5e555b7f6L
    [130, 133, 123, 131, 39, 76, 87, 83, 30, 68, 82, 78, 73, 86, 75, 23, 83, 81, 39, 63, 72, 87, 42, 28, 121, 128, 124, 122]
    ASCII: "\x82\x85{\x83'LWS\x1eDRNIVK\x17SQ'?HW*\x1cy\x80|z"
    0x8e10c895b91c6cba80b57a5e555b7f6L
    '''

htarget = 0

m = matrix(ZZ, N + 1, N + 2)
for i in xrange(N):
    ge = pow(g, N-i, mod)
    m[i,0] = ge
    m[i,1+i] = 1
m[N,0] = mod

for i in xrange(N+1):
    m[i,0] *= K

ml = m.LLL()

sol = ml.rows()[0]
print "Sol:", sol
if sol[0] != 0:
    print "Zero not reached, increase K"
    quit()

if not base:
    base = [BASE] * N
msg = []
for i in xrange(N):
    msg.append(base[i] + sol[1+i])
    if not (0 <= msg[-1] <= 255):
        print "Need more bytes!"
        quit()


def FNV2(msg):
    h = h0
    for xi in msg:
        h = (h + xi) * g % mod
    return int(h)


print base
print "ASCII:", `"".join(map(chr, base))`
print hex(FNV2(base)), FNV2(base)
print
print msg
print "ASCII:", `"".join(map(chr, msg))`
print hex(FNV2(msg)), FNV2(base)