def handle(self):
try:
signal.signal(signal.SIGALRM, self.timeout_handler)
signal.alarm(60)
self.send(BANNER)
if not self.proof_of_work():
self.send(b'\nWrong!')
self.request.close()
return
self.send(
b"It's just a decryption system. And I heard that only the Bytedancer can get secret."
)
aes = AES_CFB()
signal.alarm(300)
for i in range(52):
cipher_hex = self.recv(
prompt=b'Please enter your cipher in hex > ')
if len(cipher_hex) > 2048:
self.send(b"It's too long!")
continue
try:
cipher = codecs.decode(cipher_hex, 'hex')
except:
self.send(b'Not hex data!')
continue
if len(cipher) == 0 or len(cipher) % BLOCK_SIZE != 0:
self.send(
f'Cipher length must be a multiple of {BLOCK_SIZE}!'.
encode())
continue
plaintext = aes.decrypt(cipher)
plaintext_hex = codecs.encode(plaintext, 'hex')
self.send(b'Your plaintext in hex: \n%s\n' % plaintext_hex)
if plaintext == b"Hello, I'm a Bytedancer. Please give me the flag!":
self.send(b'OK! Here is your flag: ')
self.send(FLAG.encode())
break
self.send(b'Bye!\n')
except TimeoutError:
self.send(b'\nTimeout!')
except Exception as err:
self.send(b'Something Wrong!')
finally:
self.request.close()
def get_flag(req):
global key
req.sendall(b"Send ciphertext as number:\n")
try:
ciphertext = req.recv(1024).decode().strip()
ciphertext = int(ciphertext)
plaintext = pow(ciphertext, key.d, key.n)
plaintext = long_to_bytes(plaintext)
plaintext = plaintext.decode()
if plaintext == "I want the flag :)":
req.sendall(FLAG.encode() + b"\n")
return
except:
pass
req.sendall(b"Wrong :S\n")
def rsaquine():
total = 30
print '0CTF RSA Quine'
print '%d Rounds in total to capture the flag.' % total
bits = 16
for i in xrange(total):
print 'Round %d' % (i+1)
N,e,qn = gen_param(bits)
bits += 7
print 'N = %d' % N
print 'e = %d' % e
print 'Total %d quine numbers' % qn
if (qn <= 200):
print 'Can you find them?'
else:
qn = 200
print 'Just Give me %d of them.' % qn
quine = set()
for j in xrange(qn):
m = input_int('%d: ' % (j+1))
if m in quine:
print 'Do not cheat!'
exit()
c = pow(m, e, N)
if m == c:
print 'Good Quine!'
quine.add(m)
else:
print 'Bad Number!'
exit()
N,e,qn = gen_param(256)
print 'You are a quine expert!'
print 'N = %d' % N
print 'e = %d' % e
f = pow(int(FLAG.encode('hex'),16), e, N)
print 'Flag = %d' % f
print 'Good Luck & Have Fun!'
def rsaquine():
total = 30
print '0CTF RSA Quine'
print '%d Rounds in total to capture the flag.' % total
bits = 16
for i in xrange(total):
print 'Round %d' % (i + 1)
N, e, qn = gen_param(bits)
bits += 7
print 'N = %d' % N
print 'e = %d' % e
print 'Total %d quine numbers' % qn
if (qn <= 200):
print 'Can you find them?'
else:
qn = 200
print 'Just Give me %d of them.' % qn
quine = set()
for j in xrange(qn):
m = input_int('%d: ' % (j + 1))
if m in quine:
print 'Do not cheat!'
exit()
c = pow(m, e, N)
if m == c:
print 'Good Quine!'
quine.add(m)
else:
print 'Bad Number!'
exit()
N, e, qn = gen_param(256)
print 'You are a quine expert!'
print 'N = %d' % N
print 'e = %d' % e
f = pow(int(FLAG.encode('hex'), 16), e, N)
print 'Flag = %d' % f
print 'Good Luck & Have Fun!'
#!/usr/bin/env python
from Crypto.Util.number import *
from flag import FLAG
def nextPrime(n):
while True:
n += (n % 2) + 1
if isPrime(n):
return n
f = [int(x) for x in bin(int(FLAG.hex(), 16))[2:]]
f.insert(0, 0)
for i in range(len(f) - 1):
f[i] += f[i + 1]
a = nextPrime(len(f))
b = nextPrime(a)
g, h = [[_ for i in range(x) for _ in f] for x in [a, b]]
c = nextPrime(len(f) >> 2)
for _ in [g, h]:
for __ in range(c):
_.insert(0, 0)
for i in range(len(_) - c):
_[i] += _[i + c]
import os,signal
from flag import FLAG
signal.alarm(600)
assert(FLAG.startswith("0ops{"))
assert(FLAG.endswith("}"))
def xor(a,b):
assert(len(a)==len(b))
c = ""
for i in range(len(a)):
c+=chr(ord(a[i])^ord(b[i]))
return c
def encrypt(data):
key = os.urandom(len(data))
return xor(data,key)
print "welcome to sssssssssssssupper safe stream cipher"
while True:
data = raw_input("input your data:").strip()
data = FLAG+data
data = data.encode("zlib")
data = encrypt(data)
print data.encode("hex")
from flag import FLAG
FLAG = int(FLAG.encode('hex'),16)
P = 0xd3ceec4c84af8fa5f3e9af91e00cabacaaaecec3da619400e29a25abececfdc9bd678e2708a58acb1bd15370acc39c596807dab6229dca11fd3a217510258d1b
A = 0x95fc77eb3119991a0022168c83eee7178e6c3eeaf75e0fdf1853b8ef4cb97a9058c271ee193b8b27938a07052f918c35eccb027b0b168b4e2566b247b91dc07
Gx = 0xcf634030986cf41c1add87e71d638b9cc723c764059cf4c9b8ed2a0aaf5d51dc770372503ebfaad746ab9220e992c09822916978226465ad31d354a3efee51da
Gy = 0x65eaad8848b2787103fce02358b45d8a61420031989eb6b4b70d82fe20d85583ae542eb8f76749dc640b0f13f682228819b8b2f04bd7a5a17a4c675540fe1c90
assert FLAG < P
def egcd(a, b):
x,y, u,v = 0,1, 1,0
while a != 0:
q, r = b//a, b%a
m, n = x-u*q, y-v*q
b,a, x,y, u,v = a,r, u,v, m,n
gcd = b
return gcd, x, y
def inv(a):
gcd, x, y = egcd(a % P, P)
if gcd != 1:
return -1
else:
return x % P
def add(a, b):
if a == 0:
return b
if b == 0:
return a
from flag import FLAG
FLAG = int(FLAG.encode('hex'), 16)
P = 0xd3ceec4c84af8fa5f3e9af91e00cabacaaaecec3da619400e29a25abececfdc9bd678e2708a58acb1bd15370acc39c596807dab6229dca11fd3a217510258d1b
A = 0x95fc77eb3119991a0022168c83eee7178e6c3eeaf75e0fdf1853b8ef4cb97a9058c271ee193b8b27938a07052f918c35eccb027b0b168b4e2566b247b91dc07
Gx = 0xcf634030986cf41c1add87e71d638b9cc723c764059cf4c9b8ed2a0aaf5d51dc770372503ebfaad746ab9220e992c09822916978226465ad31d354a3efee51da
Gy = 0x65eaad8848b2787103fce02358b45d8a61420031989eb6b4b70d82fe20d85583ae542eb8f76749dc640b0f13f682228819b8b2f04bd7a5a17a4c675540fe1c90
assert FLAG < P
def egcd(a, b):
x, y, u, v = 0, 1, 1, 0
while a != 0:
q, r = b // a, b % a
m, n = x - u * q, y - v * q
b, a, x, y, u, v = a, r, u, v, m, n
gcd = b
return gcd, x, y
def inv(a):
gcd, x, y = egcd(a % P, P)
if gcd != 1:
return -1
else:
return x % P
def add(a, b):
if a == 0:
from Crypto.Cipher import AES
from flag import FLAG
r = len(FLAG) % 16
f = FLAG.ljust(len(FLAG) + 16 - r).encode()
key = b'testtesttesttest'
cipher = AES.new(key, AES.MODE_ECB)
c = cipher.encrypt(f).hex()
open('output.txt', 'w').write(f'{c}')
L=2048-N-1
while True:
q = getPrime(N)
if q-1>x:
break
assert(q-1>x)
while True:
t = random.getrandbits(L)
p = (t * 2*q + 1)
if isPrime(p):
break
e = (p-1) // q
g = pow(2, e, p)
y = pow(g, x, p)
print("genkey_finish!")
return {'y':y, 'g':g, 'p':p, 'q':q, 'x':x}
def sign(m, key):
g, p, q, x = key['g'], key['p'], key['q'], key['x']
k = random.randint(1, q-1)
Hm = int.from_bytes(hashlib.md5(str(m).encode('utf-8')).hexdigest().encode(), 'big')
r = pow(g, k, p) % q
s = (inverse(k, q) * (Hm + x*r)) % q
return (r, s, k, q)
if __name__ == "__main__":
msg=int.from_bytes(FLAG.encode(),'big')
rsaEncode(msg)
def __init__(self):
self.gen = 0x44120dc98545c6d3d81bfc7898983e7b7f6ac8e08d3943af0be7f5d52264abb3775a905e003151ed0631376165b65c8ef72d0b6880da7e4b5e7b833377bb50fde65846426a5bfdc182673b6b2504ebfe0d6bca36338b3a3be334689c1afb17869baeb2b0380351b61555df31f0cda3445bba4023be72a494588d640a9da7bd16L
self.q = 0x926c99d24bd4d5b47adb75bd9933de8be5932f4bL
self.p = 0x80000000000001cda6f403d8a752a4e7976173ebfcd2acf69a29f4bada1ca3178b56131c2c1f00cf7875a2e7c497b10fea66b26436e40b7b73952081319e26603810a558f871d6d256fddbec5933b77fa7d1d0d75267dcae1f24ea7cc57b3a30f8ea09310772440f016c13e08b56b1196a687d6a5e5de864068f3fd936a361c5L
self.key = int(FLAG.encode("hex"), 16)
