#cryptoctf2021 # Elliptic curve basics, tools for finding rational points, and ECDSA implementation. # Brendan Cordy, 2015 from fractions import Fraction from math import ceil, sqrt from random import SystemRandom, randrange from hashlib i…

#cryptoctf2021 #!/usr/bin/env sage from Crypto.Util.number import * from secret import flag, Curve def ison(C, P): c, d, p = C u, v = P return (u**2 + v**2 - c**2 * (1 + d * u**2*v**2)) % p == 0 def teal(C, P, Q): c, d, p = C u1, v1 = P u2…

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * from math import gcd from flag import flag def keygen(p): while True: u = getRandomRange(1, p) if pow(u, (p-1) // 2, p) != 1: break x = getRandomRange(1, p) w = pow(u, …

#cryptoctf2021 | Options: | [P]rint encrypted flag | [R]eveal the parameters | [Q]uit R e = 65537 isPrime(p) = True isPrime(q) = True n = p * q (p - 909)**2 + (q - 90)**2 = 162125204943339964168902269001520479235376209518582392527039882716…

#cryptoctf2021 #!/usr/bin/env sage from sage.all import * import string, base64, math from flag import flag ALPHABET = string.printable[:62] + '\\=' F = list(GF(64)) def keygen(l): key = [F[randint(1, 63)] for _ in range(l)] key = math.pro…

#cryptoctf2021 CCTF{Play_with_?aT?X} これ CCTF{Play_with_LaTeX} じゃん，カス #uninterested_challenge_list

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * from random import randint import sys from flag import FLAG def die(*args): pr(*args) quit() def pr(*args): s = " ".join(map(str, args)) sys.stdout.write(s + "\n") sys.…

#cryptoctf2021 #!/usr/bin/env python3 from Cryptodome.Cipher import AES import os import time import sys import random from flag import flag passphrase = b'HungryTimberWolf' def encrypt(msg, passphrase, niv): msg_header = 'EPOCH:' + str(in…

#cryptoctf2021 #!/usr/bin/python3 from Crypto.Util.number import * from gmpy2 import * from secret import * from flag import flag global nbit nbit = 1024 def keygen(nbit): while True: p, q = [getStrongPrime(nbit) for _ in '01'] if p % 4 ==…

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * from gmpy2 import gcd from random import randint import sys import hashlib from flag import flag def lcm(a, b): return (a * b) // gcd(a,b) def gen_params(nbit): p, q = …

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * from flag import flag nbit = 64 while True: p, q = getPrime(nbit), getPrime(nbit) P = int(str(p) + str(q)) Q = int(str(q) + str(p)) PP = int(str(P) + str(Q)) QQ = int(s…

#cryptoctf2021 #!/usr/bin/env python3 from sage.all import * from flag import flag n = 43216667049953267964807040003094883441902922285265979216983383601881964164181 U = 1823029494546684219302946481817610962847341445869345527252784978012143…

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * import sys from flag import flag flag = flag.lstrip('CCTF{').rstrip('}') def query(n, X, E, p): assert n == len(X) > len(E) C = [getRandomRange(0, p) for _ in range(n)]…

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * import sys from flag import flag def tonelli_shanks(n, p): if pow(n, int((p-1)//2), p) == 1: s = 1 q = int((p-1)//2) while True: if q % 2 == 0: q = q // 2 s += 1 else: …

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * from secret import a, b, p, P, Q from flag import flag def onmiff(a, b, p, G): x, y = G return (a*x*(y**2 - 1) - b*y*(x**2 - 1)) % p == 0 def addmiff(X, Y): x_1, y_1 = …

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * from flag import flag l = len(flag) m_1, m_2 = flag[: l // 2], flag[l // 2:] x, y = bytes_to_long(m_1), bytes_to_long(m_2) k = ''' 000bfdc32162934ad6a054b4b3db8578674e2…

#cryptoctf2021 #!/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 r…

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * from hashlib import sha256 import ecdsa from flag import FLAG E = ecdsa.SECP256k1 G, n = E.generator, E.order cryptonym = b'Persian Gulf' def keygen(n, G): privkey = ge…

#cryptoctf2021 #!/usr/bin/env python3 import random from flag import FLAG p = 8443 def transpose(x): result = [[x[j][i] for j in range(len(x))] for i in range(len(x[0]))] return result def vsum(u, v): assert len(u) == len(v) l, w = len(u),…

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * from gmpy2 import * import sys import random import string from flag import FLAG def genrandstr(N): return ''.join(random.choice(string.ascii_uppercase + string.digits …

#cryptoctf2021 m = bytes_to_long(flag) e = 65537 n = p * q = 4024625003400831261259737276316748212140359464095903327962527444430093199954898873916032867176701877865239488518540105913088786921133059927211384908878012962458167444131493813926…

#cryptoctf2021

#cryptoctf2021 #!/usr/bin/env sage from sage.all import * from flag import flag global p, alphabet p = 71 alphabet = '=0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$!?_{}<>' flag = flag.lstrip('CCTF{').rstrip('}') assert l…

#cryptoctf2021 2*z**5 - x**3 + y*z = 4776986470675016158115291926694201488472850430979127230087344076501040568112322405040225388324857174620206043952183535901043915592261861352074741196382234937426014422969875949535959228733108322957236918…

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util.number import * from math import gcd from flag import FLAG def keygen(nbit, dbit): assert 2*dbit < nbit while True: u, v = getRandomNBitInteger(dbit), getRandomNBitInteger(nbit // 2 - …

#cryptoctf2021 #!/usr/bin/env python3 from hashlib import md5, sha1 import sys from secret import salt, pepper from flag import flag assert len(salt) == len(pepper) == 19 assert md5(salt).hexdigest() == '5f72c4360a2287bc269e0ccba6fc24ba' a…

#cryptoctf2021 #!/usr/bin/env python3 from Crypto.Util import number from Crypto.Cipher import AES import os import sys import random from flag import flag def keygen(): iv, key = [os.urandom(16) for _ in '01'] return iv, key def encrypt(m…