2023-12-03から1日間の記事一覧
#EllipticCurve from fastecdsa.curve import P521 as Curve from fastecdsa.point import Point from Crypto.Util.number import bytes_to_long, isPrime from os import urandom from random import getrandbits def gen_rsa_primes(G): urand = bytes_to_…
tetctf 2020の問題ほどは面白くなかった印象。同じようなジャンルの問題が偏ると競技者としてはつまらないよね 48時間を3問で持たせるのすごいな
#redpwnctf2021 #uninterested_challenge_list crypto/scissor BrownieInMotion 1005 solves / 102 points I was given this string and told something about scissors. egddagzp_ftue_rxms_iuft_rxms_radymf import random key = random.randint(0, 25) al…
#pbctf_2021 #rbtree #!/usr/bin/env python3 import random from flag import flag def keygen(ln): # Generate a linearly independent key arr = [ 1 << i for i in range(ln) ] for i in range(ln): for j in range(i): if random.getrandbits(1): arr[j…
#corctf2021
from hash import secureHash import SocketServer import string import random from text import * import os from hashlib import sha256 PORT = 2000 ROUNDS = 10 TIMEOUT = 120 sigma = string.ascii_letters + string.digits + "!@#$%^&*()-_=+[{]}<>.…
#UMASS_CTF_2022 #!/usr/bin/env python3 # # Polymero # # Imports import os # Local imports with open('flag.txt','rb') as f: FLAG = f.read() f.close() def bytes_to_mat(x): assert len(x) == 32 bits = list('{:0256b}'.format(int.from_bytes(x,'b…
#tetctf2022 from secrets import randbits from Crypto.Util.number import getPrime # pycryptodome NBITS = 1024 D_NBITS = 128 # small `d` makes decryption faster class Cipher: def __init__(self): p = getPrime(NBITS // 2) q = getPrime(NBITS //…
#CRT
#RubikCube
#TG:HACK2019 Mr. Josefsson wants to test you one last time to see if you are ready for the harder tasks. Can you solve this? good_luck ! 00100011 00100010 00000100 00000010 00001000 00101010 00010111 00001011 00000001 01010101 01010110 000…
#SecurinetsCTFQuals2019 https://ctftime.org/task/7862 https://furutsuki.hatenablog.com/entry/2019/03/25/214238#Crypto-962pts-50-solvesMAZE
#kurenaif #seccon2021 from Crypto.Util.number import * from flag import flag p = getStrongPrime(512) q = getStrongPrime(512) n = p*q mid = len(flag) // 2 e = 65537 m1 = int.from_bytes(flag[:mid], byteorder='big') m2 = int.from_bytes(flag[m…
#xornet #seccon2021 from Crypto.Util.number import bytes_to_long, getPrime, getRandomInteger, isPrime from secret import flag def create_prime(p_bit_len, add_bit_len, a): p = getPrime(p_bit_len) p_bit_len2 = 2*p_bit_len // 3 + add_bit_len …
#rtactf from Crypto.Util.number import getPrime, isPrime import os def getSexyPrime(n=512): # Sexy prime: https://en.wikipedia.org/wiki/Sexy_prime while True: p = getPrime(n) if isPrime(p+6): return p, p+6 if __name__ == '__main__': # Plai…
Ring LWE
https://ctftime.org/task/7777 #pragyanctf #RabinCryptosystem #フェルマー法 Rabin has received a text from someone special, but it's all in ciphertext and he is unable to make head or tail of it. He requested her for a little hint, and she …
https://ctftime.org/task/7821 #pragyanctf Rahul, the geek boy of his class, doesn't like doing things the conventional way. He's just learned polynomials in class, and wants to prove a point to his friend Sandhya. But Sandhya is sitting in…
#inctf2020 sage: p 35201 sage: len(flag) 14 sage: X = int.from_bytes( flag.strip(b'inctf{').strip(b'}') , 'big') sage: n 1629*x^256 + 25086*x^255 + 32366*x^254 + 21665*x^253 + 24571*x^252 + 20588*x^251 + 17474*x^250 + 30654*x^249 + 31322*x…
print(tan(int.from_bytes(open("flag.txt", "rb").read().strip(), "big")).n(1024)) # -0.757848646514436165305674088364798107415772156823526394781277032859370615544627343198300308302394419345163450113384406222231838091222846932198471177164033…
#imaginaryctf2021 n = 1871866865483941810106035041489767872458177408174210228790876521269086223189954740558299715702009349950617763239543057254260001925842494780359139592647224634741398653143717780175432460620024371083660969445388889466865…
#HackTM_CTF_2020_Finals RSA from Crypto.Util.number import getStrongPrime, inverse, bytes_to_long from flag import flag p = getStrongPrime(1024) q = getStrongPrime(1024) e = 65537 N = p * q phiN = (p - 1) * (q - 1) d = inverse(e, phiN) dp …
#hsctf8 from Crypto.Util.number import * import binascii flag = open('flag.txt','rb').read() p = getPrime(1024) q = getPrime(1024) n = p*q e = 2**16+1 pt = int(binascii.hexlify(flag).decode(),16) print(p>>512) print(q%(2**512)) print(n, e)…
#!/usr/bin/python from Crypto.Util.number import * from random import * from gmpy2 import * from fractions import * from binascii import hexlify from secret import flag #Setting up params a = randrange(2**10,2**11) b = randrange(2**12,2**1…
#FireshellCTF2019 https://ctftime.org/task/7486 問題文 If you know your keyboard, you know the flag 一緒に渡されるファイル https://gist.githubusercontent.com/theoldmoon0602/fcf5368212f584262ae730bb1b34cbc6/raw/f3fb787e62053a78178da51f8a2ad…
#diceCTF2022 from Crypto.Util.number import getPrime, bytes_to_long, long_to_bytes def getAnnoyingPrime(nbits, e): while True: p = getPrime(nbits) if (p-1) % e**2 == 0: return p nbits = 128 e = 17 p = getAnnoyingPrime(nbits, e) q = getAnno…
鍵長： 56bit（64bitの鍵を与えるが、その後8bit捨てられる） ブロック長： 64bit 16ラウンドのFeistel構造を用いたブロック暗号 DESは次のような疑似コードで表される def feistel(m, k): m = expand(m) # 32bit -> 48bit m = m ^ k return [sboxes[i](m[i*…
#cryptoctf2021 m = bytes_to_long(flag) e = 65537 n = p * q = 4024625003400831261259737276316748212140359464095903327962527444430093199954898873916032867176701877865239488518540105913088786921133059927211384908878012962458167444131493813926…
#cryptoctf2021
#CrewCTF_2022 from Crypto.Util.number import getPrime, bytes_to_long, inverse, isPrime from secret import flag m = bytes_to_long(flag) def getSpecialPrime(): a = 2 for i in range(40): a*=getPrime(20) while True: b = getPrime(20) if isPrime…
