Hello Navi

#!/usr/bin/env python3
from itertools import cycle

# JPG file magic header
known_header = bytes.fromhex("FF D8 FF E0 00 10 4A 46 49 46 00 01")

# Read encrypted file
with open("my_magic_bytes.jpg.enc", "rb") as f:
    cipher_data = f.read()

# Extract encrypted header
cipher_header = cipher_data[:12]

# Recover XOR key: ciphertext XOR plaintext = key
key = bytes([c ^ p for c, p in zip(cipher_header, known_header)])
print(f"[*] Calculated Key: {key.hex().upper()}")

# Decrypt entire file by applying repeating key
decrypted_data = bytes([c ^ k for c, k in zip(cipher_data, cycle(key))])

# Save decrypted image
with open("flag.jpg", "wb") as f:
    f.write(decrypted_data)

print("[*] Decrypted! Check flag.jpg")

import binascii
import requests

BASE_URL = "https://2c5a74f7cc3f1fdf.247ctf.com"

def solve():
    # Block 1: First 16 bytes of target
    part1_plain = b"impossible_flag_"
    payload1 = binascii.hexlify(part1_plain).decode()
    r1 = requests.get(f"{BASE_URL}/encrypt?user={payload1}")
    cipher_part1 = r1.text[:32]  # 32 hex chars = 16 bytes
    print(f"[*] Block 1 Cipher: {cipher_part1}")

    # Block 2: Remaining 7 bytes + PKCS#7 padding to 16 bytes
    padding_len = 16 - (23 % 16) # target is 23 bytes, part 2 is 7 bytes. 16 - 7 = 9.
    part2_plain = b"user" + bytes([padding_len] * padding_len)
    payload2 = binascii.hexlify(part2_plain).decode()
    r2 = requests.get(f"{BASE_URL}/encrypt?user={payload2}")
    cipher_part2 = r2.text[:32]
    print(f"[*] Block 2 Cipher: {cipher_part2}")

    # Forge token by concatenating blocks
    final_token = cipher_part1 + cipher_part2
    print(f"[*] Forged Token: {final_token}")

    # Get flag
    r_flag = requests.get(f"{BASE_URL}/get_flag?user={final_token}")
    print(f"\n---> FLAG: {r_flag.text}")

if __name__ == "__main__":
    solve()

#!/usr/bin/env python3
import pwn

HOST = "7a3875d00fa5d462.247ctf.com"
PORT = 50337

pwn.context.log_level = "info"
pwn.tube.newline = b"\r\n"


def solve_challenge():
    conn = None
    try:
        conn = pwn.remote(HOST, PORT)

        for i in range(500):
            conn.recvuntil(b"answer to ")
            question_line = conn.recvline().decode().strip()
            expression = question_line.replace("?", "")
            result = int(eval(expression))
            conn.sendline(str(result).encode())
            pwn.log.info(f"Progress: [{i + 1}/500] Solved: {expression} = {result}")

        pwn.log.success("500 problems solved! Waiting for flag...")
        conn.interactive()

    except Exception as e:
        pwn.log.error(f"An error occurred: {e}")

    finally:
        if conn:
            pwn.log.info("Connection closed.")
            conn.close()


if __name__ == "__main__":
    solve_challenge()

#!/usr/bin/env python3
from scapy.all import rdpcap
from scapy.layers.inet import ICMP

packets = rdpcap("error_reporting.pcap")
flag = b""

for p in packets:
    # ICMP type 0 = Echo Reply (responses to ping requests)
    if p.haslayer(ICMP) and p[ICMP].type == 0 and p.haslayer("Raw"):
        flag += p["Raw"].load

with open("flag.jpg", "wb") as f:
    f.write(flag)

print("[+] Extracted data saved to flag.jpg")

#!/usr/bin/env python3
import glob
import os

from cryptography import x509
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives.asymmetric.rsa import RSAPrivateKey, RSAPublicKey
from scapy import dadict
from scapy.all import *
from scapy.all import Raw, load_layer, rdpcap
from scapy.layers.inet import IP, TCP
from scapy.layers.tls.all import TLS
from scapy.layers.tls.cert import Cert
from scapy.layers.tls.handshake import TLSCertificate

PCAP_FILE = "/home/kita/Downloads/multiplication_tables.pcap"
KEYS = "/home/kita/Downloads/keys/"

load_layer("tls")


def find_cert(pcap_path):
    packets = rdpcap(pcap_path)
    cert_list = []

    for pkt in packets:
        if pkt.haslayer(Raw):
            raw = pkt[Raw].load
            try:
                tls_parsed = TLS(raw)
                tls_cert_layer = tls_parsed.getlayer(TLSCertificate)
                if tls_cert_layer:
                    print("[-] Found TLS Certificate.")
                    cert = tls_cert_layer.certs
                    for _, x509_wrapper in cert:
                        cert_list.append(x509_wrapper)
                        print("[-] Extracted a TLS Certificate.")
                else:
                    print("[-] Found TLS packet.")
            except Exception as e:
                print(f"[-] Error: {e}")
                continue
    return cert_list


def find_matching_private_key(target_modulus: int, keys_directory: str) -> str | None:
    print(f"[*] Searching for matching private key in {keys_directory} ...")

    for key_file in glob(os.path.join(keys_directory, "*")):
        try:
            with open(key_file, "rb") as f:
                private_key = serialization.load_pem_private_key(
                    f.read(), password=None, backend=default_backend()
                )

            # 类型守卫
            if isinstance(private_key, rsa.RSAPrivateKey):
                priv_modulus = private_key.private_numbers().public_numbers.n
                if priv_modulus == target_modulus:
                    print(f"[!] BINGO! Matching key found: {key_file}")
                    return key_file
        except Exception:
            pass  # 静默忽略无法解析的非私钥文件

    print("[-] No matching key found.")
    return None


def get_modulus(cert_obj):
    assert isinstance(cert_obj, Cert)
    pubkey_bytes = cert_obj.pubKey.der

    try:
        public_key = serialization.load_der_public_key(pubkey_bytes)

        if not isinstance(public_key, rsa.RSAPublicKey):
            print("[-] Not an RSA public key.")
            return None

        # 3. 提取 Modulus (N)
        return public_key.public_numbers().n

    except ValueError as e:
        print(f"[-] Failed to parse public key: {e}")
        return None


def get_exponent(cert_obj):
    assert isinstance(cert_obj, Cert)
    pubkey_bytes = cert_obj.pubKey.der

    try:
        public_key = serialization.load_der_public_key(pubkey_bytes)

        if not isinstance(public_key, rsa.RSAPublicKey):
            print("[-] Not an RSA public key.")
            return None

        # 3. 提取 Exponent (e)
        return public_key.public_numbers().e

    except ValueError as e:
        print(f"[-] Failed to parse public key: {e}")
        return None


def check_pcap(pcap_path):
    packets = rdpcap(pcap_path)
    packets.show()
    for pkt in packets:
        pkt.show()
        if pkt.haslayer(Raw):
            raw = pkt[Raw].load
            try:
                print(raw.decode())
            except Exception as e:
                print(f"[-] Error: {e}")
                continue


if __name__ == "__main__":
    cert_list = find_cert(PCAP_FILE)
    print(cert_list)
    for cert_obj in cert_list:
        modulus = get_modulus(cert_obj)
        exponent = get_exponent(cert_obj)
        print(modulus)
        print(exponent)

    # if modulus:
    #     key_path = find_matching_private_key(modulus, KEYS)
    #     print(key_path)

#!/usr/bin/env python3
import json
import sys
import urllib.error
import urllib.request


def query_factordb(number: str):
    url = f"http://factordb.com/api?query={number}"
    headers = {"User-Agent": "ArchLinux-PowerUser/1.0"}

    try:
        req = urllib.request.Request(url, headers=headers)
        with urllib.request.urlopen(req) as response:
            data = json.loads(response.read().decode("utf-8"))

            status = data.get("status", "Unknown")
            factors = data.get("factors", [])

            print(f"[*] Target : {number}")
            print(f"[*] Status : {status}")

            if factors:
                result = " * ".join([f"{base}^{exp}" for base, exp in factors])
                print(f"[*] Factors: {result}")
            else:
                print("[!] No factors returned.")

    except urllib.error.URLError as e:
        print(f"[!] Network Error: {e.reason}")
    except ValueError:
        print("[!] JSON parsing failed. Did FactorDB change their API?")


if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: ./fdb.py <number>")
        sys.exit(1)

    query_factordb(sys.argv[1])

from Crypto.PublicKey import RSA

p = 11443069641880629381891581986018548808448150675612774441982091938562801238612124445967724562059877882869924090566492089872161438646198325341704520958011761
q = 13120664517031861557695339067275706831429518210212092859212127044658713747906482358428924486662467583986570766086011893335839637764790393666582606794678939
e = 65537

n = p * q
phi = (p - 1) * (q - 1)
d = pow(e, -1, phi)

key = RSA.construct((n, e, d, p, q))
with open("private_key.pem", "wb") as f:
    f.write(key.export_key())
print("Key forged successfully.")

import matplotlib.pyplot as plt

x_coords = []
y_coords = []

with open("secret_map.txt", "r") as f:
    for line in f:
        line = line.strip()
        if line:
            parts = line.split()
            x_coords.append(int(parts[0], 16))
            y_coords.append(-int(parts[1], 16))

plt.scatter(x_coords, y_coords, s=1, color="black")
plt.axis("equal")
plt.axis("off")
plt.show()