1 s='d4e8e1f4a0f7e1f3a0e6e1f3f4a1a0d4e8e5a0e6ece1e7a0e9f3baa0c4c4c3d4c6fbb9e1e6b3e3b9e4b3b7b7e2b6b1e4b2b6b9e2b1b1b3b3b7e6b3b3b0e3b9b3b5e6fd'
 2 '''
 3 s1=''
 4 for x in range(len(s)/2):
 5     s1+=chr((int(s[x*2:x*2+2],16))%128)
 6 print s1
 7 '''
 8
 9 for j in range(20):
10     s1=''
11     for x in range(len(s)/2):
12         s1+=chr((int(s[x*2:x*2+2],16)-j)%128)
13     print s1
14     

1 import collections
2
3 f=open('file.txt','r')
4 print collections.Counter(f.read())

 1 #!/usr/bin/env python
 2 import sys
 3 import json
 4 from Crypto.Cipher import AES
 5 from Crypto import Random
 6
 7
 8 def get_padding(rawstr):
 9     remainder = len(rawstr) % 16
10     if remainder != 0:
11         return '\x00' * (16 - remainder)
12     return ''
13
14
15 def aes_encrypt(key, plaintext):
16     plaintext += get_padding(plaintext)
17     aes = AES.new(key, AES.MODE_ECB)
18     cipher_text = aes.encrypt(plaintext).encode('hex')
19     return cipher_text
20
21
22 def generate_hello(key, name, flag):
23     message = "Connection for mission: {}, your mission's flag is: {}".format(name, flag)
24     return aes_encrypt(key, message)
25
26
27 def get_input():
28     return raw_input()
29
30
31 def print_output(message):
32     print(message)
33     sys.stdout.flush()
34
35
36 def handle():
37     print_output("Please enter mission key:")
38     mission_key = get_input().rstrip()
39
40     print_output("Please enter your Agent ID to secure communications:")
41     agentid = get_input().rstrip()
42     rnd = Random.new()
43     session_key = rnd.read(16)
44
45     flag = '<secret>'
46     print_output(generate_hello(session_key, agentid, flag))
47     while True:
48         print_output("Please send some messages to be encrypted, 'quit' to exit:")
49         msg = get_input().rstrip()
50         if msg == 'quit':
51             print_output("Bye!")
52             break
53         enc = aes_encrypt(session_key, msg)
54         print_output(enc)
55
56
57 if __name__ == "__main__":
58     handle()

 1 #coding=utf-8
 2 import socket
 3 import string
 4 mission_key = '''xxxxxxxxxxxxxxxxxxxxxxxxxxxxx'''
 5 a='''1234567890123456789012345678901234567890'''#最初的agent_id
 6 flag='DDCTF{'
 7 msg="flag is: DDCTF{"
 8 for x in range(1,33):#长度32位
 9     agent=a[:40-x]+'\n'#每次变换agent
10     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
11     s.connect(('116.85.48.103',5002))
12     s.recv(1024)
13     s.send(mission_key+'\n')
14     s.recv(1024)
15     s.send(agent)
16     c=s.recv(1024).rstrip()
17     for i in string.printable:
18         s.recv(1024)
19         s.send(msg+i+'\n')
20         ss=s.recv(1024).rstrip()[:32]
21         if(ss==c[160:192]):
22             msg=msg[1:]+i
23             flag+=i
24             print flag
25             break
26     s.close()
27 print flag+'}'

 1 from PIL import Image
 2 import cmath, math, random, string
 3
 4 maxLen = 45
 5 img_size = 800
 6 abs_cor_size = 1.05
 7 maxValue = 2200.0
 8
 9 def linear_map(v, old_dbound, old_ubound, new_dbound, new_ubound):
10     return (v-old_dbound)*1.0/(old_ubound-old_dbound)*(new_ubound-new_dbound) + new_dbound
11
12 def read_from_img(img):
13     def mapping(r, i):
14         x = int(round(linear_map(r, -abs_cor_size, abs_cor_size, 0, img_size)))
15         y = int(round(linear_map(i, -abs_cor_size, abs_cor_size, img_size, 0)))
16         return (x, y)
17     def X(z):
18         pix_pos = mapping(z.real, z.imag)
19         t = img.getpixel(pix_pos)
20         return complex(linear_map(t[1], 0, 255, -maxValue, maxValue), linear_map(t[2], 0, 255, -maxValue, maxValue))
21     return X
22
23 def z_decrypt(X):
24     real_max_val = 0.0
25     decrypted = []
26     for n in xrange(maxLen):
27         res = 0.0
28         dw = 0.001
29         w = -math.pi
30         while w < math.pi:
31             v = X(pow(math.e, 1j * w))
32             if v.real > real_max_val: real_max_val = v.real
33             if v.imag > real_max_val: real_max_val = v.imag
34             res += v * pow(math.e, 1j * w * n) * dw
35             w += dw
36         decrypted.append(res/math.pi/2)
37     print 'realmax', real_max_val
38     err = [math.fabs(j.imag) for j in decrypted]
39     res = ''.join([string.printable[j-1] if j <= len(string.printable) and j >= 1 else '?' for i in decrypted for j in [int(round(i.real))]]).strip('?')
40     return res
41
42 img = Image.open('encrypted.bmp')
43 X = read_from_img(img)
44 decrypted = z_decrypt(X)
45 print len(decrypted), decrypted
46 print '--------- decrypted! ----------------'