第四届江西省高校网络安全技能大赛密码学题目收录

pukr

Yusa的日常生活—美国大选

1. from Crypto.Util.number import *
   
2. from secret import p,q
   
3. def gcd(a, b):
   
4.     while b:
   
5.         a, b = b, a%b
   
6.     return a
   
7.    
   
8. flag='DASCTF{********************************}'
   
9. e=3
   
10. phi = (p-1)*(q-1)
    
11. assert gcd(e,phi)==1
    
12. 
    
13. d = inverse(e,phi)
    
14. print r"Form of vote:{voter}:{votee}! eg: "
    
15. print "Yusa:Trump!"
    
16. vote = pow(bytes_to_long("Yusa:Trump!"),d,p*q)
    
17. print "vote:",vote
    
18. try:
    
19.     yusa = int(raw_input("Your vote: "))
    
20.     vote = long_to_bytes(pow(yusa,e,p*q)).split(":")
    
21.     print vote
    
22.     if vote[-1] == "Trump!":
    
23.         print flag[:10]
    
24.     elif vote[-1] == "Biden!":
    
25.         print flag[10:]
    
26. except Exception as e:
    
27.     print str(e)
    
28.     exit()

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pukr

第一题wp：
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poc

1. import gmpy2
   
2. from Crypto.Util.number import *
   
3. 
   
4. n = 2**56
   
5. phi = 2**55
   
6. e=3
   
7. m = bytes_to_long(b":Biden!")
   
8. 
   
9. d = gmpy2.inverse(e,phi)
   
10. c = pow(m,d,n)
    
11. print(c)

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