73 lines
1.8 KiB
Markdown
73 lines
1.8 KiB
Markdown
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## Difficulty
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50/100
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## Category
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Programming
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## How To Solve
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Each of the 'friends' will give you harder and harder mathematical
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puzzles to solve. Everytime you solve one you get to know a new friend.
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Their names are always the first letter of the flag and then something
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random. This is obvious because if you print them out the first couple
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of friends are called I, G, C, T, F which spells IGCTF. The flag is
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then the first names of all friends back to back `IGCTFBR0M4NCE`.
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To solve these math puzzles, you need to write a program because they
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have to be solved within 10 seconds. You can use a python module to do
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it afaik, but I wrote a dead simple script that uses eval and some
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string replacements.
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```python
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from pwn import *
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import time
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def sin(exp): return math.sin(math.radians(eval(str(exp))))
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def cos(exp): return math.cos(math.radians(eval(str(exp))))
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def sqrt(exp): return math.sqrt(eval(str(exp)))
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def solve(expression):
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newexpr = ''
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for i, c in enumerate(expression):
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if c == '|' and expression[i-5:].startswith('sqrt'):
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newexpr += "abs("
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elif c == '|':
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newexpr += ')'
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else:
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newexpr += c
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#print(newexpr)
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return str(eval(newexpr))
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conn = remote('localhost', 3005)
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#conn = process(['python3', './friend-generator.py'])
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time.sleep(0.1)
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print(conn.recv())
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conn.send('yes\n'.encode())
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time.sleep(0.1)
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names = []
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while True:
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data = conn.recv().decode()
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try:
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name = data[data.index('name'):].split('\n')[0][8:].split(',')[0]
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expression = data[data.index('first: '):].split('\n')[1]
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except ValueError:
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print(data)
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exit(0)
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solution = solve(expression)
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#print(f"= {solution}")
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print(name)
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names.append(name)
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conn.send((solution + "\n").encode())
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time.sleep(0.1)
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```
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## Hints
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n/a
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## Flag
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IGCTFBR0M4NCE
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