Diffie-Hellman II======**Category: Steganography****Points: 275**
`II. part is STEGO.If you already solved the I. part.Everything is clear.Just analyze the file.`
This part is a continuation of Diffie Hellman I. The first part was basic bruteforce.
Here's the script for that:
```pythong = 10q = 1357for i in range(1000):	for j in range(1000):		if pow(g,i,q)==419 and pow(g,j,q)==34 and pow(g,i*j,q)==33:			print "a:"+str(i)+" b:"+str(j)```
`a:521 b:619`
As the second part was stego, I decided to run `strings` on the image file. 
At the bottom, there was a clue: `Hmm.. maybe the other part is stego``Key: abababababab`
Since they gave a key, I was pretty sure that I had to use steghide with the given key. 
So I replaced the **a**s with 521 and **b**s with 619 in the key and tried it as the password. And it worked!
I got a text file with a tumblr link: `http://ababababababqbababababababab.tumblr.com/`
On opening that link, we were asked for a password. On looking at the url, we saw that it was a different sequence of **a**,**b** and **q**. So I substituted the corresponding values in the url, and used it as a password. That was it, I was given the flag!
```Congratulations!
Here is the flag: YUBITSEC{Y0U_MUST_B3_1ZZ3TT1N}```
 
