**Diffie Hellman - Crypto - 225**

Enoncé :

```
Just find a and b

Note: Flag format will be YUBITSEC{a,b}

```

__Résolution :__

On a comme information sur l'image :
```
q=1357
g=10

g^a mod q = 419
g^b mod q = 34
g^ab mod q = 33

a < 1000
b < 1000
```
Avec Sagemath on résout l'équation :

```

sage: for a in range(1000):
....: if int(pow(g,a)%q)==419:
....: print "trouver :"+str(a)
....:
....:
trouver :521

sage: for b in range(1000):
....: if int(pow(g,b)%q)==34:
....: print "trouver :"+str(b)
....:
....:
....:
trouver :619
```

flag : YUBITSEC{521,619}

By team Beers4Flags

```
________
| |
| #BFF |
|________|
_.._,_|,_
( | )
]~,"-.-~~[
.=] Beers ([
| ]) 4 ([
'=]) Flags [
|:: ' |
~~----~~
```

Original writeup (https://github.com/Beers4Flags/writeups/tree/master/2017/yubitsec/crypto/diffie_hellman).