diff --git a/cw/cw.tex b/cw/cw.tex
index 29f51d4..e3b5338 100644
--- a/cw/cw.tex
+++ b/cw/cw.tex
@@ -102,6 +102,20 @@
 	When the message has the size of a block, the authenticated encryption system scheme has both data confidentiality and integrity because the hash function is only collision resistant with messages of block size 1, because of that is impossible to change the ciphertext in away that when the mac is generated on the receiver side, the mac will be the same and since the mac key is not public the attacker cannot generate the new mac.
 	When the message has a bigger size than one block, the scheme still has data confidentiality because the message can still not be decrypted without knowing the key, but it has no longer data integrity because the attacker can change the message in such a way that it would generate a hash collision; therefore the sender could not prove that the information that was received was not sent that way by the server.
 
+	\section*{7}
+	\subsection*{7.1}
+	$$v1 = (137, 312), v2 = (215, −187)$$
+	$$mat =   \begin{pmatrix}
+			137 & 312 \\
+			215 & -187 \\
+			\end{pmatrix}$$
+	$$det(L)=|det(mat)|=|-92699|=92699$$
+
+	$$\H(\B)=(\frac{det(L)}{\|v1\|\times\|v2\|})\times\frac{1}{n}=(\frac{92699}{\sqrt{v1_1^2 + v1_2^2}\times\sqrt{v2_1^2 + v2_2^2}})\times\frac{1}{2}=$$
+	$$=\frac{92699}{2\times\sqrt{9427678922}}\approx0.477356$$
+
+	$det()$
+