Fix xor

cw/cw.tex

@@ -53,8 +53,8 @@
 	if the message is only one block long:
 	$$H=E$$
 	$$m\ne m'$$
-	$$H(m)=E(K, IV \xor m) = C_1$$
-	$$H(m')=E(K, IV \xor m') = C_2$$
+	$$H(m)=E(K, IV \oplus m) = C_1$$
+	$$H(m')=E(K, IV \oplus m') = C_2$$
 	And if there the hashing function was not collision resistant that would imply
 	$$C_1=C_2\implies D(C_1)=D(C_2) \impies m=m'$$
 	and since $m !=m'$ the hash function is collision resistant, for messages with 1 block.