theor.: add stylistical fixes

tex/part-theoretical.tex

@@ -105,7 +105,7 @@ passwords~\cite{rockyou},~\cite{plaintextpasswds1},~\cite{plaintextpasswds2},~\c
 
 So while a service might not be storing passwords in \emph{plain text}, which
 is a good practice, using a hashing function not designed to protect passwords
-does not offer much additional protection in the case of weak passwords, which
+does not offer much additional protection in case of weak passwords, which
 happen to be the ones that are the most commonly used.
 
 It would seem only logical that a service that is not using cryptographic
@@ -251,13 +251,12 @@ creating strong passwords directly, most users first try a basic version and
 then keep tweaking characters until the password ends up fulfilling the minimum
 requirement.
 
-The \emph{problem} with it is that it has been shown, that people use similar
-patterns, i.e.\ starting with capital letters, putting a symbol last and a
-number in the last two positions. This is also known to people cracking the
-password hashes and they run their dictionary attacks using the common
-substitutions, such as ``\$'' for ``s'', ``E'' for ``3'', ``1'' for ``l'',
-``@'' for ``a''
-etc.~\cite{megatron},~\cite{hashcracking},~\cite{hashcracking2}.  It is safe to
+The \emph{problem} is that that people use similar patterns, i.e.\ starting
+with capital letters, putting a symbol last and a number in the last two
+positions. This is also known to people cracking the password hashes and they
+run their dictionary attacks using the common substitutions, such as ``\$'' for
+``s'', ``E'' for ``3'', ``1'' for ``l'', ``@'' for ``a''
+etc.~\cite{hashcracking},~\cite{hashcracking2},~\cite{megatron}. It is safe to
 expect that the password created in this manner will almost certainly be bad,
 and the only achievement was to frustrate the user in order to still arrive at
 a bad password.