Fixed a couple of typos.

www/security.html

@@ -18,7 +18,7 @@ be aware of.
 
 <p>
 To enhance operation and security, we make use of a "Cookie" that
-holds your login name. Therefor, you will need to enable cookies on
+holds your login name. Therefore, you will need to enable cookies on
 your browser. Please contact us if you have questions about how to do
 that in your browser.
 </p>
@@ -77,7 +77,7 @@ which we will pass on to you at no extra charge:
 <h3>Email Addresses</h3>
 
 <p>
-We require all Emulab users to provided current, non-pseudonymic email
+We require all Emulab users to provide current, non-pseudonymic email
 addresses. Redirections and anonymous email addresses are not allowed.
 </p>
 
@@ -86,7 +86,7 @@ addresses. Redirections and anonymous email addresses are not allowed.
 <p>
 We employ a password checking library to prevent users from choosing
 passwords that could be guessed by the "Crack" library. A few basic
-rules are that standard english dictionary words are not permitted, as
+rules are that standard English dictionary words are not permitted, as
 well as anything deemed too short or easily guessable. Also, you
 should take care not to use the same password on Emulab that you use
 at other sites.
@@ -113,7 +113,7 @@ experimental net.
 <h3>Accounts</h3>
 
 <p>
-We make use of Unix user and group mechansisms to provide protection
+We make use of Unix user and group mechanisms to provide protection
 between users and projects. Each new user gets a new Unix UID, and
 each new project gets a new Unix GID. Users are members of the Unix
 groups that correspond to each of the projects they are working on,