add s-m-r-a

[wiki.git] / doc / root-instance.mdwn

diff --git a/doc/root-instance.mdwn b/doc/root-instance.mdwn
index 46666b15fe29ea57a71c0dc3c6603f13acf1353b..301ed226f9d8f9bb55d53671a65136b06f7ea9b7 100644 (file)
--- a/doc/root-instance.mdwn
+++ b/doc/root-instance.mdwn
@@ -100,9 +100,27 @@ extra instance's password instead.
 
 ## Getting them
 
-You need to show up in person to IS&T User Accounts in N42 with a
+You need to show up in person to [IS&T User
+Accounts](http://ist.mit.edu/support/accounts) in
+[E17](http://whereis.mit.edu/?go=E17) during business hours with a
 photo ID to obtain new Kerberos identities. For the reasons described
 above, being in control of your null instance and sending a zephyr or
 authenticated e-mail with it does not mean that you can go ahead and
 make changes to your root or extra instance too.  While you're there,
 be sure to ask for a pts id, if you want to use your tickets with AFS.
+
+## Upgrading cryptographic strength
+
+You should change your root instance’s password with a command like this, to upgrade your key from critically weak DES encryption algorithm to strong AES encryption:
+
+    kadmin -p andersk/root -q 'cpw -e aes256-cts:normal -e aes128-cts:normal andersk/root'
+
+(Note: This might make your password incompatible with a [handful of services](http://debathena.mit.edu/trac/ticket/529) that you should not have been using with your root instance in the first place.)  You can confirm the change with
+
+    kadmin -p andersk/root -q 'getprinc andersk/root'
+
+which should list a line like
+
+    Key: vno 4, aes256-cts-hmac-sha1-96, no salt
+
+If you change your password again, you will need to specify your desired enctypes with the -e option; otherwise, they will be reset to the defaults.