So, You have 30-something multiuser accounts at Wesleyan and you are utterly sick of coming up with strange schemes to remember their almost infinite permutations and incrementations. (Is that a word?). Ssh to the rescue.

• 1. Learn about ssh. Here is in general how it works. (Really general). Like PGP it is a public key / private key system. Ssh uses DES, RSA, or Blowfish (default I think is RSA) encryption. These identities are in essence _really_ large, random scrambled prime numbers.
• 2. So, you need a public identity and a private identity. ssh provides both with the ssh-keygen program (found in /usr/local/bin). When run it will initialize its prime number generator (The coolest part about this is that you can look up their algorithm on the net at their page www.ssh.fi/ssh/). ssh will ask you for a pass-key which is then encrytped via RSA into your ~/.ssh/identity file (by default).
• 3. If you try to read your private key, you will screw up your terminal because it is a binary file. But, the private key is a text file containing the name of the identity and its public key. Thus, if you use this account on another machie, you should save your public identity file as ~/.ssh/authorized_keys on the other machine.
• 4. Now, on the machine you are at. Run something like this: ssh-agent tcsh. This runs the program ssh-agent as a wrapper around tcsh. As long as tcsh lives everything run under it will receive a couple of environment variables from ssh.
  This is also mighty useful for xdm sessions. When I log into xdm on my computer, my .xsession has a line in it which does this: /usr/local/bin/ssh-agent wmaker Thus, anything spawned by my window manager will receive the appropriate environment variables for ssh without me doing anything.
• 5. Finally, run ssh-add and supply your key-phrase. This is analagous to kinit in a kerberos domain. This will now make it possible to log into any machine on which you placed your identity.pub. In addition, there are a number of other things this helps with -- pine over IMAP without a password, scp without a password, and almost any other program you may wish to use.
• 6. Run ssh machinename. Enjoy. As they say, Enjoy life, Eat out often.

Personally, I set up many many aliases in my .tcshrc so that after all this is set up I do not have to type the ssh part as that is almost as many keys as my passwords were. :)

Here is a rundown of how it works using two machines, named client and serverlet.

client:~% ssh-keygen
Initializing random number generator...
Generating p:  ..................++ (distance 374)
Generating q:  .........++ (distance 104)
Computing the keys...
Testing the keys...
Key generation complete.
Enter file in which to save the key (/export/home/abelew/.ssh/identity): 
Enter passphrase: 
Enter the same passphrase again: 
Your identification has been saved in /export/home/abelew/.ssh/identity.
Your public key is:
1024 35 148729563822324045140159655782189629792176856344012351577477614949230750057706772
1230662387279363131008007828593150137060188822701494468854641083813050408288617658316617
8864825524929729260692629455742689729374893803997241158687884460310012377934472933930507
7078373215859157336562267177540885071818960835456417 abelew@client
Your public key has been saved in /export/home/abelew/.ssh/identity.pub

client:~% ssh abelew@serverlet mkdir ~/.ssh
Enter RSA passphrase for 'trey@client' :
Enter password for trey@serverlet :

client:~% scp ~/.ssh/identity.pub abelew@serverlet:~/.ssh/authorized_keys
Enter RSA passphrase for 'trey@client' :
Enter password for trey@serverlet :

client:~%  ssh-agent tcsh

client:~%  ssh-add
Need passphrase for /export/home/abelew/.ssh/identity (abelew@client).
Enter passphrase:

client:~%  echo "Woo Hoo!!!  It worked!"
Woo Hoo!!! It worked!

client:~% ssh abelew@student
You have mail.
  4:05pm  up 12 day(s),  4:32,  55 users,  load average: 0.57, 0.60, 0.56
serverlet:~%  pine

serverlet:~% exit

client:~%  cat .tcshrc
alias sea 'ssh abelew@search.wesleyan.edu'
alias bbs 'ssh bbs@bbs.con.wesleyan.edu'                         
alias veg 'ssh trey@veggie.wesleyan.edu'        
alias con 'ssh abelew@condor.wesleyan.edu'
alias thr 'ssh abelew@mail.wesleyan.edu'
alias bob 'ssh trey@bobwhite.con.wesleyan.edu'
alias www 'ssh abelew@www.wesleyan.edu'
alias hel 'ssh trey@helpdesk.wesleyan.edu'
alias cau 'ssh trey@caucus.cs.wesleyan.edu'
alias cla 'ssh trey@claude.math.wesleyan.edu'
alias met 'ssh trey@metonymy.cs.wesleyan.edu'
alias all 'ssh trey@allegory.cs.wesleyan.edu'
alias oly 'ssh trey@olympus.wesleyan.edu'
alias t-r 'ssh abelew@t-rex.wesleyan.edu'
alias pea 'ssh trey@peacock.con.wesleyan.edu'
alias auk 'ssh trey@auk.con.wesleyan.edu'
alias ori 'ssh trey@oriole.con.wesleyan.edu'
alias pic 'ssh abelew@picasso.cslab.wesleyan.edu'
alias new 'ssh abelew@news.wesleyan.edu'
alias ste 'ssh trey@sterling.phys.wesleyan.edu'
alias goo 'ssh trey@goose.con.wesleyan.edu'
alias reg 'ssh abelew@registration.wesleyan.edu'

client:~% 

To reiterate, this is potentially really useful to get around. On other use is to use this and then run pine on condor with no .pinerc in your home directory. You will notice that it immediately opens up your inbox on mail.wesleyan.edu without any password :)