Generating SSH1 Key Pairs

Key generation for SSH1 begins in much the same way:

mbland@defender
/home/student/mbland -> ssh-keygen1
Initializing random number generator...
Generating p:  ..........++ (distance 102)
Generating q:  ............++ (distance 150)
Computing the keys...
Testing the keys...
Key generation complete.
Enter file in which to save the key (/home/student/mbland/.ssh/identity):
Enter passphrase:
Enter the same passphrase again:
Your identification has been saved in /home/student/mbland/.ssh/identity.
Your public key is:
1024 35 1242644011468066306624959825222292553266583039072289321333183076450939
803185937165302584768794486290682344210796792081448431964452132612759705157459
590401969775484674506955300214909857435651243966626794426301033400283753959104
523579590751005152438335881975736554762778872247864096463529626592511666622881
85517 mbland@defender
Your public key has been saved in /home/student/mbland/.ssh/identity.pub

Now ``chmod 700 .ssh && cd .ssh'' and take a look around:

mbland@defender
/home/student/mbland/.ssh -> ls -l
total 6
-rw-------  1 mbland  student   529 Apr 30 18:38 identity
-rw-------  1 mbland  student   333 Apr 30 18:38 identity.pub
-rw-------  1 mbland  student   512 Apr 30 18:38 random_seed

Again, if the file permissions in your directory don't look like this, chmod them until they do. Here's a breakdown of the contents of this directory:

• identity
  The private key generated by ssh-keygen1. Do not upload this key to other machines.

• identity.pub
  The public key generated by ssh-keygen1. Upload this key (using scp or sftp) into the ~/.ssh directory of each remote host to which you wish to connect.

• random_seed
  Used to generate the random numbers used as part of the SSH process. You should never need to open or otherwise modify this file.

Though, like SSH2, these names aren't terribly interesting either, you shouldn't rename ``identity'' at all. But go ahead and rename ``identity.pub'' to `` <localhost>.pub'' (i.e. ``defender.pub'') to ease the management of public keys between hosts.

You need to create an ``authorized_keys'' file by issuing a ``cp localhost.pub authorized_keys''. Then, after you've executed ssh-keygen1 on all the other hosts to which you wish to connect, you can update each host's authorized_keysfile by carrying out the following steps:

scp defender.pub <remotehost>:.ssh/
ssh1 <remotehost>
cd .ssh
cat >> authorized_keys < defender.pub

Again, you may be prompted for your password a couple of times, and you might prefer to update your authorized_keys file by hand, though the cat trick in this case might prove much more convenient. As opposed to SSH2, SSH1 keeps all its public keys together in a single file, rather than keeping a database of filenames corresponding to public keys.