HP ProCurve Switch 6120G/XG Manual page 231

Note
When you generate a host key pair on the switch, the switch places the key
pair in flash memory (and not in the running-config file). Also, the switch
maintains the key pair across reboots, including power cycles. You should
consider this key pair to be "permanent"; that is, avoid re-generating the key
pair without a compelling reason. Otherwise, you will have to re-introduce the
switch's public key on all management stations you have set up for SSH access
to the switch using the earlier pair.
Removing (zeroing) the switch's public/private key pair renders the switch
unable to engage in SSH operation and automatically disables IP SSH on the
switch. (To verify whether SSH is enabled, execute show ip ssh.)However, any
active SSH sessions will continue to run, unless explicitly terminated with the
CLI 'kill' command.
To Generate or Erase the Switch's Public/Private Host Key Pair.
Because the host key pair is stored in flash instead of the running-config file,
it is not necessary to use write memory to save the key pair. Erasing the key
pair automatically disables SSH.
Syntax: crypto key generate <autorun-key [rsa] | cert [rsa] <keysize> | ssh [dsa |
rsa] bits <keysize>>
Installs authentication files for ssh or https server, or for
autorun.
autorun-key
Install RSA key for autorun. See "Configuring Autorun
on the Switch" in Appendix A of the Management and
Configuration Guide for more information.
cert
Install RSA key for https certificate. See "Configuring
the Switch for SSL Operation" on page 7-7 in this guide
for more information.
ssh [dsa | rsa]
Install host key for ssh server. Specify the key type as
DSA or RSA.
bits <keysize>
zeroize <ssh | cert | autorun [rsa]>
Erases the switch's public/private key pair and dis-
ables SSH operation.
Configuring the Switch for SSH Operation
Specify the key size (in bits). See Table 6-2.
Configuring Secure Shell (SSH)
6-11