show run
  Building configuration...

  !
  encryption key 1 size 40bit 7 621AA6093A25 transmit-key
  encryption key 2 size 40bit 7 7260637E4720
  encryption key 3 size 40bit 7 0F733F116035
  encryption key 4 size 40bit 7 03B71F3D601D
  encryption mode wep mandatory
  !

##</code><code>##

key : 1
size: 40       
value: 621AA6093A25  (the length could be different)
TransmitKey: true    

# The number 7 in the encryption key information should be ignored.

##</code><code>##

for ($Count=1; $Count<=4; $Count++)  {
  if ($showrunOutput=~/encryption\skey\s$Count\s(.+)\s\n/){
     print $1; 
  }
}