fingerprint

#!/bin/bash

# Source: https://superuser.com/a/1030779

# standard sshd config path
SSHD_CONFIG=/etc/ssh/sshd_config

# helper functions
function tablize {
  awk '{printf("| %-7s | %-7s | %-47s |\n", $1, $2, $3)}'
}
LINE="+---------+---------+-------------------------------------------------+"

# header
echo $LINE
echo "Cipher" "Algo" "Fingerprint" | tablize
echo $LINE

# fingerprints
for host_key in $(awk '/^HostKey/ {sub(/^HostKey\s+/,"");print $0".pub"};' $SSHD_CONFIG); do
  cipher=$(echo $host_key | sed -r 's/^.*ssh_host_([^_]+)_key\.pub$/\1/'| tr '[a-z]' '[A-Z]')
  if [[ -f "$host_key" ]]; then
    md5=$(ssh-keygen -l -f $host_key | awk '{print $2}')
    sha256=$(awk '{print $2}' $host_key | base64 -d | sha256sum -b | awk '{print $1}' | xxd -r -p | base64)

    echo $cipher MD5 $md5 | tablize
    echo $cipher SHA-256 $sha256 | tablize
    echo $LINE
  fi
done