module Net::SSH::Authentication::PubKeyFingerprint

def self.fingerprint(blob, algorithm = 'MD5')
  case algorithm.to_s.upcase
  when 'MD5'
    OpenSSL::Digest.hexdigest(algorithm, blob).scan(/../).join(":")
  when 'SHA256'
    "SHA256:#{[OpenSSL::Digest.digest(algorithm, blob)].pack('m').chomp.gsub(/=+\z/, '')}"
  else
    raise OpenSSL::Digest::DigestError, "unsupported ssh key digest #{algorithm}"
  end
end