RSA with no padding

gistfile1.rb

# encoding: UTF-8

require 'ruby-debug'
require 'openssl'

def crypt(value, padding = OpenSSL::PKey::RSA::NO_PADDING)
  public_key = get_rsa_key 'public.pem'
  public_key.public_encrypt value, padding
end

def get_rsa_key(key, password = '')
  return key if key.is_a?(OpenSSL::PKey::RSA)

  key = File.read(key) if key !~ /^-+BEGIN .* KEY-+$/

  return OpenSSL::PKey::RSA.new(key, password)
end

crypt 'xpto' #=> OpenSSL::PKey::RSAError Exception: data too small for key size