diff --git a/lib/mpw/config.rb b/lib/mpw/config.rb
index b504c2a..148ecf1 100644
--- a/lib/mpw/config.rb
+++ b/lib/mpw/config.rb
@@ -88,9 +88,9 @@ class Config
 	#        expire -> the time of expire to GPG key
 	# @rtrn: true if the GPG key is create, else false
 	def setup_gpg_key(password, name, length = 4096, expire = 0)
-		if name.nil? or name.empty?
+		if name.to_s.empty?
 			raise "#{I18n.t('error.config.genkey_gpg.name')}"
-		elsif password.nil? or password.empty?
+		elsif password.to_s.empty?
 			raise "#{I18n.t('error.config.genkey_gpg.password')}"
 		end