diff --git a/lib/win32/certstore.rb b/lib/win32/certstore.rb
index 328d071..06c2658 100644
--- a/lib/win32/certstore.rb
+++ b/lib/win32/certstore.rb
@@ -71,8 +71,8 @@ def search(certificate_name)
     end
 
     # Validate certificate from open certificate store and return boolean
-    def verify(certificate_name)
-      cert_verify(certstore_handler, certificate_name)
+    def valid?(certificate_thumbprint)
+      cert_validate(certificate_thumbprint)
     end
 
     # To close and destroy pointer of open certificate store handler
diff --git a/lib/win32/certstore/mixin/helper.rb b/lib/win32/certstore/mixin/helper.rb
index f2b0671..1bdac82 100644
--- a/lib/win32/certstore/mixin/helper.rb
+++ b/lib/win32/certstore/mixin/helper.rb
@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+require 'date'
+
 module Win32
   class Certstore
     module Mixin
@@ -38,11 +40,11 @@ def cert_ps_cmd(thumbprint)
         end
 
         # validate certificate not_before and not_after date in UTC
-        def valid_duration(cert_obj)
+        def valid_duration?(cert_obj)
           cert_obj.not_before < Time.now.utc && cert_obj.not_after > Time.now.utc
         end
+
       end
     end
   end
 end
-
diff --git a/lib/win32/certstore/store_base.rb b/lib/win32/certstore/store_base.rb
index 7dc9936..f5b2272 100644
--- a/lib/win32/certstore/store_base.rb
+++ b/lib/win32/certstore/store_base.rb
@@ -105,7 +105,7 @@ def cert_delete(store_handler, certificate_thumbprint)
       # Verify certificate from open certificate store and return boolean or exceptions
       # store_handler => Open certificate store handler
       # certificate_thumbprint => thumbprint is a hash. which could be sha1 or md5.
-      def cert_verify(store_handler, certificate_thumbprint)
+      def cert_validate(certificate_thumbprint)
         validate_thumbprint(certificate_thumbprint)
         thumbprint = update_thumbprint(certificate_thumbprint)
         cert_pem = get_cert_pem(thumbprint)
@@ -135,6 +135,12 @@ def update_thumbprint(certificate_thumbprint)
         certificate_thumbprint.gsub(/[^A-Za-z0-9]/, '')
       end
 
+      # Verify OpenSSL::X509::Certificate object
+      def verify_certificate(cert_pem)
+        return "Certificate not found" if cert_pem.empty?
+        valid_duration?(build_openssl_obj(cert_pem))
+      end
+
       # Convert OpenSSL::X509::Certificate object in .der formate
       def der_cert(cert_obj)
         FFI::MemoryPointer.from_string(cert_obj.to_der)
@@ -151,12 +157,6 @@ def get_rdn(cert_obj)
         cert_obj.issuer.to_s.concat("/").scan(/=(.*?)\//).join(", ")
       end
 
-      # Verify OpenSSL::X509::Certificate object
-      def verify_certificate(cert_pem)
-        return "Certificate not found" if cert_pem.empty?
-        valid_duration(build_openssl_obj(cert_pem))
-      end
-
       # Format pem
       def format_pem(cert_pem)
         cert_pem.delete("\r")