diff --git a/lib/win32/certstore.rb b/lib/win32/certstore.rb
index 328d071..d530851 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?(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 cb192fa..c4766f7 100644
--- a/lib/win32/certstore/store_base.rb
+++ b/lib/win32/certstore/store_base.rb
@@ -102,7 +102,7 @@ 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)
@@ -127,6 +127,12 @@ 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)
@@ -138,12 +144,6 @@ def get_cert_pem(thumbprint)
         get_data.stdout
       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")
diff --git a/spec/win32/unit/certstore_spec.rb b/spec/win32/unit/certstore_spec.rb
index ed533a8..8d6d8d0 100644
--- a/spec/win32/unit/certstore_spec.rb
+++ b/spec/win32/unit/certstore_spec.rb
@@ -128,7 +128,7 @@
       let (:store_name) { "root" }
       let (:thumbprint) { "b1bc968bd4f49d622aa89a81f2150152a41d829c" }
       before(:each) do
-        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return([])
+        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return("")
       end
       it "returns nil" do
         store = certstore.open(store_name)
@@ -142,7 +142,7 @@
       let (:thumbprint) { "b1bc968bd4f49d622aa89a81f2150152a41d829909c" }
       let (:cert_pem) { File.read('.\spec\win32\unit\assets\GlobalSignRootCA.pem') }
       before(:each) do
-        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return([cert_pem])
+        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return(cert_pem)
       end
       it "returns OpenSSL::X509::Certificate Object" do
         store = certstore.open(store_name)
@@ -158,7 +158,7 @@
       let (:thumbprint) { "b1 bc 96 8b d4 f4 9d 62 2a a8 9a 81 f2 15 01 52 a4 1d 82 9c" }
       let (:cert_pem) { File.read('.\spec\win32\unit\assets\GlobalSignRootCA.pem') }
       before(:each) do
-        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return([cert_pem])
+        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return(cert_pem)
       end
       it "returns OpenSSL::X509::Certificate Object" do
         store = certstore.open(store_name)
@@ -174,7 +174,7 @@
       let (:thumbprint) { "b1:bc:96:8b:d4:f4:9d:62:2a:a8:9a:81:f2:15:01:52:a4:1d:82:9c" }
       let (:cert_pem) { File.read('.\spec\win32\unit\assets\GlobalSignRootCA.pem') }
       before(:each) do
-        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return([cert_pem])
+        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return(cert_pem)
       end
       it "returns OpenSSL::X509::Certificate Object" do
         store = certstore.open(store_name)
@@ -186,7 +186,7 @@
     end
   end
 
-  describe "#cert_verify" do
+  describe "#cert_validate" do
     context "When passing empty certificate store name" do
       let (:store_name) { "" }
       it "raises ArgumentError" do
@@ -199,7 +199,7 @@
       let (:thumbprint) { " " }
       it "raises ArgumentError" do
         store = certstore.open(store_name)
-        expect { store.verify(thumbprint) }.to raise_error(ArgumentError, "Invalid certificate thumbprint.")
+        expect { store.valid_certificate?(thumbprint) }.to raise_error(ArgumentError, "Invalid certificate thumbprint.")
       end
     end
 
@@ -208,7 +208,7 @@
       let (:thumbprint) { nil }
       it "raises ArgumentError" do
         store = certstore.open(store_name)
-        expect { store.verify(thumbprint) }.to raise_error(ArgumentError, "Invalid certificate thumbprint.")
+        expect { store.valid_certificate?(thumbprint) }.to raise_error(ArgumentError, "Invalid certificate thumbprint.")
       end
     end
 
@@ -216,54 +216,50 @@
       let (:store_name) { "root" }
       let (:thumbprint) { "b1bc968bd4f49d622aa89a81f2150152a41d829c" }
       before(:each) do
-        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return([])
+        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return("")
       end
       it "returns Certificate not found" do
         store = certstore.open(store_name)
-        cert_obj = store.verify(thumbprint)
-        expect(cert_obj).to eql("Certificate not found")
+        expect(store.valid_certificate?(thumbprint)).to eql("Certificate not found")
       end
     end
 
-    context "When passing valid thumbprint" do
+    context "When passing valid certificate's thumbprint" do
       let (:store_name) { "root" }
       let (:thumbprint) { "b1bc968bd4f49d622aa89a81f2150152a41d829909c" }
       let (:cert_pem) { File.read('.\spec\win32\unit\assets\GlobalSignRootCA.pem') }
       before(:each) do
-        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return([cert_pem])
+        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return(cert_pem)
       end
-      it "returns OpenSSL::X509::Certificate Object" do
+      it "returns true" do
         store = certstore.open(store_name)
-        cert_obj = store.verify(thumbprint)
-        expect(cert_obj).to eql(true)
+        expect(store.valid_certificate?(thumbprint)).to eql(true)
       end
     end
 
-    context "When passing valid thumbprint with spaces" do
+    context "When passing valid certificate's thumbprint with spaces" do
       let (:store_name) { "root" }
       let (:thumbprint) { "b1 bc 96 8b d4 f4 9d 62 2a a8 9a 81 f2 15 01 52 a4 1d 82 9c" }
       let (:cert_pem) { File.read('.\spec\win32\unit\assets\GlobalSignRootCA.pem') }
       before(:each) do
-        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return([cert_pem])
+        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return(cert_pem)
       end
-      it "returns OpenSSL::X509::Certificate Object" do
+      it "returns true" do
         store = certstore.open(store_name)
-        cert_obj = store.verify(thumbprint)
-        expect(cert_obj).to eql(true)
+        expect(store.valid_certificate?(thumbprint)).to eql(true)
       end
     end
 
-    context "When passing valid thumbprint with :" do
+    context "When passing valid certificate's thumbprint with :" do
       let (:store_name) { "root" }
       let (:thumbprint) { "b1:bc:96:8b:d4:f4:9d:62:2a:a8:9a:81:f2:15:01:52:a4:1d:82:9c" }
       let (:cert_pem) { File.read('.\spec\win32\unit\assets\GlobalSignRootCA.pem') }
       before(:each) do
-        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return([cert_pem])
+        allow_any_instance_of(certbase).to receive(:get_cert_pem).and_return(cert_pem)
       end
-      it "returns OpenSSL::X509::Certificate Object" do
+      it "returns true" do
         store = certstore.open(store_name)
-        cert_obj = store.verify(thumbprint)
-        expect(cert_obj).to eql(true)
+        expect(store.valid_certificate?(thumbprint)).to eql(true)
       end
     end
   end