diff --git a/lib/api_auth/headers.rb b/lib/api_auth/headers.rb
index 5ec0d42e..6504708b 100644
--- a/lib/api_auth/headers.rb
+++ b/lib/api_auth/headers.rb
@@ -67,15 +67,15 @@ def authorization_header
     end
 
     def set_date
-      @request.set_date if @request.timestamp.empty?
+      @request.set_date if @request.timestamp.nil?
     end
 
     def calculate_md5
-      @request.populate_content_md5 if @request.content_md5.empty?
+      @request.populate_content_md5 if @request.content_md5.nil?
     end
 
     def md5_mismatch?
-      if @request.content_md5.empty?
+      if @request.content_md5.nil?
         false
       else
         @request.md5_mismatch?
diff --git a/lib/api_auth/request_drivers/action_controller.rb b/lib/api_auth/request_drivers/action_controller.rb
index 458c7372..62563ea9 100644
--- a/lib/api_auth/request_drivers/action_controller.rb
+++ b/lib/api_auth/request_drivers/action_controller.rb
@@ -43,13 +43,11 @@ def http_method
       end
 
       def content_type
-        value = find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
       end
 
       def content_md5
-        value = find_header(%w[CONTENT-MD5 CONTENT_MD5 HTTP_CONTENT_MD5])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-MD5 CONTENT_MD5 HTTP_CONTENT_MD5])
       end
 
       def original_uri
@@ -66,8 +64,7 @@ def set_date
       end
 
       def timestamp
-        value = find_header(%w[DATE HTTP_DATE])
-        value.nil? ? '' : value
+        find_header(%w[DATE HTTP_DATE])
       end
 
       def authorization_header
diff --git a/lib/api_auth/request_drivers/curb.rb b/lib/api_auth/request_drivers/curb.rb
index 2be6c100..af049eae 100644
--- a/lib/api_auth/request_drivers/curb.rb
+++ b/lib/api_auth/request_drivers/curb.rb
@@ -32,13 +32,11 @@ def http_method
       end
 
       def content_type
-        value = find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
       end
 
       def content_md5
-        value = find_header(%w[CONTENT-MD5 CONTENT_MD5])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-MD5 CONTENT_MD5])
       end
 
       def original_uri
@@ -55,8 +53,7 @@ def set_date
       end
 
       def timestamp
-        value = find_header(%w[DATE HTTP_DATE])
-        value.nil? ? '' : value
+        find_header(%w[DATE HTTP_DATE])
       end
 
       def authorization_header
diff --git a/lib/api_auth/request_drivers/faraday.rb b/lib/api_auth/request_drivers/faraday.rb
index dc6960a9..d4cb9077 100644
--- a/lib/api_auth/request_drivers/faraday.rb
+++ b/lib/api_auth/request_drivers/faraday.rb
@@ -43,13 +43,11 @@ def http_method
       end
 
       def content_type
-        value = find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
       end
 
       def content_md5
-        value = find_header(%w[CONTENT-MD5 CONTENT_MD5 HTTP-CONTENT-MD5 HTTP_CONTENT_MD5])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-MD5 CONTENT_MD5 HTTP-CONTENT-MD5 HTTP_CONTENT_MD5])
       end
 
       def original_uri
@@ -69,8 +67,7 @@ def set_date
       end
 
       def timestamp
-        value = find_header(%w[DATE HTTP_DATE])
-        value.nil? ? '' : value
+        find_header(%w[DATE HTTP_DATE])
       end
 
       def authorization_header
diff --git a/lib/api_auth/request_drivers/httpi.rb b/lib/api_auth/request_drivers/httpi.rb
index 1ffcfc91..4543cc2e 100644
--- a/lib/api_auth/request_drivers/httpi.rb
+++ b/lib/api_auth/request_drivers/httpi.rb
@@ -42,13 +42,11 @@ def http_method
       end
 
       def content_type
-        value = find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
       end
 
       def content_md5
-        value = find_header(%w[CONTENT-MD5 CONTENT_MD5])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-MD5 CONTENT_MD5])
       end
 
       def original_uri
@@ -65,8 +63,7 @@ def set_date
       end
 
       def timestamp
-        value = find_header(%w[DATE HTTP_DATE])
-        value.nil? ? '' : value
+        find_header(%w[DATE HTTP_DATE])
       end
 
       def authorization_header
diff --git a/lib/api_auth/request_drivers/net_http.rb b/lib/api_auth/request_drivers/net_http.rb
index 4d301bfa..4b5d3865 100644
--- a/lib/api_auth/request_drivers/net_http.rb
+++ b/lib/api_auth/request_drivers/net_http.rb
@@ -49,13 +49,11 @@ def http_method
       end
 
       def content_type
-        value = find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
       end
 
       def content_md5
-        value = find_header(%w[CONTENT-MD5 CONTENT_MD5])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-MD5 CONTENT_MD5])
       end
 
       def original_uri
@@ -71,8 +69,7 @@ def set_date
       end
 
       def timestamp
-        value = find_header(%w[DATE HTTP_DATE])
-        value.nil? ? '' : value
+        find_header(%w[DATE HTTP_DATE])
       end
 
       def authorization_header
diff --git a/lib/api_auth/request_drivers/rack.rb b/lib/api_auth/request_drivers/rack.rb
index c31f98a7..2ee4554a 100644
--- a/lib/api_auth/request_drivers/rack.rb
+++ b/lib/api_auth/request_drivers/rack.rb
@@ -48,13 +48,11 @@ def http_method
       end
 
       def content_type
-        value = find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
       end
 
       def content_md5
-        value = find_header(%w[CONTENT-MD5 CONTENT_MD5 HTTP-CONTENT-MD5 HTTP_CONTENT_MD5])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-MD5 CONTENT_MD5 HTTP-CONTENT-MD5 HTTP_CONTENT_MD5])
       end
 
       def original_uri
@@ -71,8 +69,7 @@ def set_date
       end
 
       def timestamp
-        value = find_header(%w[DATE HTTP_DATE])
-        value.nil? ? '' : value
+        find_header(%w[DATE HTTP_DATE])
       end
 
       def authorization_header
diff --git a/lib/api_auth/request_drivers/rest_client.rb b/lib/api_auth/request_drivers/rest_client.rb
index 977a437c..cf7870d4 100644
--- a/lib/api_auth/request_drivers/rest_client.rb
+++ b/lib/api_auth/request_drivers/rest_client.rb
@@ -51,13 +51,11 @@ def http_method
       end
 
       def content_type
-        value = find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-TYPE CONTENT_TYPE HTTP_CONTENT_TYPE])
       end
 
       def content_md5
-        value = find_header(%w[CONTENT-MD5 CONTENT_MD5])
-        value.nil? ? '' : value
+        find_header(%w[CONTENT-MD5 CONTENT_MD5])
       end
 
       def original_uri
@@ -74,8 +72,7 @@ def set_date
       end
 
       def timestamp
-        value = find_header(%w[DATE HTTP_DATE])
-        value.nil? ? '' : value
+        find_header(%w[DATE HTTP_DATE])
       end
 
       def authorization_header
diff --git a/spec/headers_spec.rb b/spec/headers_spec.rb
index c352f253..4fbc50b4 100644
--- a/spec/headers_spec.rb
+++ b/spec/headers_spec.rb
@@ -188,14 +188,14 @@
 
     context 'when request has no md5' do
       it "doesn't ask the driver" do
-        allow(driver).to receive(:content_md5).and_return ''
+        allow(driver).to receive(:content_md5).and_return nil
 
         expect(driver).not_to receive(:md5_mismatch?).and_call_original
         headers.md5_mismatch?
       end
 
       it 'returns false' do
-        allow(driver).to receive(:content_md5).and_return ''
+        allow(driver).to receive(:content_md5).and_return nil
 
         expect(headers.md5_mismatch?).to be false
       end