diff --git a/lib/api_auth/headers.rb b/lib/api_auth/headers.rb
index bb0f4c6c..b8c04a6c 100644
--- a/lib/api_auth/headers.rb
+++ b/lib/api_auth/headers.rb
@@ -94,9 +94,31 @@ def sign_header(header)
     def parse_uri(uri)
       parsed_uri = URI.parse(uri)
 
-      return parsed_uri.request_uri if parsed_uri.respond_to?(:request_uri)
+      uri_without_host = parsed_uri.respond_to?(:request_uri) ? parsed_uri.request_uri : uri
+      return '/' if uri_without_host.empty?
+      escape_params(uri_without_host)
+    end
 
-      uri.empty? ? '/' : uri
+    # Different versions of request parsers escape/unescape the param values
+    # Examples:
+    # Rails 5.1.3 ApiAuth canonical_string:
+    #    'GET,application/json,,/api/v1/employees?select=epulse_id%2Cfirst_name%2Clast_name,Thu, 14 Dec 2017 16:19:48 GMT'
+    # Rails 5.1.4 ApiAuth canonical_string:
+    #    'GET,application/json,,/api/v1/employees?select=epulse_id,first_name,last_name,Thu, 14 Dec 2017 16:20:57 GMT'
+    # This will force param values to escaped and fixes issue #123
+    def escape_params(uri)
+      unescaped_uri = CGI.unescape(uri)
+      uri_array = unescaped_uri.split('?')
+      return uri unless uri_array.length > 1
+      params = uri_array[1].split('&')
+      encoded_params = ''
+      params.each do |param|
+        next unless param.include?('=')
+        encoded_params += '&' unless encoded_params.empty?
+        split_param = param.split('=')
+        encoded_params += split_param[0] + '=' + CGI.escape(split_param[1])
+      end
+      uri_array[0] + '?' + encoded_params
     end
   end
 end
diff --git a/spec/headers_spec.rb b/spec/headers_spec.rb
index fe31b794..36dea91d 100644
--- a/spec/headers_spec.rb
+++ b/spec/headers_spec.rb
@@ -35,13 +35,39 @@
         let(:uri) { 'http://google.com/?redirect_to=https://www.example.com'.freeze }
 
         it 'return /?redirect_to=https://www.example.com as canonical string path' do
-          expect(subject.canonical_string).to eq('GET,,,/?redirect_to=https://www.example.com,')
+          expect(subject.canonical_string).to eq('GET,,,/?redirect_to=https%3A%2F%2Fwww.example.com,')
         end
 
         it 'does not change request url (by removing host)' do
           expect(request.url).to eq(uri)
         end
       end
+
+      if RUBY_VERSION.to_f > 2.1
+        context 'uri param values are not escaped' do
+          let(:uri) do
+            'http://www.google.com/search/advanced?redirect_to=https://www.example.com&account=a12dd334/3444\:23'.freeze
+          end
+
+          it 'returns correct anonical string' do
+            expect(subject.canonical_string).to(
+              eq('GET,,,/search/advanced?redirect_to=https%3A%2F%2Fwww.example.com&account=a12dd334%2F3444%5C%3A23,')
+            )
+          end
+        end
+      end
+
+      context 'uri param values are escaped' do
+        let(:uri) do
+          'http://www.google.com/search/advanced?redirect_to=https%3A%2F%2Fwww.example.com&account=a12dd334%2F3444%5C%3A23'.freeze
+        end
+
+        it 'returns correct anonical string' do
+          expect(subject.canonical_string).to(
+            eq('GET,,,/search/advanced?redirect_to=https%3A%2F%2Fwww.example.com&account=a12dd334%2F3444%5C%3A23,')
+          )
+        end
+      end
     end
 
     context 'string construction' do