diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 4e995552..b4c944dd 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,12 +1,12 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2017-04-30 12:02:22 -0400 using RuboCop version 0.35.0.
+# on 2017-09-13 09:10:02 +0200 using RuboCop version 0.35.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 3
+# Offense count: 4
 Lint/HandleExceptions:
   Exclude:
     - 'lib/slack-ruby-client.rb'
@@ -20,7 +20,7 @@ Lint/UnusedBlockArgument:
   Exclude:
     - 'lib/slack/messages/formatting.rb'
 
-# Offense count: 14
+# Offense count: 15
 Metrics/AbcSize:
   Max: 44
 
@@ -29,25 +29,25 @@ Metrics/AbcSize:
 Metrics/ClassLength:
   Max: 165
 
-# Offense count: 3
+# Offense count: 4
 Metrics/CyclomaticComplexity:
   Max: 9
 
-# Offense count: 720
+# Offense count: 615
 # Configuration parameters: AllowURI, URISchemes.
 Metrics/LineLength:
-  Max: 288
+  Max: 266
 
 # Offense count: 7
 # Configuration parameters: CountComments.
 Metrics/MethodLength:
   Max: 32
 
-# Offense count: 2
+# Offense count: 3
 Metrics/PerceivedComplexity:
   Max: 11
 
-# Offense count: 59
+# Offense count: 63
 # Configuration parameters: Exclude.
 Style/Documentation:
   Enabled: false
@@ -58,12 +58,12 @@ Style/FileName:
   Exclude:
     - 'lib/slack-ruby-client.rb'
 
-# Offense count: 116
+# Offense count: 120
 # Configuration parameters: AllowedVariables.
 Style/GlobalVars:
   Enabled: false
 
-# Offense count: 21
+# Offense count: 22
 # Configuration parameters: EnforcedStyle, SupportedStyles.
 Style/MethodName:
   Enabled: false
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 594e39fb..aec20f71 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 ### 0.9.2 (Next)
 
+* [#163](https://github.com/slack-ruby/slack-ruby-client/pull/164): Use `OpenSSL::X509::DEFAULT_CERT_DIR` and `OpenSSL::X509::DEFAULT_CERT_FILE` for default ca_cert and ca_file - [@leifcr](https://github.com/leifcr).
 * [#161](https://github.com/slack-ruby/slack-ruby-client/pull/161): Added support for cursor pagination - [@dblock](https://github.com/dblock).
 * Your contribution here.
 
diff --git a/lib/slack-ruby-client.rb b/lib/slack-ruby-client.rb
index 12d79387..f33cec71 100644
--- a/lib/slack-ruby-client.rb
+++ b/lib/slack-ruby-client.rb
@@ -17,6 +17,11 @@
 rescue LoadError
   # ignore, only used in users_search
 end
+begin
+  require 'openssl'
+rescue LoadError
+  # Used in slack/web/config
+end
 require_relative 'slack/web/config'
 require_relative 'slack/web/api/errors/slack_error'
 require_relative 'slack/web/api/errors/too_many_requests_error'
diff --git a/lib/slack/web/config.rb b/lib/slack/web/config.rb
index 128e1efc..0b5ca6d1 100644
--- a/lib/slack/web/config.rb
+++ b/lib/slack/web/config.rb
@@ -21,8 +21,8 @@ module Config
       def reset
         self.endpoint = 'https://slack.com/api/'
         self.user_agent = "Slack Ruby Client/#{Slack::VERSION}"
-        self.ca_path = `openssl version -a | grep OPENSSLDIR | awk '{print $2}'|sed -e 's/\"//g'`
-        self.ca_file = "#{ca_path}/ca-certificates.crt"
+        self.ca_path = defined?(OpenSSL) ? OpenSSL::X509::DEFAULT_CERT_DIR : nil
+        self.ca_file = defined?(OpenSSL) ? OpenSSL::X509::DEFAULT_CERT_FILE : nil
         self.token = nil
         self.proxy = nil
         self.logger = nil
diff --git a/lib/slack/web/faraday/connection.rb b/lib/slack/web/faraday/connection.rb
index 9a10811f..2a9af04f 100644
--- a/lib/slack/web/faraday/connection.rb
+++ b/lib/slack/web/faraday/connection.rb
@@ -11,7 +11,7 @@ def connection
 
           options[:headers]['User-Agent'] = user_agent if user_agent
           options[:proxy] = proxy if proxy
-          options[:ssl] = { ca_path: ca_path, ca_file: ca_file }
+          options[:ssl] = { ca_path: ca_path, ca_file: ca_file } if ca_path || ca_file
 
           request_options = {}
           request_options[:timeout] = timeout if timeout