diff --git a/README.md b/README.md
index 9c18a4d..6634eda 100644
--- a/README.md
+++ b/README.md
@@ -208,7 +208,7 @@ This provided signature [should](https://onfido.com/documentation#webhook-securi
 
 ```ruby
 if Onfido::Webhook.valid?(request.raw_post,
-                          request.headers["X-Signature"],
+                          request.headers["X-SHA2-Signature"],
                           ENV['ONFIDO_WEBHOOK_TOKEN'])
   process_webhook
 else
diff --git a/lib/onfido/resources/webhook.rb b/lib/onfido/resources/webhook.rb
index b43f08c..1d80ca6 100644
--- a/lib/onfido/resources/webhook.rb
+++ b/lib/onfido/resources/webhook.rb
@@ -29,7 +29,7 @@ def self.valid?(request_body, request_signature, token)
     end
 
     def self.generate_signature(request_body, token)
-      OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('sha1'), token, request_body)
+      OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('sha256'), token, request_body)
     end
     private_class_method :generate_signature
   end
diff --git a/spec/integrations/webhook_spec.rb b/spec/integrations/webhook_spec.rb
index 489a3a7..7004d35 100644
--- a/spec/integrations/webhook_spec.rb
+++ b/spec/integrations/webhook_spec.rb
@@ -53,13 +53,17 @@
     end
 
     let(:request_body) { '{"foo":"bar"}' }
-    let(:request_signature) { 'fdab9db604d33297741b43b9fc9536028d09dca3' }
+    let(:request_signature) do
+      '89e60408fec20bfb26bb0f993d5e88307818982f50f23b361a00d679bae8b1dc'
+    end
     let(:token) { 'very_secret_token' }
 
     it { is_expected.to be(true) }
 
     context "with an invalid signature" do
-      let(:request_signature) { '2f3d7727ff9a32a7c87072ce514df1f6d3228bec' }
+      let(:request_signature) do
+        'e1ad1c23078824debd18b2dee222506167cf28921a2a42f9c05e2426e51ad986'
+      end
       it { is_expected.to be(false) }
     end