Add SignatureService

spec/services/signature_service_spec.rb

@@ -0,0 +1,16 @@
+require 'spec_helper'
+
+describe SignatureService do
+  let(:service) { SignatureService }
+  let(:message) { { hello: 'World!' }.to_json }
+  let(:message2) { { hello: 'World' }.to_json }
+
+  it "sign and verify" do
+    signature = service.sign(message)
+    signature2 = service.sign(message2)
+
+    expect(service.verify(signature, message)).to eq(true)
+    expect(service.verify(signature2, message)).to eq(false)
+    expect(service.verify(signature, message2)).to eq(false)
+  end
+end