add code to test HMAC message validation (#95)

Author: karissarjacobsen

connect_test.rb

@@ -0,0 +1,19 @@
+def ComputeHash(secret, payload)
+  require 'openssl'
+  require 'base64'
+
+  digest  = OpenSSL::Digest.new('sha256')
+  hashBytes = OpenSSL::HMAC.digest(digest, secret, payload)
+  base64Hash = Base64.encode64(hashBytes)
+  return base64Hash;
+end
+
+def HashIsValid(secret, payload, signature)
+  ver = ComputeHash(secret, payload)
+  OpenSSL.secure_compare(ver.chomp, signature)
+end
+
+secret = 'xxoxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxGE=' # Replace this value with your own secret
+signature = 'c60xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxew=' # Replace this value with your own signature
+payload = File.read('payload.txt') # Read the payload from a file named payload.txt
+puts HashIsValid(secret, payload, signature) # should return true for valid