Well ... cannot really since x_fp_hash is not returned as a param
<input class="textInput" id="x_login" name="x_login" type="hidden" value="4s8QPsNt9a" /><input class="textInput" id="x_ammount" name="x_ammount" type="hidden" value="111.0" /><input class="textInput" id="x_fp_sequence" name="x_fp_sequence" type="hidden" value="1368566616" /><input class="textInput" id="x_currency_code" name="x_currency_code" type="hidden" value="USD" /><input class="textInput" id="x_fp_hash" name="x_fp_hash" type="hidden" value="2c24a50c4edf9b524fdff5c2e8c7e8e9" /><input class="textInput" id="x_fp_timestamp" name="x_fp_timestamp" type="hidden" value="1370333787" /><input class="textInput" id="x_type" name="x_type" type="hidden" value="AUTH_CAPTURE" /><input class="textInput" id="x_test_request" name="x_test_request" type="hidden" value="FALSE" /><input class="textInput" id="x_version" name="x_version" type="hidden" value="3.1" /><input class="textInput" id="x_relay_response" name="x_relay_response" type="hidden" value="TRUE" />
{"x_test_request"=>"true", "x_amount"=>"0.00", "x_ship_to_state"=>"", "x_ship_to_first_name"=>"", "x_cust_id"=>"", "x_city"=>"", "x_auth_code"=>"000000", "commit"=>"", "x_ship_to_city"=>"", "x_ship_to_last_name"=>"", "x_email"=>"", "x_state"=>"", "x_avs_code"=>"P", "x"=>{"month"=>"2", "year"=>"2015"}, "x_MD5_Hash"=>"ECDA29B57FFCCE5D27B3C77248B04DF8", "x_fax"=>"", "x_company"=>"", "x_account_number"=>"", "x_first_name"=>"", "x_po_num"=>"", "x_invoice_num"=>"", "x_country"=>"", "x_address"=>"", "x_last_name"=>"", "action"=>"relay_response", "x_ship_to_country"=>"", "x_ship_to_zip"=>"", "x_ship_to_address"=>"", "x_ship_to_company"=>"", "x_type"=>"auth_capture", "x_trans_id"=>"0", "x_tax_exempt"=>"FALSE", "x_tax"=>"0.00", "x_zip"=>"", "x_card_type"=>"", "x_response_code"=>"3", "x_duty"=>"0.00", "x_ammount"=>"111.0", "x_freight"=>"0.00", "controller"=>"authorize_net", "x_cavv_response"=>"", "x_phone"=>"", "x_cvv2_resp_code"=>"", "x_description"=>"", "x_method"=>"", "x_response_reason_text"=>"(TESTMODE) This transaction cannot be accepted.", "x_response_reason_code"=>"99"}