Magento 2 Authorize.net Setup Guide To Fix MD5 and API

This is to help you make Authorize.net work in Magento 2.1.7. Though it is not clear, Magento 2 forces you to use md5 hash, and this hash has to be 10 characters (tried a longer one and it will give a random error). Also, you need to enable the Transaction Details API

To set this up properly:

Go here: http://www.miraclesalad.com/webtools/md5.php type in any string and copy the first 10 characters of the generated hash
At authorize.net go to Account > Settings > Security Settings > MD5-Hash and paste the generated has in the 2 inputs
Go to your Magento 2 admin panel and paste the md5 hash in the authorize.net settings
To enable the transaction details api go to the account >Security Settings > Transaction Details API and enable it, you will need to verify your security question to do so. This is to resolve the error: “Access denied. You do not have permissions to call the Transaction Details API”
Clear your Magento 2 cache