We recently added signature authentication for Harvesters who accept online payments using PayPal Website Payments Pro (WPP). Previously you could only connect Harvest with your PayPal WPP account using a downloadable certificate. Now you can link the two with a signature. Both options are PayPal SSL encrypted and secure.
If you would like to switch from certificate to signature authentication (and vice versa) simply change the settings in your PayPal and Harvest account. Visit our help section to learn more about setting up PayPal Website Payments Pro for online invoicing.