To encrypt payment information, you need to create a Payment Processing Certificate, and associate it with your Merchant ID.
- Log in to your Apple Developer account at https://developer.apple.com.
- Click Certificates, Identifiers & Profiles.
The page loads and presents a menu.
- Click Merchant IDs.
- Select your merchant identifier and click Edit.
- In the Payment Processing Certificates section, click Create Certificate.
- Select No to Will payments associated with this Merchant ID be processed exclusively in China? and click Continue.
- Click Continue.
- Upload the CSR file that you received from Adyen, and press Continue.
- Click Download to download the .cer file and press Done.
- Email the .cer file to firstname.lastname@example.org.
Once support confirms that the certificate is activated, you're able to process ApplePay for in-app. For web, you also need to enable Apple Pay on the web.