As a temporary workaround, I have tried and tested the following. My hCaptcha keys are ready prepared:
In the stripe-payments plugin folder, make a backup of the recaptcha folder – that means you have a copy if it all goes toes up. Changing anything in core files is not recommended, use at your own risk, yadda yadda…
Open stripe-payments > recaptcha > asp-recaptcha-main.php and make the following four changes:
1) Line 53, change the URL
https://www.google.com/recaptcha/api/siteverify
to
https://hcaptcha.com/siteverify
2) Line 245, change the URL
https://www.google.com/recaptcha/api.js?onload=onloadCallback&render=explicit
to
https://js.hcaptcha.com/1/api.js?onload=onloadCallback&render=explicit
3) Line 261, change the URL
https://www.google.com/recaptcha/api.js?onload=onloadCallback&render=explicit
to
https://js.hcaptcha.com/1/api.js?onload=onloadCallback&render=explicit
4) Line 324, change the URL
https://www.google.com/recaptcha/api.js?render=explicit
to
https://js.hcaptcha.com/1/api.js?render=explicit
Save and upload to your server. Login in to WordPress and find the settings page for the plugin. In the reCAPTCHA tab, check ‘enable reCAPTCHA’, leave invisible unchecked, and enter your hCaptcha site and secret keys. Save the settings.
Optional but strongly advised: put Stripe in to test mode and make sure the hCaptcha works as planned.