hCaptcha - Alternative to reCAPTCHA
hCaptcha is basically the same as reCAPTCHA, with some major differences:
1) They respect the privacy of your visitors.
2) The problems visitors solve are not for the benefit of a single company.
3) You can earn money, or donate it, by visitors solving these problems.
Is another platform where it can serve has an alternative rather than relying on a Google service for everything.