Google's John Mueller said a link on an HTTP page is just as valuable to Google as a link on an HTTPS page and visa versa. He said on Twitter "we treat links on http the same as links on https sites." So there is no benefit to having a link from a page that is secure or not secure.
This is after Natalie Coyne posted a Twitter poll asking about this:
Hey #SEOs, Iām having an internal discussion here and need some external input. Do non-secure sites pass LESS authority or page rank than secure sites? #SEO #DigitalMarketing #SEOBeers #HappyFriday
— natalie coyne (@nataliecoynestl) January 10, 2020
Here is John Mueller's response:
I don't know about authority, but we treat links on http the same as links on https sites.
— š John š (@JohnMu) January 10, 2020
Reason he said I don't know about authority is that he said numerous times, Google doesn't use authority.
In any event, this reminds me of when SEOs began selling HTTPS links after the HTTPS ranking boost came out. Too much fun, don't you think?
Forum discussion at Twitter.