Caching of web content based on hashes?

Is it possible to extend the Subresource integrity specification to allow
for caching of web content based on hashes instead of max-age? This would
allow for longer caching of objects and may speed up the web due to making
cache control easier for web developers and proxies.

http://w3c.github.io/webappsec/specs/subresourceintegrity/

Best regards,
Christian Nygaard