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Nope, today's CDNs are all location-based, not content-based. The user-agents are requesting content based on the address (the URI), not based on the content-hash of the content. The CDNs might work content-based internally, but the user-facing web CDNs definitely are URL based, not content-hash based.

[Chabsff]

You might have a point if this was a user problem, but it's not. It's a site operator problem. And from their POV, a CDN provides the exact same functionality.

[embedding-shape]

CDNs are hack, not a solution. Content-addressing would be a solution, not a hack. From the PoV of operators or users doesn't matter, DDoS wouldn't be viable with content-addressing.