Web Caching

Trust

When viewed in a broader sense, many of the issues surrounding web caching can be reduced to matters of trust. Cache users must trust administrators not to reveal private information contained in cache log files. This relationship is analogous to those we have with banks, telephone service providers, and movie rental companies.

A very informal trust relationship often exists between cache operators and content providers. In a sense, cache operators trust they will not face litigation, and content providers trust caches to have reasonable expiration and refresh parameters. Of course, some trust more or less than others, and when this tenuous relationship breaks down, both parties seek to regain control. Content providers may turn to cache-busting techniques, and cache administrators to server-busting.

Perhaps the thing we most take for granted is that our caches deliver correct content to users. While it is perhaps unfortunate that we must place so much trust in this aspect of web caching, it is not necessarily unique. As users, we also generally trust that our email messages are authentic and unmodified. At least with email we have some good solutions to this problem (e.g., PGP). The Web will catch up eventually.