DistOS 2014W Lecture 15

Designing Exercise

Can we do any kind of distributed system without crypto? We can't trust crypto...

What are the main features we need to consider for such a system ?

• Limited Sharing
• Integrity
• Availability

Perhaps probabilistically...

Want to be able to put data in, have it distributed, and be able to get it out on some other machine. This kind of sharing would need identification or authentication process.

Availability: "distribute the crap out of it", doesn't need crypto. No corruption of data.

Integrity: hashing, but we assume hashes can be forged. If we want to know that we got the same file, then simply send each other the file and compare.

Big Takeaway Everything you do with crypto is a refinement of what you can already do in weaker forms with weaker assumptions.

Note on Project Proposal

• Date has been extended until next week. As Prof said some of the proposals are not completely up to mark.