Here's a simple example: perform the computation in the exponent over a finite field. Let's say you're doing linear regression and need to compute a*x+b. I'm going to pick a number g and give you g^x instead of x. You're going to compute g^(a*x+b) = (g^x)^a*g^b. Now you can twiddle a and b to fit a line. But you don't know the data x (because inverting g^x is computationally hard, aka the discrete logarithm problem). Note 1: this is vastly oversimplified to demonstrate the idea. Note 2: this is partially homomorphic encryption -- you can't multiply two hidden numbers in the exponent -- this is what is added by fully homomorphic encryption, which pulls in a mountain of new headaches.

Give me another way to turn real-world assets into cryptographic form without "trusting" someone.

Bram founded a new company, https://chia.net/ which is making a new bitcoin-derived crypto-currency based on Proof of Space and Time. Basically it fills the unused space on your drive with entropy, and uses this like a set of lottery tickets instead of Proof of Work mining. They're also focusing on features of the crypto-currency that will enhance "Layer 2" (like http://lightning.network/) to enable scalability. In an economic sense this construction shifts the costs of mining toward capital expenditure (for storage) instead of electricity consumption.

He and a collaborator recently won Best Paper at Eurocrypt 2018 for a Zero Knowledge Proof of Time https://eprint.iacr.org/2018/1... (presentation: https://cyber.stanford.edu/sit... )

Interesting things are coming from Bram.

They're shooting protons at a LiF2 or LiO2 solid target. Why do we think there is not a (p,F) or (p,O) reaction contributing to this?

As a long time reader, I'm pretty severely disappointed by the responses to this post. No discussion of NTP, or GSM time distribution, or CDMA time distribution, or shortwave radio, or ANYFUCKINGTHING relevant to the poster's question.

Where did the knowledgeable people go? Because I really don't need some douchenozzle to tell me that the Amazon fire has a clock app, and see that that post has been rated +4?!?!?! WTF?!??!?!

Give mod points motherfuckers and I will clean up this mess.

It's hard to believe psychology studies are more reproducible than cancer studies (11% reproducible): http://www.nature.com/nature/j...

Unless you want to spend several months a year of your life auditing inefficient "charity" organizations and trying to make judgments about whether they're doing it right and spending your dollars wisely...and hey if you think you're good at that you should probably start your own charity. But if you do, everyone will expect you to work for free. It's a viscous circle.

Donate your time, you'll meet people too.

Unless you're a multi-billionaire, then start a foundation and direct where the money goes.

Also this is an awesome graph, and illustrates that the Earth is a horrible clock: https://upload.wikimedia.org/w...

The whole problem strikes me as one of human preferences, not technical requirements. There's absolutely no reason not to use our atomic clocks and just count number of seconds since some starting point. The desire to have the sun directly overhead at "noon" is a human one, divorced from any technical requirement. All of science, computing, networking, telecommunications, would be much happier if we didn't continually redefine time like this.

So let watch manufacturers and clock-app manufacturers deal with this, when reporting time for human consumption. It shouldn't be a problem for NIST and government bodies. NIST should instead be reporting Earth's orbital parameters as time delta from noon, as they change over time, not conflating time itself with Earth's orbital parameters.

This is the way GPS, Loran-C and TAI handle time, and it's the right thing to do.

This entire article makes me seriously question Slashdot as a hangout for anyone who passed high school. Anyone who asks this question should not be employed as a software engineer either.

the paperwork involved with understanding and filling out dozens of tax returns in langauges you don't speak would just be overwhelming

But somehow marketing in all these different languages isn't overwhelming enough to stop them from selling their goods in these countries. And if you're worried about efficiency, let's remember that it would be FAR more efficient to only tax corporations, than to tax EVERY SINGLE CITIZEN.

Coffee shop employees are perfectly capable of skimming credit cards so they can perform illicit transactions also. I've had that happen to me too. The technical ability to so easily skim numbers is what enables fraud. There's no encryption there.

"I never authorized that charge" was not sufficient for my bank. So then it's off to court...

Because the courts are the best way to reverse transactions. I've had the scenario you describe regarding road tolls and car rentals, and I challenged it with my bank. Got me exactly nowhere. I suppose I could go to court for a $75 fine, but who has time for that?

Legally some jurisdictions may consider it a one-time charge, but technically they have everything they need to perform a second charge, and it's your blood sweat and tears to challenge the fraud. That waiter skimming cards will not be deterred by your long, expensive, legal-system charge reversal plan.

The non-anonymity of MC transactions is a huge liability. Not only does my MC payment for my coffee allow me to pay for my coffee, but it also allows the merchant to perform future transactions (whether valid or not). It's an authorization not a one-time transaction. This price is just too high and is the source of all CC fraud. There is no reason why any merchant needs to know who I am. If customers choose to disclose their identity to sign up for their email spam, that's their problem, but I should not have to pony up my identity to perform most consumer transactions. The only reason merchants check ID's on transactions is as a flawed fraud protection measure. It protects them, but at my expense.

Anonymous transactions are be better.

Him theory is not considered credible by anyone I've ever talked to (I am a theoretical physicist). I can't really say more, I haven't studied it.

And we all hope a method to compute at strong coupling will arise. And if one does, one could computer the bound state spectrum of the dark matter sector, and do the calculation the authors suggest correctly. Maybe their suggestion is even correct, but their calculation is wrong without consideration of bound states.