In what way?

that's what i want to know!

On 02/06/2014 02:08 PM, Charles Goyard wrote:

Hi,

i go bananas wrote:

...

...

In what way?

that's what i want to know!

If that's a general question, then the answer is yes, as you can get and send bytes over a network and do math with pd. It's also the answer for all general questions like "can I do something a computer does with pd ?"

It does not mean it fits you needs, or the amount of work you want to put in :).

Not giving contexts does not lead to useful answers.

That's a self-fulfilling prophecy.

It also turns out to be wrong, because I made another self-fulfilling prophecy which turns out to be useful.

-Jonathan

So, do you have something in mind ?

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On 02/06/2014 11:03 AM, i go bananas wrote:

...

In what way?

that's what i want to know!

I don't know the specifics, but I think both cryptography and finance are areas where the feature of "everything is a float" actually gets in the way. In either case you cannot afford to lose precision.

But you can prototype some of the features of a cryptocurrency in Pd.
For example, Bitcoin uses the hashcash algorithm to verify each block of the transaction database. (If I understand it correctly it's like brute-forcing SHA256 keys, although they never completely succeed.) The miners basically start a counter, do a mathematical function on the value plus the previous value from the last entry in the transaction database, and finally check if the output has a certain number of leading zeros.

If you ignore for the moment the counter and the mathematical function, you can see how the process works. Attached is a patch that just keeps spitting out pseudo-random numbers between 0 and 1 until all of the [random] objects happen to output zeros. It's essentially like a slot machine that keeps playing until you win. Now notice that when you hook up another [random] to the chain you double the average time it takes to find a "winner". Add enough [random] objects to the chain and you will quickly hit a point where you can't compute a "winner" at all (even if you change the patch to compute answers as fast as possible).

Bitcoin's "block difficulty" uses the same principle. The software has a hardcoded rule that it should take 10 minutes to find a "winner". But instead of using a bunch of binary values, it uses a single number and requires the "winner" to be below a certain value (which is equivalent to counting the leading zeros in the representation of the number).
Over a certain number of days it measures the average time it takes the network to compute a "winner". If it's way less than 10 minutes on average then the software automatically does the equivalent of adding a [random] to the patch to make it twice as hard. If it takes too long then the software removes a [random]. The actual algo is probably more sophisticated but that's what it boils down to.

Now, let's say you hook up 50 [random] objects in that patch and happen to find a "winner". That'd be pretty spectacular, but how do you convince everyone that you are being truthful about your claim? This is where the hashing function and the counter come into play. Instead of the attached patch, imagine a [hash] abstraction that takes a counter value in the left inlet and the previous transaction hash in the right inlet. It will output a seemingly unrelated number in response to the input, but that number will be unique to the input you give it (or so close to unique that we can just call it unique). That's what a hashing function does. So you essentially do the same thing you did above, except you're looking for leading zeros in a single number rather than the collective output of a bunch of [random] objects.

When you hit a "winner" you then broadcast your counter value and the new transactions to the rest of the network to add to the database. The rest of the network already has the previous entries in the transaction database, so they can take those with your counter value and verify that the resulting hash actually has the correct number of leading zeros.
Then everyone starts working on the next "winner". And why do they do that instead of trying to lie and say they were the one that actually found the "winner"? Because the first new transaction in the database is the real winner giving 50 bitcoins to themselves, and that transaction uses public key cryptography to ensure that it can't be forged or changed.

One last thing-- the hashing function is designed so that it's extremely difficult (read: impossible) to start with a hash value that has the required number of leading zeros and work backwards to figure out the right counter value. Like a slot machine, you have to just keep trying until win. And just like a slot machine, if someone can figure out how get a winner without putting in the same work/money everybody else does, then the entire system breaks down.

-Jonathan

On 07/02/14 09:56, Thomas Mayer wrote:

On 06.02.2014 10:09, i go bananas wrote:

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Has anything been done to try to marry these together yet?

PuREST JSON includes a sonification for Bitcoin values going back to 2011, but I guess, that is not what you wanted to know.

it sounds the more likely kind of dsp/bitcoin marriage, otherwise perhaps a pd concert with the ticket price in bitcoin???

simon