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141  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 27, 2014, 09:55:48 AM
The length bits are only there to make distinctions between messages that otherwise would produce only zeros or messages that end with zeros which would give identical initial conditions without the length bits. So the length bits must be included. And the initial condition includes those length bits. In my previous version I added the length bits without including them in the number of bits of the initial condition.

I do not care of a variable length message, but am looking for the least complex irreducible computation hash for a block header. Message wrapping should be in an other logical layer either.

Here is what I get for a special pattern 80 byte input attempting to produce 32 bytes of hash after 5N length. It still fails.

142  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 27, 2014, 09:16:38 AM
It should start with the whole initial condition which includes the concatenated length bits

Sounds alchemy. You just hope that length in binary representation is not a specific pattern as above.
143  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 27, 2014, 09:10:21 AM
Wow. That's pretty nonlinear. Maybe my initial value of 4N is needed after all. Then the hash value will be taken from below where the slope crosses the center column. Unless the slope can bend nonlinearly the other way in some extreme ways. Tricky.

In degenerate cases you would even need 5N, see below for 010101... initial conditions
144  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 27, 2014, 06:25:17 AM
I run quite a few initial conditions to see that the slope is far from trivial, see example:

I see no safe lower bound for the slope yet.


145  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 27, 2014, 05:58:25 AM
Here you are from Wolfram, "Sensitivity to initial conditions"

https://www.wolframscience.com/nksonline/page-251?firstview=1
146  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 27, 2014, 05:41:56 AM
Yikes! It seems that 2.5 N is too small value too. Hmm... The chaotic mixing of Rule 30 needs to better understood.

Exactly. See the slope question I raised before.
147  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 27, 2014, 05:32:04 AM
It appears that neither of us had the right intuition. I plotted the effect of a bit on the outer right side. The question is: What is the slope of the yellow line?

148  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 27, 2014, 05:17:04 AM
You can try with 0.5 N which is the value needed for both left and right side of the initial condition to reach the center column. The hash values then become poor with similar messages producing similar hashes, without enough randomness needed for well approximation of a random oracle.

I have not seen the proof for above, yet. It is only your intuition against mine.
149  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 27, 2014, 05:07:42 AM
You see below that the hash is already part of the right side of an R30 evolution and that every bit of it has input from every bit of the value to be hashed.

150  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 27, 2014, 04:46:40 AM
The right side of the automaton is where the "randomness" is so the right value in blue needs to be mixed back into the center column:



Excuse, but that sounds arbitrary to me.
I am looking for the least complex but irreducible hash, and am not convienced that "mixing back" would be needed.

151  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 26, 2014, 09:04:30 PM
Does not "seem" to hurt.

152  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 26, 2014, 08:42:13 PM
Note that R30 has an apparent asymmetry in its "chaos".

The below pictures hint that left and right side of an input do not receive the same "kind" of hashing. Likely irrelevant, but puzzling.


153  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 26, 2014, 08:19:23 PM
Here is a version of the Rule 30 hash function that skips rows 2.5 times the number of bits in the initial condition: http://jsfiddle.net/d3NS6/

The reason is to ensure that the bits become influenced enough as a protection against cryptanalysis.

This sounds weak. This is the path to perceived security through perceived complexity, the thinking how SHA probably was constructed.

If there is really something with R30, then below should be sufficient.

154  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 26, 2014, 07:28:52 PM
I think Satoshi's solution to the Byzantine General's problem is the first real world application of Wolfram's computational irreducibility, since doing an irreducible computation is the ideal proof of work.

My intuition says that known attacks to hash functions are only special cases of reducibility checks and a computationally irreducible function must be resistant of them by definition.

Maybe SHA256 is also computationally irreducible, it is however more likely that irreducibility of an R30 hash will be rigorously proven, than that of SHA256.

It is desirable to use the least complex irreducible computation for proof of work, as that leaves least room for implementation differences. If R30 is irreducible then it is also the least complex of such.

Note that computation of the below area is sufficient.

155  Bitcoin / Development & Technical Discussion / Re: Rule 30 automaton as hash function on: July 20, 2014, 07:03:34 AM
Wolfram's computational irreducibility, if exists, defines the perfect proof of work, therefore the discussion is on spot here or better in an alt-coin forum.

I think that a simple POW algorithm eliminates the risk of possible shortcuts that might exist in complex algorithms like the SHA group.


156  Bitcoin / Development & Technical Discussion / Re: ANN: Announcing code availability of the bitsofproof supernode on: July 17, 2014, 07:35:52 AM
Stay tuned. You'll have a choice soon.
157  Bitcoin / Hardware wallets / Re: Trezor: Bitcoin hardware wallet on: June 21, 2014, 09:55:29 AM
Also a feature would be great is to be able to get the signed hex transaction, then we would be able to push our own transactions and wouldn't have worry about bits of proof not working!

Actually it is possible already. In javascript console (Ctrl+Shift+J in most browsers) there's hex dump of signed transaction when it is prepared to broadcast. Copy&paste to https://blockchain.info/pushtx works.

Of course that it is ugly workaround and I really hope it won't be necessary since we rebuild server side today.


a. there is some near abusive use of the service
b. a configuration change was made yesterday in an attempt to reduce race conditions that lead to problems a few times during last days, this change was not implemented consistently and lead to major disruption tonight. This is now corrected.

Services are back normal now and we work on addressing the race conditions.
158  Bitcoin / Development & Technical Discussion / Re: (non-ultimate) blockchain compression? on: May 30, 2014, 04:06:15 AM
I don't think a common disk compression methods are efficient for blockchain. Efficient compression means understanding the underlying structure.

Speaking on cheap vs expensive - I think it's users time that's more expensive than processor time or disk space. We can significantly save time necessary to wait for another wallet sync, or for a new wallet to init.

Block chain data does not compress impressively on a global scale, but indices on addresses and tx hashes do.

Bits of Proof stores both the block chain data and supplementing indices in LevelDB and achieves high performance in retrieving transactions referring an arbitrary HD master key, that is why it powers the myTREZOR web wallet.

I am sure it could be further optimized with your ideas, so let me know if you'd like to discuss them in that scope.
159  Bitcoin / Hardware wallets / Re: Trezor: Bitcoin hardware wallet on: May 27, 2014, 05:34:00 AM
This is awesome products, can you also integrate other cryptocurrencies, or only BTC?
If you read this page or the last one you would have seen that it's possible.
You can also read this:  http://www.bitcointrezor.com/faq/

If you are interested in alt currency use of myTREZOR and have good connections in those communities please contact me for a port of the Bits of Proof backend.
160  Bitcoin / Hardware wallets / Re: Trezor: Bitcoin hardware wallet on: May 23, 2014, 03:58:37 PM
one of the transactions has gone lost.

it was answered by tamas above: https://bitcointalk.org/index.php?topic=122438.msg6871010#msg6871010
it is a bug that some transactions are not visible to our backend and we are working on the fix.

There was an edge case were transactions were not reported to the UI, this should now be fixed.
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