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1  Bitcoin / Development & Technical Discussion / [EDIT] A more 'difficult' algorithm for POW based on area? on: October 22, 2014, 01:32:57 PM
Block Hash (as big integer value)
|       -------------------------------+
|       --- *           #---#---# (C)  |
|            \         /               |
|             \       /               +---------------------(Difficulty bound)
|              \     /    
|               *---*---*---* (A)
|                \
|                 \
|                  \
|                   +---+ (B)
  n-1  n  n+1 n+2 n+3
n - Height

In the above diagram we represent three different block chains as curves where y(Block Hash as integer) and x(block Height n)

Correct me if i am wrong but according to current Bitcoin POW
Block chain (C) wins as the longest with adequate proof of work (sum of nBits)
Chains (A) and (B) although harder to generate don't count, as shorter.

What if we measured the area bellow each curve as Proof of work for a chain*?
Then a really low hash value in a chain would be taken into account making it further difficult to generate better curves given a known one.

*We would then have to minimize the area at given height.

You're proposing that the total work be based on the value of the individual hashes, instead of the hash targets, is that correct?

This could incentivize a miner who happens to find a hash with an unusually low value to refrain from immediately broadcasting it. See, for example, this attack proposed a few years ago by casascius, which becomes viable with this proposed change.
Thanks to btchris for feedback

As a measure of performance of a curve/blockchain in order to avoid the above attack we could sum the sign changes between two curves +1,0,-1 comparing curve values point wise and assuming max value were a curve lucks a point.

the scores of the curves would then became


2  Bitcoin / Mining software (miners) / Where in cgminer/BFG miner's src code TARGET is compared with current HASH? on: October 17, 2014, 10:50:46 PM
I don't have much of experience with mining so forgive any mistakes but I am a pro on C++/Hardware.

Basically interested on CPU / GPU mining.
I guess that with ASICs the target is passed as a parameter to the core.

Thanks in advance Smiley

3  Bitcoin / Development & Technical Discussion / Block timestamp must not be more than two hours in the future. What src file? on: October 17, 2014, 05:46:40 AM

Could some one help me locate where the following protocol rules are enforced in Bitcoin Core src.
What files should i read?

a) Block timestamp must not be more than two hours in the future.
b) Reject if timestamp is the median time of the last 11 blocks or before

PS. Perhaps the answer should be RTFM but I may miss something important.

Thanks in advance.
4  Bitcoin / Development & Technical Discussion / Difficulty! Do we really need it? on: October 14, 2014, 03:56:54 PM
Currently for a block hash to be accepted (proof of work) should have this form


 X's : Zeros
 Y's : Don't cares actual pattern depends on the difficulty

Difficulty Target  demands at least a minimum number of zero X's.
This requirement does not adapt well with sadden network hash power changes and the time required to find a hash may vary significantly.

We propose a different algorithm as proof of work that adapts well and works without specifying a Difficulty target.

Instead of Y's being don't cares we count the bit changes (0 to 1 transitions) within them.
So we force a block hash to satisfy two contradictory requirements due to the fixed bit length of the hash (256bits)
Counting 0 to 1 transitions a hash could have at max 128 something really rare.

Given two hashes with the same number of transitions the one with the most X's being zero wins.
I exact starting from the left and comparing the hashes bit by bit the first having 0 where the other hash has 1 wins.
(Dominant 0 bit)

How the network develops consciousness?
A) All participating nodes try to maximize hash 0 to 1 transitions
B) At given time intervals nodes publish their best so far
C) A node receiving two or more hashes always prefers the one with most transitions and if equal the one with most dominant 0 bits.
*A node that finds a really rare block and publishes it on time radically improves the security of the network.

This is preliminary work an we would like your comments or suggest similar works from others. Smiley
5  Bitcoin / Bitcoin Discussion / Why 1BTC should equal 10^8 satoshi ? on: October 11, 2014, 08:11:40 AM
If you come from a financial background then obvious choices are:

   0.0001       : a percentage in point (pip) is a unit of change specifically in foreign exchange markets
   1,000,000.00 : accountants favorite view

BUT if you come from a hacker/programmer or cryptanalyst background the

  0.00000000  is definitely what you would prefer  because resembles the 8 hex digits of a 4 byte (32bit) integer  0x1234ABCD

also note that values satoshi incide tx's are encoded Little Endian like this:
  40 4B 4C 00 00 00 00 00  - 0.05 BTC (5000000)
contrary to common practice that everything emitted to the network should encoded Big Endian

Any thoughts or better explanation?

PS: I find a representation like 1000.0001 the most clean for the average.
6  Local / Ελληνικά (Greek) / on: July 21, 2014, 01:47:59 PM
Δωμάτιο επικοινωνίας με δυνατότητα πραγματοποίησης οπτικοακουστικών κλήσεων και ανοικτή ακρόαση.

Αν βρίσκετε το IRC κανάλι #bitcoin-el feature limited o παραπάνω ιστότοπος μπορεί να σας φανεί χρήσιμος

PS. Δεν απαιτείτε εγραφή!

7  Local / Ελληνικά (Greek) / ΕΛΛΗΝΙΚΟΙ ΙΣΤΟΤΟΠΟΙ BITCOIN / BITCOIN GREEK WEB SITES on: September 08, 2013, 04:44:43 AM
Αν εχετε καποιο ιστοτοπο στα ελληνικα σχετικο με bitcoin και θελετε να ενημερωσετε την κοινοτητα
μπορειτε να τον αναρτησετε στο συγκεκριμενο topic ωστε να συμπεριληφθει στην παρακατω λιστα.

ΠΡΟΣΟΧΗ: Μονο ιστοτοποι στα ελληνικα, κατα προτιμηση γενικου ενδιαφεροντος και οχι ιστοτοποι που απλα δεχονται πληρωμες σε bitcoin
_______________________________________________________________________________ _______________________________
Α)Ενημερωτικοι ιστοτοποι.*

B)Socia Media*


Δ)Κατάλογοι (Yellow Pages)*

Ε) Ανταλλακτήρια*

Ε) Επικοινωνία*
_______________________________________________________________________________ _______________________________
Ενημερωθηκε: 15/04/2016

*)Η καταταξη ειναι τυχαια και δεν αποτελει σε καμμια περιπτωση αξιολογηση ενος ιστοτοπου.
8  Bitcoin / Development & Technical Discussion / [Bitcoin Client Feature Request] Option to explicitly set change bitcoin address on: June 19, 2013, 05:27:34 AM
I have been working with the bitcoin-qt client for some time.

Taking consideration of the recent changes in transaction fee policy
I started wondering of a feature easy to implement and test with major impact.

So far there is not any option to control the change address used by the client.

Being able to do so:
1) Would greatly reduce the number of addresses some one has to track.
2) Could help reduce resource usage and improve tracking of transactions
3) Would extend the validity of wallet backups and reduce lost coins

I am well aware of the security and privacy concerns behind currently avoiding to do so.

That's why i speak for an option.
Of course for security reason the permitted range of addresses should be limited to the ones in current wallet

If you find this worthy i would be glad to help implement it and hear your opinion.
9  Bitcoin / Development & Technical Discussion / Please some one fix this on: June 19, 2013, 01:45:58 AM
We have been running a Testnet3 block explorer for some time here

Visitor activity is small but you can can confirm  the recent buzz about asic miners using Testnet3.
( )

The wiki page about Testnet [ ] seems outdated
Could some one update it with the current status and let others know about us.

Thanks in advance

We cannot guaranty 100% up time but don't forget you are on testnet.
10  Bitcoin / Project Development / Testnet3 Blockexplorer [ ] on: June 11, 2013, 06:33:21 PM

11  Economy / Gambling / The simple bitcoin game [ ] on: June 07, 2013, 08:35:21 PM
We welcome any feedback reviews
Thank you so much
12  Local / Ελληνικά (Greek) / A simple bitcoin game [ ] on: June 07, 2013, 05:19:16 PM
Any feedback and comments are welcome.

Σχόλια και παρατηρήσεις ευπρόσδεκτα.   DEMO
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