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Messages - bytemaster

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General Discussion / Re: Scamming using bitcointalk nicknames
« on: November 08, 2013, 06:35:20 am »
If every forum supported Keyhotee ID this wouldn't be a problem ;)

I want to implement a pay-per-share mining pool and would like to know the equation for calculating PPS for a given block based upon difficulty, block reward, and share target.

I am thinking of setting pool shares to be 0x03fffffffffff............

Given pool shares of that difficulty and assuming a 0 average profit pool, what should my pay per share price be?

BitShares PTS / Re: Post your Mining Performance
« on: November 08, 2013, 03:51:41 am »
AMD FX6300 with 8Gb RAM

"hashespermin" : 13.74452367,

24 hours with nothing :(
is this normal?

at this rate yes. this is my machines, it might get you a feeling:

"hashespermin" : 50.06642312 --> 20 blocks
"hashespermin" : 41.14747421 --> 2 blocks
"hashespermin" : 25.34802261 --> nothing
"hashespermin" : 18.12231320 --> 1 block
"hashespermin" : 15.73872058 --> nothing
"hashespermin" : 11.80773078 --> nothing

I have a machine mining at 50 HPM that has only found 1 block and it started mining within the first hour.

General Discussion / Re: Trusted Forum Members
« on: November 08, 2013, 03:48:31 am »

anyone who is a moderator or admin..

Marketplace / Re: Buy Keyhotee ID with ProtoShares 100 PTS+
« on: November 08, 2013, 02:58:58 am »
Is that a better solution before a non-manual exchange exists?

Yes, because you can currently mine PTS easily enough and part of supporting Keyhotee is supporting ProtoShares so having a few extra bids helps.    An exchange will be available soon. 

Right now the number of people signing up for Keyhotee IDs is only a couple per day so they can easily get some PTS :) 

General Discussion / Re: $2000 Bounty - ProtoShares Mining Pool
« on: November 08, 2013, 01:50:27 am »

hi, the pts pool, the testnet is broken, so it is just a beta version!

Nice work, though the bounty is for a pool set up on my server so I can collect the fees :)

General Discussion / Re: $5000 Bounty - Momentum Proof-of-Work Hacking
« on: November 08, 2013, 01:49:03 am »
The results of the experiment in table 4 evoke some interesting discussion. If one excludes the preprocessing step, the
speed up is significant.

The preprocessing step however is an integral part of the
algorithm to port the Bloom Filter on to the GPU. Thus we
need to come up with better ways to preprocess a given set
of keys.

One more notable observation is that the actual
filter construction time and communication latency between
GPU and CPU is independent of the key size.

I haven't read the other papers... but so far it appears non-trivial.

General Discussion / $5000 Bounty - Bitcoin Wallet Interface for Keyhotee
« on: November 08, 2013, 01:29:12 am »
As many of you know Keyhotee will have a wallet interface.  I would like a developer to build the initial version of this interface with the following requirements:

1) Interfaces to bitcoind (or any compatible alt-coin)
2) Uses public/private keys from Keyhotee Profile Hierarchical wallets (I have already implemented the key generation)
3) Displays a list of all transactions & Balance
4) Allows the creation of new transactions for sending coins to a Keyhotee ID

I estimate that it would take me about 2 weeks full time dedicated to the effort to create the basic interface. 

The winner of this bounty also gets credit of $5000 toward their Keyhotee ID.

Marketplace / Re: Buy Keyhotee ID with ProtoShares 100 PTS+
« on: November 08, 2013, 01:08:05 am »
I have devised a solution to the problem of  declaring a price fix indirectly for my Keyhotee ID prices.

I will now ONLY accept payment for Keyhotee IDs via ProtoShares and will credit your ID with the market value of the ProtoShares as of Christmas Eve so you do not lose any appreciation and it all gets credited to your ID.

BitShares PTS / Re: Block Explorer
« on: November 08, 2013, 12:47:11 am »
Could you use the ProtoShares logo rather than the BitSHares logo for this block explorer? 


BitShares PTS / Re: ProtoShares Mining Schedule
« on: November 08, 2013, 12:45:22 am »
I thought the reward was supposed to decrease 5% a week.  It looks like it's decreasing around 5% a day.  Anyone have an explanation for this difference?

Mining rate is supposed to be every 5 minutes, but initial demand was so high that it has been closer to every 30 sec... once difficulty adjusts we we be back on schedule, perhaps accelerated by 1 month.   Note that Bitcoin also has this problem and is currently over a month ahead as well.

General Discussion / Re: $5000 Bounty - Momentum Proof-of-Work Hacking
« on: November 08, 2013, 12:43:36 am »
My replies..
I suppose the performance of your algorithm would also suffer if instead of SHA512(X),  SCRYPT(X) was used because the cost of doing this step twice would be much higher and less GPU friendly.

I wonder what would happen if we used NESTED momentum proof of work? 

Change the nonce-space of the outer proof of work to a pair of 16 bit numbers that result in a X-bit collision?

Now you have a more memory intensive inner hash that is still quick to validate, but would significantly complicate GPU miners.

Note the reason we selected a fast hash like SHA512 rather than a slow hash like SCRYPT is to maximize memory bus bandwidth. 

General Discussion / Re: $5000 Bounty - Momentum Proof-of-Work Hacking
« on: November 08, 2013, 12:41:59 am »
     Thank you for providing the first innovative algorithm for reducing the memory requirements.  Let me attempt to post mitigating factors to your algorithm.

     From a CPU miner perspective, your reduction in memory comes at the expense of performance so does break the algorithmic complexity of the algorithm.

     From a GPU perspective you have to populate a bloom filter with 2^26 results... based upon my understanding of how bloom filters operate this would require updating a common data-structure from every thread and the resulting memory race conditions could create false negatives.   If you have to do this step sequentially, then you might as well use a CPU with memory.   

     So do you have any solid algorithms that can populate a bloom filter with 2^26 results in parallel? 

General Discussion / Re: $5000 Bounty - Momentum Proof-of-Work Hacking
« on: November 08, 2013, 12:41:29 am »
I've managed to make a huge step forward in proving Momentum being not nearly as good for proof-of-work as intended.

The magic lies in using a Bloom filter to store the intermediate hashes.
As a result, instead of using 12 bytes per hash/nonce in a Semi-Ordered Map (which results in ~750 MB of memory), the required memory is (-1 * (2^26 * ln(0.01)) / (ln(2)^2)), or about ~76 MB.

This number can be reduced arbitrarily if we're willing to have a false positive rate greater than 1%.  For example, if we allowed up to a 50% chance of having a false positive, the memory requirement drops to ~11 MB.

Here's a overview of how the algorithm works:

Make a "main" bloom filter of size 2^26 with a false positive rate 1%: ~76 MB
Make a tiny "clash" bloom filter of size 2^16 and false positive rate 2^-26: ~0.7 MB
Make a vector of pairs< hash, nonce > to store candidate birthday collisions.
For each nonce in the search space, check if its hash exists in the "main" bloom filter.  If it is, add it's entry to the "clash" bloom filter.
The "main" bloom is no longer required and can be discarded.
For each nonce in the search check if its hash exists in the "clash" bloom filter.  If it does, add < hash, nonce > to a candidate list for investigation.
Sort the list of candidates by hash.
For each pair in the candidate list, see if the previous element has the same hash.  If it does, add it to the output list.  This step removes false positives by comparing the actual hash instead of the bloom filter's idea of a hash.
Return the output list as normal.

For your testing pleasure, I also built a working proof of concept.
(Most of the magic is right here.  The bloom filter is a modified version of "bloom.cpp" called "bigbloom.cpp")

Unmodified source:

Source using bloom filters:

In exchange for lowering the memory requirements by a factor of ~10, the algorithm runs at about 1/4th speed, mainly due to the doubling calls to SHA512 and the hash calls within the bloom filters.  The overall result is a net efficiency gain of approximately 2.5
The reduction in memory requirement means that if we could fit N instances of Momentum in GPU memory, we can instead fit 10*N instances.  If we up the false positive rate in exchange for more time spent sorting, we can achieve ratios of up to 70*N.

Given that bloom filters, SHA512, and sorting data are all parallel/GPU friendly, we can conclude that Momentum as a proof-of-work isn't nearly as GPU-hard as initially intended.

General Discussion / Re: $5000 Bounty - Momentum Proof-of-Work Hacking
« on: November 08, 2013, 12:40:37 am »
Thanks. I still think you're underestimating the issue. I think you should change it to have a large nonce space much larger than anyone could store in memory so that you have asymptotically linear scaling in terms of RAM.

Could you clarify what exactly you require in order to claim the full bounty?

Nathaniel,  to collect the full bounty I must be convinced that a momentum derived proof-of-work is not much better than SCRYPT at hindering an ASIC take over.    There is clearly a lot to learn about the structure and behavior of this class of proof-of-work.   From what I can tell it is still clearly the best proof-of-work system conceived of thus far.     

Let me repost an attack on this proof of work from bitcointalk for discussion here.

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