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1  Economy / Speculation / Echoes of the past on: December 08, 2013, 05:44:29 AM
Put your tinfoil hats on, gentlemen. The similarity between the value of gold during the Weimar inflation and the USD/BTC price increase is cunning.

It also indicates that this correction will be short lived before we enter the final stages of the end game.

2  Economy / Auctions / ASICMINER fixed price auction 4.5BTC/share, 1000 shares on: July 01, 2013, 05:10:07 PM
Bitfountain has emerged as the most competent player in the bitcoin mining industry. The recent rally of the ASICMINER equity leads me to another offering.

I am thus offering this FIXED PRICE auction for a total of 1000 shares at a price of 4.5 BTC/share.

The minimum amount of shares is 20 and you could decide to buy incrementally. I will post daily summaries. This auction will continue until the shares have sold out. The shares are sold on a first come first serve basis. I accept offers per pm, in case a buyer wants to stay anonymous. I will post the corresponding entry in the thread, so everybody is aware of the activity. The time of the PM counts as the bid time.

I have already performed a successful auction in March and June (https://bitcointalk.org/index.php?topic=148198, https://bitcointalk.org/index.php?topic=213729.0) and this is the third one. If you're unsure on how this auction style works, study the previous ones.

Please do your due diligence with respect to the viability of the investment. The shares are direct shares. This means that you have to setup a bitcoin address which you have the private key for, and communicate the BTC address to me to finalize the transition. This bitcoin address will serve as the primary target for dividend payments and authentication.

When you bid, you will receive a receipt which contains a dedicated payment address and instructions and is signed by my shareholder address handle [1KbAD8KU1u6uw6nHSJEYpdZfgQbNbTAkH2] using the software Armory. Payment follows the logic of the pay to contract model. I expect payment 48 hours of creating the receipt. Please make sure to have cryptographic proof of sending the payment, e.g. buy owning the private key of the originating bitcoin address.

If the BTC are not received within 48 hours, the bid becomes invalid and the shares are available again.

I plan to do the clearing twice a week (sunday/wednesday). If dividends overlap with the reporting/bidding, the date of the bid decides on the final recipient of the dividend, i.e. they will be forwarded correspondingly.

Happy bidding
3  Economy / Auctions / ASICMINER fixed price auction 2.5BTC/share, 2000 shares on: May 23, 2013, 01:19:55 AM
Bitfountain has emerged as the most competent player in the bitcoin mining industry.  With the recent appreciation of the ASICMINER equity from undervalued to fair valued, it is time for me to let go of some of the equity. I am currently holding 10000 shares, which can be verified at https://blockchain.info/tx/3c07216fce4bd45d0c7d49eabe21a4c137691e481527d0f936b65e49bc7bb7cf by looking up my address: 1KbAD8KU1u6uw6nHSJEYpdZfgQbNbTAkH2

I am thus offering this FIXED PRICE auction for a total of 2000 shares at a price of 2.5 BTC/share.

I am selling in chunks of 100 shares (thus 20 allocations of 100 shares) and you could decide to buy incrementally. I will post daily summaries. This auction will continue until the shares have sold out. The shares are sold on a first come first serve basis. I accept offers per pm, in case a buyer wants to stay anonymous. I will post the corresponding entry in the thread, so everybody is aware of the activity. The time of the PM counts as the bid time.

I have already performed a successful auction in March (https://bitcointalk.org/index.php?topic=148198.msg1572973#msg1572973) and this is the second one. If you're unsure on how this auction style works, study the previous one. However, please be advised that I am selling only in increments of 100 shares (250 BTC) this time.

Please do your due diligence with respect to the viability of the investment. The shares are direct shares. This means that you have to setup a bitcoin address which you have the private key for, and communicate the BTC address to me to finalize the transition. This bitcoin address will serve as the primary target for dividend payments and authentication.

After bidding, please sent the corresponding amount of BTC (shares*2.5) within 48 hours to the address I have registered with ASICMINER: 1KbAD8KU1u6uw6nHSJEYpdZfgQbNbTAkH2
Please make sure to have cryptographic proof of sending the payment, e.g. buy owning the private key of the originating bitcoin address. Alternatively ask me for an individual payment address.

If the BTC are not received within 48 hours, the bid becomes invalid and the shares are available again.

I plan to do the clearing twice a week (sunday/wednesday). If dividends overlap with the reporting/bidding, the date of the bid decides on the final recipient of the dividend, i.e. they will be forwarded correspondingly.

Happy bidding
4  Alternate cryptocurrencies / Altcoin Discussion / ppcoin stake generation tournament on: March 13, 2013, 09:51:51 PM
Abstract
=====

A perpetual tournament is proposed, in which stake holders try to compete against each other for generating the longest consecutive fork. This will provide an empirical means to investigate the security of the ppcoin network and show strengths and weaknesses of the current scheme.

Discussion
=======
The network security model of ppcoin is based on the premise that no particular stake holder can generate POS blocks faster than the network, i.e. the remaining stake holders combined. While this feature is implied by the proportionality between stake generation power and the amount of stake used at any given time, the proportionality is not proven yet. In fact, as the pre-0.3.0 version showed, it is not guaranteed for cases when stake generation power can be augmented by the use of computational power.

Due to incentive and time limitations, a thorough investigation of the POS scheme takes time. To advance this issue, I'd like to propose an empirical way of investigating the effectiveness of individual strategies to augment (temporarily) the stake generation power (POS blocks/time).

Since such a tournament would require lifting the checkpointing mechanism, which currently protects ppcoin from this vulnerability, it would likely have to be carried out on the testnet. However, even better, a special purpose tournament-net could be declared which could be equipped with features important for carrying out such a stress test.

I invite for a discussion of how such a tournament should look like. Comments are highly appreciated.
5  Economy / Auctions / ASICMINER fixed price auction on: March 01, 2013, 10:12:48 PM
Bitfountain decided to postpone the release of the ASICMINER equity to a trading platform.
(https://bitcointalk.org/index.php?topic=99497.msg1571278#msg1571278)

I am thus offering this FIXED PRICE auction for a total of 2472 shares at a price of 0.5 BTC / share.
I am doing this to provide liquidity and to benefit from my early investor status.

The minimum purchase is 10 shares and you could decide to buy incrementally. I will post daily summaries.
This auction will continue until the shares have sold out. The shares are sold on a first come first serve basis.

After bidding, please sent the corresponding amount of BTC (shares*0.5) within 48 hours to the following address:
1KbAD8KU1u6uw6nHSJEYpdZfgQbNbTAkH2

!!!IMPORTANT!!!
When you bid, specify the BTC address from which the BTC are coming from, so I can associate the forum name with the BTC address. Thus make sure you have access to the private key of the source BTC address. I will also use that BTC address when reporting the trades to friedcat. So safe yourself a headache and make sure you got this covered.
!!!IMPORTANT!!!

If the BTC are not received within 48 hours, the bid becomes invalid and the shares are available again.

I plan to do the clearing,i.e. the reporting to friedcat, after the auction has finished. If the auction takes longer than a week, I will report incrementally, i.e. each week.

If dividends overlap with the reporting/bidding, the date of the bid decides on the final recipient of the dividend, i.e. they will be forwarded correspondingly.

Happy bidding
6  Alternate cryptocurrencies / Altcoin Discussion / ppcoin POW exposure on: February 28, 2013, 04:31:40 AM
Abstract
========

The longterm viability of the POW/POS hybrid system is discussed, in particular the exposure of ppcoin to double spend attacks facilitated by the generation of POW blocks. It is conceivable that entities or individuals with superior hashing power used to mine bitcoin have a vested interest to perform double spent attacks on a competing cryptocurrency. This is economically feasible since there are no network security trust issues with performing a double spent attack on a competing blockchain and the reduced POW requirements for ppcoin sets the bar lower for a temporary 51% attack.

Discussion
==========

While I didn't have time yet to do a thorough review of the 0.3.x changes to the POS generation in ppcoin, I'd like to discuss a feature of the hybrid POS/POW system in general. In particular I am interested in a potential vulnerability for double spending attacks which stems from the existence of a 100% POW blockchain with the SAME hashing algorithm, i.e. bitcoin.

The POW in ppcoin serves the purpose to solve the initial coin distribution problem and to set the stage for its inflation policy. It was the main generator for transaction blocks in the beginning of ppcoin, a feature which becomes more or less obsolete, now that POS is taking charge of generating blocks.

The fact that ppcoin uses the same hashing algorithm as bitcoin makes it possible for someone to easily switch between the two networks for mining. This is a curse and a blessing at the same time. While it feeds off a larger user base for mining, it also exposes ppcoin to a 51% attack vector as long as the total hashing power of ppcoin is not comparable to bitcoin. E.g. currently the hashing power of the bitcoin network is around 30 TH/s at difficulty of 4.3M and that of ppcoin is assumed to be between 10-100 GH/s at a dfficulty of 15k (the relationship between hashing power and difficulty is warped in ppcoin [https://bitcointalk.org/index.php?topic=140800.msg1499495#msg1499495]). Thus it requires a hashing power of 10-100 GH/s to gain a majority of ppcoins hashing power. This is already feasible by many players in the bitcoin mining industry, and certainly possible by individuals who own ASICs.

The question then is, how to remove this exposure. There are several options:
a) increase the incentive to mine ppcoin and raise the hashing power of ppcoin to make the economic cost for a double spent attack comparable to bitcoin
b) change the hashing algorithm
c) remove POW entirely, i.e. fade it out
d) change the rule set to make it impossible to enforce a blockchain reorganization through POW
e) ?

a) defeats the purpose of ppcoin, since it causes the energy consumption of the network to be equivalent to bitcoin. b) is an option, but the hashing algorithm has to be well chosen. Also we will likely see the same technological progression as with bitcoin, going from cpu, gpus, fpgas to asics eventually. c) is an option, but would require to revise the inflation policy entirely. d) is the most interesting option, and would require to tweak the ppcoin consensus model. Ideally an entity would require BOTH, a significant hashing power AND stake generation power to perform a successful double spent attack, instead of only one. However, using stake as a means to perform a double spent attack has network trust issues as a fallout and thus has a higher associated cost - an aspect entirely missing for POW attackers.

Conclusion
==========

The consensus model in ppcoin using a POW/POS hybrid scheme allows an entity to use either component to perform a double spent attack. This is a longterm liability for ppcoin, because it allows bitcoin miners to have a unique advantage when committing attacks in the ppcoin network. Ideally a hybrid scheme requires significant investments in both components, POW and POS, at the same time, to become a thread to the network, raising the economic cost significantly. If so, a bitcoin miner would have to acquire significant stake first, which exposes himself to economic risk.

It is worth noting that this is not a unique problem of ppcoin. All blockchains which use the POW system of bitcoin (e.g. freicoin) suffer from the same exposure. However, the hybrid POW/POS may allow for a rule set which forces an entity to have a disproportionate cost when attempting a blockchain reorganization.

It is also worth noting that checkpointing currently prevents this exposure from being exploited.

@Sunny: This is an invitation to improve the ppcoin consensus model in the long run. I'd appreciate if you could share your ideas on fixing the issue in the open. Especially since it may require a revision of the consensus model, which is not just an algorithmic tweak. Also, please correct me if I am wrong - I may have overlooked something in my analysis.
7  Alternate cryptocurrencies / Altcoin Discussion / ppcoin market crash on: January 15, 2013, 09:19:24 AM
It would probably help with the trust in the currency if the proposed changes in the code (https://bitcointalk.org/index.php?topic=114994.msg1454860#msg1454860) are reviewable and discussed publicly, before they come online.

By keeping the development a secret you loose trust - short term and long term. The current drop in ppc price is likely not a risk mitigation by investors, but a dump. That also explains the wide gap between bids and asks.
8  Alternate cryptocurrencies / Altcoin Discussion / ppcoin - stake burn-through vulnerability on: December 21, 2012, 10:00:12 AM
This is a result of a recent security analysis I performed for ppcoin. Comments are appreciated.

Abstract
========

A vulnerability in the POS scheme implemented by ppcoin is presented, where an attacker can increase the POS generating capacity of available stake by performing an exhaustive search for the POS target equation.

Introduction
============

The security model of ppcoin is based on a hybrid proof of work/stake (POW/POS) design, where the majority of new coins are generated through POW and the long-term network security is facilitated through POS generated blocks. Using the generated coins itself in the mining process has the obvious benefit of avoiding the consumption of a physical resource, e.g. electricity, in securing the network. The premise of POS is that by using existing coins as stake in competing for the generation of valid blocks, no entity can manipulate the blockchain growth in their favor, e.g. by performing double spending attacks, if the stake is sufficiently decentralized. However, the POS implementation of ppcoin has a vulnerability, which allows an entity with a moderately small amount of stake to temporarily gain control over blockchain growth, and thus perform double spending attacks. This is facilitated by "burning" the stake as fast as possible, which is possible by increasing the sampling rate at which each stake is tested against permutations of the seed constants in the POS generation process. As a consequence, an attacker only has to gain as much stake and computational power to outpace the network for a limited number of blocks, for the attack to go through. The speedup gained by burning stake as fast as possible can be significant (>1000), because the default sampling rate provided by standard client is low. Since the amount of stake required for exploiting this vulnerability is negligible, the premise of stake being a force to keep miners benevolent does not apply to this kind of attacker.

Discussion
==========

The hashing algorithm for POS tests each unspent output for the following target condition (wallet.cpp,1263/1264)

CoinDays*TargetPerCoinDay >= Hash(Difficulty + InputStakeBlockTimestamp + InputStakeTXByteOffset + InputStakeTimestamp + InputStakeTransactionOutputNumber + CoinstakeTimestamp)

The default client tests the result of this condition at a rate of 1 to 5 per second.
The left side of this equation depends on the amount and the age of the used stake (CoinDays) and the POS difficulty of the network (TargetPerCoinDay). The network difficulty is adjusted so as to keep the number of generated POS blocks per hour constant with a running average (logic defined in function GetNextTargetRequired() ). The right side of the equation is deterministic with a finite search space: The difficulty is a fixed number and only depends on the current height of the blockchain, the InputStakeBlockTimestamp, InputStakeTXByteOffset, InputStakeTimestamp and InputStakeTransactionOutputNumber are determined by the unspent stake output to be consumed and the CoinstakeTimestamp is taken from a 2 hour window from current to past time, with a granularity in seconds (thus about 7200 choices possible).

The likelihood of generating a POS block is defined by the proportions of the left and right side of the above equation and the number of trials:
P(success)=trials*P(left>=right,trial)
(approximation for P(left>=right,trial)<<1)

Thus one can directly see that increasing the #trials increases the overall capacity of a stake output to yield a valid POS block, given that the input for the right side of the target condition is variable. The reason to include variable input parameters is to prevent pre-computation attacks, where an attacker pre-computes valid POS blocks for highly predictable input parameters for the right side of the target equation. Including the Difficulty parameter in the target equation makes the computation dependent upon the current state of the network, and requires an attacker to have the required computational resources online at the time of the attack or compute a wide variety of difficulty pathways in advance. The purpose of the CoinstakeTimestamp parameter seems to be to constrain the validity of the input for the hash equation to a specific time regime, thus furthering the need for online computational resources.

Thus the POS scheme seems to be exposed to a dilemma: While the right hand side of the target equation needs to be variable and moderately unpredictable (to prevent pre-computation attacks), the increase in variability increases the benefit of using computational resources to extend the POS generating capacity of a stake by maximizing the #trials. The effectiveness of burning stake by maximizing the sampling rate is shown in the Appendix A.

Conclusion
=======

While this analysis discusses the effect of an exhaustive search on the target equation, the possibility for advanced pre-computation attacks is yet to be determined. At its current incarnation, the target equation is highly predictable which may allow an attacker to boost their POS generating capacity to ridiculous lengths, given enough computational resources. Under these conditions the amount of stake only determines the maximum time the attack can be sustained. However, many attacks, e.g. double spend attacks require only temporary control over blockchain growth.

What matters in the end is the effect of competition. I.e. if all major stake holders perform the same aggressive sampling strategies for generating POS blocks, the possibility to outpace the network is nullified. However, this degrades POS to POW, because suddenly finding valid POS blocks "fast" is a computational problem. This renders the POS implementation pointless.

Appendix A
=======

stats:

sampling rate: 200 trials per second per unspent output
stake: ~ 220k
65 consecutive blocks.
total time: 338 seconds
average time per block : 5.2 seconds


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    {
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        "category" : "immature",
        "amount" : 462.64000000,
        "confirmations" : 7,
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]
9  Economy / Lending / ASICMINER secured loan request on: November 11, 2012, 09:13:48 PM
I'd like to restructure my portfolio for which I need $2800 on short notice. Unfortunately the GLBSE meltdown makes it difficult to easily liquidate a proportional fraction in asicminer shares. I am thus looking for one or two people to give me a $2800 loan with 2500 ASICMINER shares as collateral (~2800 USD / 11 USD/BTC / 0.1 BTC/share). The loan should be denominated in USD. However, I can pay the debt in BTC (using the current exchange rate). I'd also consider selling ASICMINER shares, but that should be at a higher price point. Please PM me your offers. Interest rates should be below 12% APR, i.e. 1% per month. Otherwise I could just go to a bank.

The reason for keeping the number of loaners low is that I don't want friedcat (one of the owners of ASICMINER) to have to handle to many claim changes in the event of me being hit by a bus. Thus please only offers for > $1000. Please know that I will honor the debt irrespective of the state of the collateral.
10  Bitcoin / Bitcoin Technical Support / Wallet Brute Force Cracker on: October 07, 2012, 05:06:45 PM
Hi,

is there an open-source wallet brute force cracker, which takes the input from a wordlist file and reports the successful passphrase?
It is not uncommon for people to lose part of their passphrase and they need to test a few 10000 variations.

A feasible solution right now is to use the RPC interface and wrap it in a script, this way I achieve about 10 trial keys per second. So if the wordlist is < 100,000 keys, a full scan should be completed in about 3-4 hours. (since the procedure is embarrassingly parallel you can easily increase the cracking speed, e.g. 1000 instances should give you about 25 million trial keys / hour)

procedure:
0) create a wordlist with one of the major password cracking tools (e.g. john the ripper)
1) run bitcoind as a server with RPC active
2) adjust the following python script to your operating system and environment (link:http://ubuntuone.com/7XJaHf4OH4Ak91DUGhscvG):
Code:
import subprocess
import sys

wordfile=open(sys.argv[1],"r")
logfile=open(sys.argv[2],"a")

for l in wordfile:
 sys.stdout.write("trying %s" % l)
 w=l.strip()
 p=subprocess.Popen(['./bitcoind','walletpassphrase',w,"1"],stdout=subprocess.PIPE,stderr=subprocess.STDOUT)
 s=p.communicate()[0]
 if ("incorrect" in s):
  logfile.write("%s: incorrect\n" % (w))
 elif ("unlocked" in s):
  logfile.write("%s: unlocked\n" % (w))
 else:
  logfile.write("%s: likely passphrase\n" % (w))
  print "success!"
  print "likely passphrase: %s" % (w)
  break

logfile.close()
3) run the script local to your bitcoin directory:
Code:
python crack.py wordlist.txt log.txt

I'd appreciate if people could extend this thread by explicit instructions for their specific operating system and environment.
11  Alternate cryptocurrencies / Altcoin Discussion / ppcoin offline coinstake creation on: October 05, 2012, 05:12:47 PM
this is a reminder that we need an air gaped solution to create coinstake. In the long run it's a liability to have the private keys on the validation nodes.

From my current understanding this would work:

1) offline: generate coinstake transaction candidates (CSTC) by sequentially changing the time stamp from now up to a future time (e.g. a year from now)  and save them on disk.

2) transfer

3) online: ppcoind reads CSTCs from file and filters them by applying a sliding window over the timestamp. If a CSTC meets the target specs it gets consumed and the corresponding stake cannot longer be used.

rinse and repeat every 1-2 months or so (to bring consumed stake back online).

Ideally this would be a feature of ppcoin in the future, but maybe someone already hacked something like this? If so please post here.
12  Bitcoin / Bitcoin Discussion / Cryptocurrency Journal (edit: Financial Cryptography) on: October 03, 2012, 02:12:26 AM
Hi,

are there any scientific journals dedicated to cryptocurrencies?

If not, maybe the bitcoin foundation can establish it?

Opinions?
13  Alternate cryptocurrencies / Altcoin Discussion / ppcoin transaction fees on: October 01, 2012, 01:26:14 PM
In ppcoin transaction fees are not redistributed to the miners, but instead "destroyed". This destruction is compensated by the influx of new money, either through POS or POW blocks. This is a drastic change of the incentive structure for validation nodes and may become a problem, as explained in the following:

In bitcoin, the transaction fee acts as an incentive for miners to include transactions. The first goal of transaction fees is to accomplish spam prevention. The second, more complex aspect is the incentive for validation nodes: By providing a transaction fee, a validation node can earn money by including the transaction in the next block. If the block gets crowded, the validation node can prioritize transactions based transaction fees. (However, that incentive structure posses its own problems, since nodes may have an incentive to WITHHOLD transactions with large fees from other nodes)

In contrast in ppcoin, there is no direct incentive to include transactions into blocks. Thus the mechanism to determine transaction priority may vary dramatically throughout validation nodes. A person creating a transaction has thus NO DIRECT MEANS to influence the priority of the transaction. This can become a problem if the transaction limit in ppcoin is reached.

This is a QOS (quality of service) problem for transactions in the ppcoin network. Users have to be able to increase the priority of their transactions by providing monetary incentive.
14  Bitcoin / Bitcoin Discussion / Bitcoin becomes a transport protocol (?) on: September 20, 2012, 02:49:12 AM
With some of the recent developments I see across the forum, I begin to wonder what the fate of bitcoin holds. It seems to be that people start putting layers on top of the bitcoin transaction protocol to achieve additional features and functionalities.

To name a few:
- Colored BTC: https://bitcointalk.org/index.php?topic=106373.0
- Smart Property: https://bitcointalk.org/index.php?topic=41550.0
- Assurance Contracts: https://bitcointalk.org/index.php?topic=110402.msg1201508#msg1201508

It looks to me that cryptocurrency is the http of the world wide web. However, unlike http, traffic in the bitcoin network comes at a cost. The reason is that proof-able and irreversible transactions cost money (and energy).

Thus the more services build on top of bitcoin, the more crowded the network becomes and ultimately the cost rises. It will be interesting to see how that equilibrates, that is : what services can "afford" to use bitcoin for irreversible transactions?

Please list here the promising new services which use bitcoin as a transport layer if you know any.
15  Alternate cryptocurrencies / Altcoin Discussion / PPcoin: POW difficulty reward relationship on: September 17, 2012, 12:21:31 AM
I just realized an interesting conclusion based on the proof-of-work reward mechanism implemented in PPCoin.

here is the relevant part from the source
Code:
    static const int64 MAX_MINT_PROOF_OF_WORK = 9999 * COIN;
    CBigNum bnSubsidyLimit = MAX_MINT_PROOF_OF_WORK;

    // ppcoin: subsidy is cut in half every 16x multiply of difficulty
    // A reasonably continuous curve is used to avoid shock to market
    // (nSubsidyLimit / nSubsidy) ** 4 == bnProofOfWorkLimit / bnTarget
    CBigNum bnLowerBound = CENT;
    CBigNum bnUpperBound = bnSubsidyLimit;

    while (bnLowerBound + CENT <= bnUpperBound)
    {
        // changes bnLowerBound and bnUpperBound to converge against bnMidValue
        // exists when bnUpperBound is within 1 CENT of bnLowerBound
    }

    int64 nSubsidy = bnUpperBound.getuint64();
    nSubsidy = (nSubsidy / CENT) * CENT;


which translates into this behavior: (difficulty, POWreward)
10   5,622
100   3,161
1K   1,778
10K   999.9
100K   562
1M   316
10M   177
100M   99.99
1G      56
10G      31
100G   17

Which means that inflation is high when the difficulty is low. Thus, people with huge STAKES have an incentive to keep the POW difficulty high! Why? Because a high inflation rate devalues stake (more stake available -> proof of stake difficulty rises).

However, every 10-fold decrease in subsidy is accompanied with a 10000-fold increase in difficulty. Thus people who accumulate stake early on, CAN NOT easily decrease the POW reward.
With current difficulty at 10K, the expected supply is 51M/year. If difficulty goes up 100-fold the supply drops to 16M/year.
However, on the other side, keeping the reward below a certain level (and thus prevent high inflation rates) is also cheaper. If you own 0.01% of the mining power (1/10000) you can limit the MAXIMUM supply of new coins to 510M/year!

conclusion:
=======
The difficulty dependent POW reward scheme introduces some very interesting incentives, especially for stake holders. Its steep relationship suggests that limiting the money supply is CHEAP, but throttling the money supply is EXPENSIVE, causing the expected inflation rate to stay within a healthy region. I don't know whether this was the original intent when the reward mechanism was designed, but it's certainly a feature.
16  Alternate cryptocurrencies / Altcoin Discussion / PPCoin: stake reward logic (GetProofOfStakeReward) on: September 12, 2012, 11:52:34 PM
I am currently digging through the ppcoin source code to understand the reward mechanism.

Stake rewards are calculated based on the following equation (code below)


CENT=10000;
int64 nSubsidy = nCoinAge * 33 / (365 * 33 + Cool * CENT;


Thus a CoinAge of 30000 (1000PPC at 30 days) provides a reward of about 0.8PPC (which corresponds to about 0.08% interest per month or about 1% per year)

Questions:
1) what the purpose of the 33?
2) Is there another limit to the money generation I overlooked? Right now it looks like PPCoin is inflationary in nature (1% per year).
3) What is the rationale for the choice for rewards? Why 1% and not 0.5% return on stake per year?

Thanks to whomever has answers.

Code:
// ppcoin: miner's coin stake is rewarded based on coin age spent (coin-days)
int64 GetProofOfStakeReward(int64 nCoinAge)
{
    static int64 nRewardCoinYear = CENT;  // creation amount per coin-year
    int64 nSubsidy = nCoinAge * 33 / (365 * 33 + 8) * nRewardCoinYear;
    if (fDebug && GetBoolArg("-printcreation"))
        printf("GetProofOfStakeReward(): create=%s nCoinAge=%"PRI64d"\n", FormatMoney(nSubsidy).c_str(), nCoinAge);
    return nSubsidy;
}
17  Other / Off-topic / Possible impacts of ASIC mining and hypothetical scenarios on: September 02, 2012, 07:30:48 PM
This thread is a spin-off from:
https://bitcointalk.org/index.php?topic=99497.msg1154935#msg1154935

Please use it to discuss the implications of the emerging field of ASIC mining and the role of ASIC hardware companies. Mentioned topics are interest of conflict between using the chips and selling them, secret algorithms and back-doors.

Enjoy!
18  Economy / Securities / Unrealistic orders on GLBSE on: August 31, 2012, 04:02:55 PM
Look e.g. at https://glbse.com/asset/view/ASICMINER

I wonder what the purpose is of a sell order for 1 share @ 999,999,999 bitcoin.
Obviously its not gonna get filled for more than one reason. (Unless GLBSE introduces the concept of fractional shares).

Also if the market crashes someone buys at 0.
19  Economy / Speculation / Long-Term sub-exponential, short term bubbles on: August 02, 2012, 07:20:47 PM
f(x)=0.05*exp(b*(x**c))
Final set of parameters            Asymptotic Standard Error
=======================            ==========================

b               = 0.182109         +/- 0.0119       (6.536%)
c               = 0.499584         +/- 0.01005      (2.012%)

based on that estimate we're gonna have a "base value" of $20 in a year from now. Variation due to bubbles excluded.

anyone disagreeing?

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