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281  Bitcoin / Mycelium / Re: Mycelium Bitcoin Wallet on: April 23, 2014, 08:42:23 AM
The APK in the play store and on the web-site is the same, and signed under the same certificate.

How long before the version available from the Mycelium website gets updated to the same version on Google Play?
Currently v1.2.0 on the website, v1.2.1 on Google Play:
282  Economy / Trading Discussion / Re: Tips for local transactions on: April 22, 2014, 08:36:21 AM
There is something that has the potential to impact local trading -- the "Replace By Fee" patch (and related "Undo" service BitUndo):

Peter Todd's recent 0-confirm double spends:


Many in-person and online cash trades are settled immediately where the buyer hands over cash after seeing a transaction from the seller to the agreed-upon Bitcoin address.  But after the cash is handed over and the two parties each go their own way, the seller has the potential to reverse the transaction.  This is because with Bitcoin, transactions with zero confirmations are not safe -- until they receive a block confirmation or three (or six, depending on the risk level).

Historically, there hasn't been much "double spending" of zero confirmation transactions, and even significantly less double spending of transactions where there was at least one confirmation.   That's because the behavior of the Bitcoin client typically used by miners only recognizes the first spend and thus attempts to double spend (e.g., via race attack) are ignored.  

However, there is a modification to the Bitcoin client that miners can use that changes things signifcantly.  This change is intended to allow a person spending Bitcoin to submit an alternate of the transaction before the original gets mined such that the original transaction is ignored and the alternate gets included in the blockchain.

So though you as a trader might see a transaction where you receive your bitcoins, the seller could then mess with that transaction sent to you such that it will never confirm.

There is very little mining capacity currently using this modified client so the chances of someone trying to do this has a low likelihood of success.  But that risk exists (as it always has) just that it is now a higher risk.

A trade using LocalBitcoins doesn't have this issue because the coins are escrowed and then released into the user's E-Wallet with LocalBitcoins (i.e., trades on LocalBitcoins don't go through the blockchain).

Mycelium now has a "Local Trader" feature in which the risk can be lessened thanks to trader history ratings as well as a unique Transaction Confidence approach in which the network is probed to discover double spend attempts and the user is warned when transactions have a higher risk of being double spent (e.g., when they rely on other zero-confirmation transactions).

Mycelium Local Trader
283  Local / Marketplace (India) / Re: WTB: gift certificate (INR) on: April 21, 2014, 08:56:20 AM
I'm looking to add 3,000 Rs again (21-Apr-2014).

How this works is,
1.) You and I agree on the rate (in BTC) for your 3,000 Rs.  [e.g., ~0.1 BTC if using today's BTC/USD of $500 on BitStamp]
2.) I provide to you my e-mail address.
3.) You buy a 3,000 Rs gift e-card from Milaap, paying with your Netbanking or with an Indian credit card.  Entering my e-mail as the gift recipient.

 -  <-- PM me for my Milaap "lender name and e-mail".

4.) You send to me your Bitcoin address for my payment
5.) I receive the e-mail, redeem the gift e-card, and send to you the bitcoins.

PM me if interested
284  Bitcoin / Bitcoin Discussion / Re: A successful DOUBLE SPEND US$10000 against OKPAY this morning. on: April 12, 2014, 05:52:18 PM
I think of a double spend as a spend with confirmation followed by another spend of the same balance.

Which is what happened in March, 2013.  If you were using the v0.8 client there was a transaction that had more than six confirmations but later the fork which pre-v0.8 clients were mining surpassed the one the v0.8 were using and that transaction became invalid.  What happened was a user noticed the fork, created a new transaction that spent the same funds, used a custom client that repeatedly broadcast the double spend attempt and eventually that new transaction got included in the pre-v0.8 blockchain fork.

So yes, a double spend of a transaction that had six or more confirmations on what was at the time the longest chain is something that has occurred.

The gist of the problem was that miners starting up with the v0.7 client had an empty memory pool and thus no knowledge of the transactions that had already confirmed in the blockchain fork mined by the v0.8 clients.  So then it simply is a race -- whichever transaction (of the two that were spending the same coin) that reached those miners first is the one that was being hashed.   For that specific weakness, there are solutions that had been discussed but not implemented as far as I know.  For instance, when the miner is shut down the unconfirmed transactions in the memory pool could be written to the filesystem and then those transactions get loaded first when the miner starts back up.   That would likely have made the result of that March 2013 fork be that no double spends had occurred.
285  Economy / Trading Discussion / Re: Tips for local transactions on: April 08, 2014, 07:27:16 PM
One resource available to those who want to do a trade locally but don't want to physically deliver the cash is a courier service.  But handing over an envelope full of cash to some kid on a bicycle might not seem to the most prudent move.

However, innovations from Uber (with Uber RUSH) and Postmates make it so that their courier / messenger services work fairly well for this task.

Here's a reddit post with a few more details on this:

And here is a forum post describing another type of courier method, one that is less expensive than an Uber RUSH type of messenger service:
286  Economy / Trading Discussion / Re: Local Delivery For Bitcoin Trades on: April 08, 2014, 05:50:30 PM
And now in Manhattan is Uber's - Uber RUSH messenger service:


What's awesome about this is that the location (tracking) is available to the sender, but that ETA/Location info can be shared with the recipient.

Additionally, by default the messenger will take a photo of the recipient's ID (Driver's license or passport).   Though for privacy reasons this might not be what the recipient wants and the sender can request that the item can be delivered to the named party with no ID verification.
287  Local / Other languages/locations / Re: Việt (Vietnamese) on: March 27, 2014, 07:02:41 AM
via Google translate:
Trao đổi Bitcoin đầu tiên của Việt Nam

There is an exchange now in Vietnam:


Press release:
Bitcoin Vietnam Co. Ltd. and Bit2C Ltd. announce cooperation for Vietnam’s first live trading Bitcoin exchange
 - (Browser friendly PDF viewer)

288  Local / Other languages/locations / Re: - Kenya/Africa Bitcoin portal on: March 25, 2014, 07:51:25 PM
Can you try after deleting any cookies?

I was using a new (clean) instance of Chrome, Incognito mode -- so there were no prior cookies.

I solved my problem by resetting the password and using that.  I feel confident I didn't have the wrong password before because no warning (showing how many more attempts before my account gets locked) appeared on each login attempt.

So whatever it was, I cannot reproduce it now.
289  Local / Other languages/locations / Re: - Kenya/Africa Bitcoin portal on: March 22, 2014, 02:55:25 PM
hi weex,

I'm having trouble logging in.   I don't see an error message, but submit on the user login just reloads the page without authenticating me (says "Hello There, Guest!").   I've tried with both my e-mail address as username, and with a username as well.  Both behave the same way.
290  Bitcoin / Meetups / Bitcoin Kenya Meetup (Nairobi) on: March 06, 2014, 09:34:13 PM
The next Bitcoin Kenya meetup is Friday, March 7th - 5:30 pm to 7:30 pm.

Pete's Cafe and Burrito Haven
Ground Floor, Bishop Magua House, Ngong Rd., Nairobi
(Ground level of the building where iHub is located).

Special guest: Tomer Kantor (iamsatoshi), who will be filming the meetup, so don't be late.

Bitcoin startups in Kenya include:


and a number of merchants and charitable organizations now accept Bitcoin payments / donations:
Give Directly
The Water Project
Wageni Technologies

Kenya presents a unique opportunity for Bitcoin in that well over half the population is already comfortable storing value "on their phones" and using that value to transfer amounts small and large to peers, or for use in bill payment or even retail purchases.    Kenya is one of the few place where a measurable percent of the country's GDP passes through the mobile payments network -- and Kenya leads all other areas with about a third of the GDP's value traversing the M-PESA and Airtel mobile payment networks.   Though M-PESA serves the market relatively well today, its users continue to suffer from the payment network's availability and performance issues and the network's operator faces renewed regulatory and other external pressures such that a gap for Bitcoin to fill exists now.

Here's an example -- Airtel mobile money woes.
291  Economy / Service Discussion / Re: what the hell are crypto stocks? on: March 01, 2014, 07:52:32 PM
I'm just trying to understand how cryptostocks work, as the website sure doesn't seem to explain much.

This is an old post (refers to GLBSE, a "cryptostocks predecessor") but the message is the same:

Investors seem to proceed with the belief that these “asset” listings closely resemble the concept of stocks or other security investments made in the regulated world.  We might blame Kickstarter for that.

Kickstarter in its initial form is a platform that simply allows a donation towards a project where the donation earns some type of reward.  Without there being equity there need not be the concept of a corporation or LLC as issuer.  Equity markets are not equity markets without the concept of a corporation or LLC where ownership can be shared by its equity investors.

Without this concept of a corporate entity or LLC there is then little parallel between an asset listed with GLBSE and a company that trades on a regulated exchange.  But when a GLBSE “asset” fails financially or the issuer defrauds, some investors feel the issuer has responsibility for the capital invested into the cyber-equity.  These investors may believe that there is responsibility that extends to the real world.  Already occurring is evidence of pressure by investors being applied against individuals who had been issuers of assets where financial losses were the result.


292  Economy / Collectibles / Re: Bitcoin Specie Project sponsored by the makers of New Liberty Dollar on: February 28, 2014, 11:28:50 PM
You can get them direct from me certainly, but there are better places if you are after just a few.,, to name a few

When I look at I don't see any method for buying the Bitcoin specie.  

I do see the link for buying from Agora Commodities:

On ebay you take your chances, we've come across some fakes.

Fake silver bullion (e.g., Morgans) ... or do you mean there has actually been fake Bitcoin specie?
293  Other / Beginners & Help / Re: Redeem bitcoins of paper wallet on: February 28, 2014, 11:39:46 AM
In order to redeem it, I read in several tutorials to import the public key in my wallet.

The easiest way I've found to redeem a private key is to use the "cold storage" feature in the Mycelium wallet (Android) app. 

It's dead simple.

1.) Select Cold Storage
2.) Scan (or paste) private key
3.) Scan (or paste) a Bitcoin address (to redeem the funds to).
4.) Click send. 

Seriously, it's that simple.
294  Alternate cryptocurrencies / Altcoin Discussion / Re: Mazacoin on: February 27, 2014, 08:53:41 PM
We're mining it hard right now, turned 600 GHs on it by late afternoon.

What's protecting this (SHA256) coin from a 51% attack?   600 GH/s total is less than a single Th/s ASIC mining rig produces.  i.e., for what is essentially pocket change the coin could be either DDoS'd with a 51% or worse -- a private fork mined with intention of double spending.  Of course, there needs to be markets where this coin is traded to make a double spending 51% attack worth the effort, but the point is -- this coin (and all proof-of-work coins, including Bitcoin), are very vulnerable to a 51% attack -- especially at the critical weeks and months (or years even) after launch before sufficient mining capacity makes the attack more expensive and hopefully, not profitable.
295  Economy / Goods / Re: NEFT Vodka and Bitcoin on: February 25, 2014, 08:25:42 PM
Wow! I like it - it's design is pretty cool!  Cheesy  WHere can I buy it?

Europe -- various locations.
U.S. -- California and Las Vegas.  Scroll back to previous posts in this thread for locations.
296  Economy / Service Announcements / Re: Bets of Bitcoin - Bitcoin betting on real world events on: February 20, 2014, 12:12:39 AM
I've got .8 BTC on the line.

If that's your withdrawable balance, here's an update from another thread.

Good news.  I was able to get a withdrawal to work eventually after many, many failed attempts.
The trick was to manually paste the withdraw URL and if the form appeared attempt to withdraw.  I think I had over a dozen tries and I'm not sure which one was the successful one.  Also, I tried withdrawing a whole number (e.g., 1) for amount and that worked.  I'm now trying to withdraw the fraction but haven't yet gotten that successfully withdrawn.
297  Economy / Service Discussion / Re: Warning and Advisory about BetsofBitcoin on: February 20, 2014, 12:11:15 AM
Just wanted to warn and advise that the site BetsOfBitcoin is not closing betting statements, the effect being that your BTC is essentially locked-up, in limbo, and not available to be withdrawn. This is a shame, because the concept of BetsOfBitcoin is a good one.

Heeding to your warning, I went there and got this:

Your request can not be completed at this time. We are working hard to fix it. Please, try again later.
Your Bitcoins and data are safe and backed up regularly.

Good news.  I was able to get a withdrawal to work eventually after many, many failed attempts.
The trick was to manually paste the withdraw URL and if the form appeared attempt to withdraw.  I think I had over a dozen tries and I'm not sure which one was the successful one.  Also, I tried withdrawing a whole number (e.g., 1) for amount and that worked.  I'm now trying to withdraw the fraction but haven't yet gotten that successfully withdrawn.
298  Other / Beginners & Help / Re: on: February 19, 2014, 11:59:50 PM
For other newbies, I've been having fun over on

As a footnote to this thread, Bets of Bitcoin is not updating bets, and there are reports that the site is not functioning when requesting withdrawals.

299  Bitcoin / Bitcoin Discussion / Re: How to use fiat currencies for Bitcoin offline transactions? on: February 19, 2014, 11:48:33 PM
Has this idea progressed at all?

The idea I floated definitely has.

In Kenya, the largest note issued by their central bank is the 1,000 shilling (KES) note.  That's worth about $12.  Cash is still used widely for making purchases such as appliances, used cars, etc.  Imagine going shopping for a new large screen TV and having to carry a 3" thick stack of bills.

Then imagine being the merchant, having to carry a satchel to transport the previous day's cash sales to the bank.

This idea has potential.
300  Economy / Exchanges / Re: Official Thread on: February 19, 2014, 10:23:58 PM
In case you haven't seen it yet, here is our official press release on Litecoin:

VirtEx launches Litecoin trading

I have a concern about having my bitcoins sit at an exchange (while waiting for an opportunity to sell, such as a potential to profit from arbitrage) but am afraid that with an exchange that also deals with alt-coins that I am at risk should the exchange suffer losses due to a successful 51% attack against an alt-coin.

This concern exists even if I don't touch any alt-coins because in most jurisdictions, once I deposit my bitcoins with the exchange, I have a liability from the exchange that is no different from anyone else's liability.   Specifically, if the exchange suffers losses from a hack attack, 51% attack or any other reason, I would not be guaranteed I could get my bitcoins back.  I shared this concern in a blog post:

When Mt. Gox announced that they were coming out with Litecoin trading, I asked some questions:

But never got an answer other than a response that my "concerns will be considered".

When Kraken announced tat they were supporting alt-currencies, I asked a similar set of questions and got straight answers:

So I would like to describe four specific scenarios that I would like to know what CAVirtEx's policy is should they occur:

A.) My CAVirtEx exchange account holds only fiat and bitcoins, and I've never traded for altcoins.  Would I be exposed to any risk of loss to those funds should there be a successful 51% attack against an altcoin that CAVirtEx supports?

B.) I have a balance of an altcoin and fiat, but had none of those altcoins deposited to CAVirtEx in any block that was ultimately orphaned as the result of the 51% attack.  Would I be exposed to any risk of loss to those funds should there be a successful 51% attack against that altcoin?

C.) I had bitcoins at CAVirtEx and I traded them for an altcoin.  Following this trade the attacker released blocks that resulted in a double spend such that the that altcoins I received were from the attacker's account (i.e., an altcoin deposited with a transaction that no longer confirms or was double spent).  Following the successful 51% attack against the altcoin, do I still have my altcoins that I purchased that I can withdraw (or trade back into Bitcoins)?

D.) In my CAVirtEx account I had deposited an altcoin from a block that utimately was orphaned as the result of a successful 51% attack against the altcoin.   Before the attack I was able to trade those altcoins for bitcoins which remain in my account.    After the successful 51% attack against the altcoin, do I still have the ability to withdraw those bitcoins?
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