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1  Economy / Trading Discussion / MOVED: 500 BTC for sale on: December 05, 2017, 08:48:56 PM
This topic has been moved to  Currency Exchange-Child board for better answers.
2  Economy / Currency exchange / 500 BTC for sale on: December 05, 2017, 11:10:51 AM
Good afternoon, ladies and gentlemen!
My friend from Moscow wants to make a deal to sell 500BTC for cash (cash may be in any fiat currency).

Bank transfer is possible in euros or dollars.

Exchange rate Bitstamp + 1.5%

We are looking for buyers.

Also we need advice on how to conduct such a transaction in the best possible way.

If someone has constructive suggestions, please contact me via PM.

The proposal is active due today and tomorrow.

Looking forward to hear from you.

In the future there will be more offers for sale in large volumes. For real buyers, please contact me via PM.

3  Economy / Currency exchange / anyway want paypal for BTC ? on: November 01, 2017, 01:57:47 AM
I have 190$ paypal which i can not withdraw cause paypal did not allow my country to withdraw funds. so if anyone interested please let me know
you can hold BTC money with escrow for 1 week just to be sure that funds from secure source and not stolen.
4  Bitcoin / Development & Technical Discussion / What is normal outbound traffic for the Bitcoin-qt wallet? on: April 18, 2014, 09:07:07 PM
I have a Bitcoin-qt client running that is doing 6gb of outbound traffic per day.

This isn't even an open wallet (i.e. the inbound ports are firewalled) - so this is just outbound traffic initiated by the wallet itself. I take it when the wallet connects to a peer, the peer then can in turn retrieve blocks from the wallet, which is where the traffic comes from.

Is 6gb/day normal usage though?

If so, is there a way I can trickle it down?

I want to support the BitCoin network, but 6gb a day is a bit excessive (I have to pay for all outbound traffic - this ends up being $100's per year).
5  Bitcoin / Development & Technical Discussion / Effect of orphan blocks on bitcoin wallet API on: March 22, 2014, 05:17:29 PM
When a couple of blocks are orphaned, I assume the following will happen.

Can someone verify this is correct? (Kind'a difficult to test).

Let's say there is a two-block fork:

   291871  291871
     ^       ^        
     |       |
   291870  291870
     ^    ^
     |   /

And the bitcoin wallet went down the right-hand-side (incorrect) fork until 291872, and then jumped back. It's behavior would be:

a) Prior to orphaning, getblockhash returns one set of hashes for the blocks at that height:

  getblockhash 291869
  getblockhash 291870
  getblockhash 291871

b) Once the orphan chain is detected and resolved, those block heights values will now map to different hashes. E.g.:

  getblockhash 291869
  00000000000000004674e91dd6efeac7255d1de13fadc55261241dcb6d8397b5  // still the same
  getblockhash 291870
  0000000000000000419cfd8ed2fc0e919c1cdb20f4fb009a4a19fdd7a20d5961 // new hash
  getblockhash 291871
  0000000000000000a2185dc7779f93831925909cb489e8e7a9d007beee0cc619  // new hash

and after this point, life will be good again. getblockhash 291872 will return the new valid hash from the main chain etc.

c) The previous hashes will still be usable to retrieve the orphaned block information directly (e.g. through getblock), but getblockhash will return a different block at that height.

d) Since the wallet jumped back to the main chain, there is no other way to enumerate these orphaned chains again unless you kept track of it while it was happening and scribbled away their hashes.

6  Bitcoin / Development & Technical Discussion / Base58 without bigint? on: March 21, 2014, 10:21:43 PM
Does anybody have an snippet or theoretical algorithm available that can encode a byte array to Base58 without using BitInt? (Instead using chunks or some other technique).

I can do this in my sleep for Base64, but Base58 makes my head hurt.

I created a blockchain scanner, and it's spending 70% of it's life now in the Base58 address conversion (Using BigInt from BouncyCastle). Argh.

- Deon
7  Bitcoin / Development & Technical Discussion / I don't think 'Pi' is a valid public key... on: March 16, 2014, 11:32:18 AM
The following block:

Has a OP_CHECKSIG on n=1 for:
0431415926535897932384626433832795028841971693993751058209749445923078164062862 089986280348253421170679821480865132823066470938446

Taking out the '04' uncompressed form marker, and you've got yourself pi to 128 digits. (Sort'a. That's really a hex number. Whatever.)

Not surprisingly, it fails the elliptical curve equation (and had me swearing at Bouncy Castle all night).

How did this make it into the blockchain?
8  Bitcoin / Bitcoin Discussion / Handling of a duplicate transaction across 2 blocks on: March 16, 2014, 05:25:32 AM
How does the following happen?

This same transaction occurs as the coinbase transaction for both block 91812 and 91842.

It hasn't been spent, but it's obviously not spendable from both blocks. So one of the mined blocks actually did not get any reward.

I can imagine 1 miner screwing that up but I would have thought additional confirming miners would have thrown out the duplicate transaction, no?

Is this a common occurrence that we need to take into account, or is it a weird anomaly?

Obviously coded around that, by allowing the same transaction to be displayed in 2 blocks.
9  Bitcoin / Development & Technical Discussion / Why does some coinbase scripts not check public key hash? on: March 14, 2014, 06:52:30 PM
The answer is probably staring me right in the face, but I'll blame it on a late night...

I notice that in some cases the Coinbase vout will require a full 'OP_DUP OP_HASH160 <public-key-hash> OP_EQUALVERIFY OP_CHECKSIG' check:


However, in other cases the Coinbase vout will just require a sig check (and a clear public key?):
<public-key> OP_CHECKSIG


What makes the difference? (i.e. is it a different mining client? Pool software vs. solo miner vs. version etc.)

10  Other / CPU/GPU Bitcoin mining hardware / How to manage an ant army? on: March 07, 2014, 07:45:57 PM
A friend of mine (cough cough) may or may not have a whole bunch of Antminers S1's.

What is the best way to manage them?  (Hypothetically of course).

If you want to e.g. move all of them to a different pool, it's an absolute nightmare to manage via the UI, logging into each miner, changing the settings etc. Same if you want to see which ones have x'd out ASIC's and need to be rebooted.

Was fun at first, but no.

Is there some sort of SNMP like management plugin available for micro-farms consisting of small miners like these?
11  Bitcoin / Development & Technical Discussion / Do you know the Bitcoin wallet code? [btc] 0.2 for 1 hour of your time on: March 04, 2014, 10:43:34 PM
I'm busy learning the Bitcoin wallet code, and have a bunch of questions. Searching online and through forums is taking forever, and I don't want to continue spending days for what I'm sure I can learn in an hour of dedicated time by an expert.

If you consider yourself an expert in the Bitcoin wallet source code, and can talk with ease on areas of:

* Transaction management
* Database interaction
* Key storage

and have good conversational English, I have an offer for you:

I offer BTC 0.2 or $125 via Paypal (your choice) to have a Skype chat for 1 hour on the above subjects. Either voice chat or messaging is fine.

I have a 20 years C / C++ background, so if you're trying to B/S me, I'll know and you won't get the full award.

And don't worry, I'm not creating another coin.

PM me your background information and point to things you've worked on (e.g. other coins), and I'll select the best candidate.

Proof of funds:

12  Alternate cryptocurrencies / Altcoin Discussion / We need more SHA-256 altcoins on: March 04, 2014, 07:33:53 PM
If you're creating another coin, please consider making it a (good) SHA-256 coin.

The new SHA-256 altcoins have the potential to take away a significant amount of hashing power from BitCoin. This is a good thing for all miners, as well as for the planet.

Maybe someone can come up with a 'RecycleCoin'?
13  Alternate cryptocurrencies / Mining (Altcoins) / What is a good reject rate during rapid blocks? on: February 24, 2014, 08:04:31 AM
I am solo mining some SHA256 coins that sometimes changes blocks rapidly (<10 seconds). I have a pretty high reject rate (20%) which always seems to do with finding a block within a few seconds after a switch.

Even with the 20% reject rate, I'm still doing better on average than I would do in a pool though.  Is 20% rejects just expected in this case? Is that what the pools are also facing? And most importantly - is there anything I can do to make it better?

* Mining gear runs at ~420gh/s
* Connecting over 100mps to do GetWork against a -q wallet.
* Internet connection is 60mbps up, 10mbps down.
* Queue size is 30. If I make it lower than 30, I see a lot of "Pool x not providing work fast enough". If I make it higher I can see it submits blocks 5 or 10 seconds after change. Not good.

 (5s):452.2G (avg):437.7Gh/s | A:977635  R:250404  HW:2493  WU:7946.5/m                                                        
 ST: 27  SS: 0  NB: 231  LW: 340449  GF: 65  RF: 1                                                                              
 Connected to diff 20.5K with LP as user xxxx (cgminer is confused with LP flag. I have a failover pool that uses LP. Active pool doesn't have Longpoll.)
 Block: 11569b68...  Diff:49.5K  Started: [23:56:42]  Best share: 971K                                                        
 HFA 0: 424.6G/438.0Gh/s | A:977635 R:250404 HW:2502 WU:7937.3/m                            
 [2014-02-21 23:46:44] Pool 0 not providing work fast enough    
 [2014-02-23 23:46:47] Network diff set to 49.5K                                                                                
 [2014-02-23 23:46:47] New block detected on network before longpoll                                                            
 [2014-02-23 23:46:53] New block detected on network before longpoll                                                            
 [2014-02-23 23:46:55] Found block for pool 0!                                                                                  
 [2014-02-23 23:46:55] Pool 0 stale share detected, submitting as user requested                                                
 [2014-02-23 23:46:55] Rejected 11471acf Diff 971K/49527 BLOCK! HFA 0 pool 0                                                    
 [2014-02-23 23:46:56] New block detected on network before longpoll                                                            
 [2014-02-23 23:46:56] Pool 0 not providing work fast enough                                                                    
14  Alternate cryptocurrencies / Marketplace (Altcoins) / For sale - Mazacoin (MZC) on: February 22, 2014, 07:57:22 PM
Selling Mazacoin @ 10000 for BTC 0.1

Ping me if you're interested.
15  Economy / Service Discussion / Mt Gox's new office on: February 20, 2014, 03:49:01 PM
I'm generally the last person to spot things, so this may be very old news, but I just noticed that Mt Gox is saying that they:
"had to relocate MtGox to our previous office building in Shibuya (details can be found here"

That office address is:
MtGox Co.,Ltd.
Cerulean Tower 15F
26­1 Sakuragaoka­cho
150­8512 Shibuya Tokyo

However, Cerulean Tower floor 15 is not a general office. It belongs to a company called "The Executive Centre", which is a business that offers virtual offices.


A virtual office provides your business with the corporate image and business infrastructure of a multinational company without the cost. Your business will get a prestigious business address and a designated local phone number with a receptionist answering your calls in your company name. Professionally trained secretarial staff will manage your correspondence, and can provide additional administrative and support services as you need them.

If you go to the Executive Centre link above, and click on the Virtual Offices link above, then click on Locations, you will see under Tokyo they have the Shibuya Cerulean Tower, which when clicked on, reveals that they have floor 15 - the new Mt Gox address.

Level 15, Cerulean Tower, 26-1 Sakuragaoka-cho, Shibuya-ku, Tokyo, Japan 150-8512

So I'm just curious how Mt Gox plans to "relocate" into what is essentially a phoneline.
16  Economy / Marketplace / 3x 12.7 GH/S Block Erupter Blades for $129 each on: February 12, 2014, 07:18:47 AM
I have 3 v1. blades for sale on eBay if anybody is interested:

$129 each + $12 shipping.

update: gone
17  Alternate cryptocurrencies / Mining (Altcoins) / Alienware fan control based on GPU temperature? on: January 29, 2014, 10:56:37 PM
Is there a miner (or other software) that will tie the fan speed of an Alienware Aurora-R4 to the temperature (or fan speed) of the GPU?

When I mine, my PCIe fan needs to sometimes blow at a higher rate for the GPU's to stay cool.

However, they're very noisy (much more so than the GPU fan), so I don't want it to run at > 70% all day.

cgminer does a great job when it comes to fan & speed control of the GPU itself, but it doesn't control my PCI fans. Is there a way to make it do that?

Alienware has the Alienware Comand Center that can dynamically adjust fans, but its useless. The internal temperature sensors always show 25 degrees C (it's a well known issue with the Alienware Aurora), and it doesn't seem to be able to look at the GPU.
18  Alternate cryptocurrencies / Altcoin Discussion / What is the unit of difficulty published by CoinWarz?? on: January 28, 2014, 02:30:31 AM
I give up. Cry

CoinWarz is publishing a unit of difficulty that I cannot make sense out of.

AlphaCoin's "Current Difficulty" is listed as: 0.589 of some or other Huh unit (let's call that unit fluffybunnies).

cgminer tells me that the AlphaCoin difficulty is: 44.8kH/s. It's been that for a while, so it's a good time to compare now.

I know there are things I can look at, like the 50 block award or 30 seconds/block, but no matter what formula I'm guessing at I can't seem to convert 44.8kH/s into 0.589 fluffybunnies.

This isn't specific to AlphaCoin. I similarly can't convert FastCoin's current 46.1kH/s into its 0.7037 fluffybunnies listed on CoinWarz.

What is this supposed to be?

19  Alternate cryptocurrencies / Mining (Altcoins) / Unethical treatment by Newegg on: January 27, 2014, 06:04:45 PM
You wouldn't think that Newegg would treat you the same way that some kid in a basement on a far away continent does, but here they go:

I ordered and paid for a R9 290x from Newegg yesterday for $550 with overnight shipping. This morning Newegg decided to void my order without a specific explanation, and recommended that I should check with my Credit Card company for a wrong address (Uhh... I used Paypal).

Immediately after the email I came back to the site and see that the same card is now listed at $650.

So they basically just went and cancelled my order because they decided that can gouge other customers for an extra $100.

Yes, I know that $550 is on the low side for an R9 at this point, but that doesn't mean screwing over open orders from existing customers.

Just venting.   Angry

AltCoin: Changing perfectly legitimate companies into common thugs.
20  Bitcoin / Mining speculation / Dollars spent in increasing network speed on: November 07, 2013, 11:46:05 PM
So I know that conventional graphs has us at 7.5 billion difficulty (58000 ph/s) in a year.

However, there is an aspect to consider. It costs real money to increase the network capacity, while the amount of BTC/month that can be earned through the entire network is approximately constant.

So currently, there is: 25 btc x 10 times per hour = 180'000 btc per month up for grab = $54 million (at $300) per month.

So let's see what month-by-month doubling costs. Starting with a basis of 4phs at beginning of November, and let's try and double that each month.

Nov: +4phs = $44m (KNC at $11)
Dec: +8phs = $40m (BitMine / HashFast at $5)
Jan: +16phs = $56m (CoinTerra at $3.50)
Feb: +32phs = $96m (CoinTerra at $3)
Mar: +64phs = $128m (BlackArrow at $2)

After this point, there is a very real prohibitive cost to double the network. Getting 50'000 people to buy $100 worth of ASIC Blocks is one thing. Getting 10 million people to spend $100 with no hope of breaking even is something else. The amount of actual money it will take to grow becomes too large for the growth to keep being irrational.

So one of 3 things have to give:

1) Manufacturers will have to start cutting mining hardware prices by 50% per month. So that means a 2TB miner selling a year from now for $25 (1.25c /ghash). I don't see that happening - laws of physics and all that.
2) The price of Bitcoin has to double each month. So $76'800 / BTC 1 year from now. Fun.
3) The network difficulty has to taper off significantly starting after March.

My bet is on #3.
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