Hi,

I've read about and tried testing BIP38 encryption of private keys and have succeeded in creating and decrypting BIP38 keys.

I have BTC in cold storage, on pen and paper, in an envelope in a secret place that contains my key in WIF format. I also have an identical copy at a trusted family member's, in case of burglary/fire/etc.

Now, here's a hypothetical situation about encrypting my private key:

I want to create a new cold storage BTC address with BIP38 key and send my BTC to it, with a copy at my family member's house.

My question is about the length of password to use. I could use a single character ("0", or "1") to encrypt my key. This would prevent my BTC being immediately useable if it fell into the wrong hands (burglary, etc).

If it was stolen (and supposing the thief knew what Bitcoin was), is it possible to determine the length of password from the BIP38 format, or would the thief have no way of knowing and simply have to brute-force the key blindly using incremental passwords of varying length?

Obviously, I'm not going to use a "0" or a "1" as my password, but I figure a 5 or 6 character password would make the thief's life hell and give me enough time to act and shift my coins somewhere safe.

I know that decrypting BIP38 is a time consuming process on an average PC, so would anyone like to guess how much time, say, a 6 character password would buy in this situation? How many uppercase and lowercase combinations of 6 characters (plus 0-9) are there, and how much time would this allow me to save my coin?

An update on the Dymo LetraTag:

Bought one after reading a lot of good reviews on Amazon. Bought it from a high street shop.

Put brand new Duracell (4 x AA Ultra Plus, or something) in and every time I went to make a print the "battery low" warning would come on. I perservered and printed out my keys, even trying some other brand new Duracell AA standard batteries and still the "battery low" warning.

I wasn't happy with this and took it back for an exchange, thinking that the unit I had was dodgy. The replacement did exactly the same.

So, I've given up on the LetraTag, got my money back, and will stick to hand writing BTC keys in future. I considered a Brother P-Touch model but they are too expensive and the cartridges are also pricey.

I bought a LetraTag yesterday for this very purpose. I guess I'll check on the print every year to see if it's starting to fade and reprint if it is.

Better than my handwriting, anyway.

Is a Dymo LetraTag a good idea for printing out private cold storage keys and then sticking them into an envelope? Once the batteries are removed the printer memory is wiped, right?

I've asked this question before but no-one answered.

Do you think the thermal print will fade within, say 10 years, if enclosed in an envelope and away from heat/light?

So that's the reason why services typically use 3 to 6 confirmations then, before my funds are accepted?

If my transaction's buried two blocks deep (2 confirmations) it's less likely to be in with a hacked or erroneous transaction and get orphaned? Then three blocks deep even less likely to be orphaned? Then four blocks deep even less less likely and so on...?

I think Bitcoin is complex enough to warrant a thread that we can use as a quick one line Q&A thread.

I'll start :

Q: I send a BTC and it has zero confirmations, so it's in the unconfirmed transactions pool. Once I get 1 confirmation does that mean it's now sitting atop of the blockchain, with all of the other transactions that make up that block? Or is the block not confirmed until I have x amount of confirmations?

Anything wrong with using electrum inside a Virtual machine with as password protected wallet for spends?

I'm aware that malware can get through the host OS and into the virtualized environment but surely it would have to be a lot more specialised to do this, especially if you only run your VM to access electrum and shut it down staight after. That way, you're only exposing your wallet  few minutes a week or less.

I think Breaking Bad ended in a good way and a sixth series would spoil it.

If Breaking Bad were being made today I'd say there'd definitely be a BTC plot in it somewhere.

What about a thermal Dymo machine for printing out and sticking private keys inside an envelope?

£20 from Amazon and once the batteries are removed I doubt any memory will remain.

Seems like a good idea to me. I only question how readable the print will be after a few years cold storage.

Any thoughts? I don't want to go through the hassle of punching characters into a sheet of metal, as has been suggested on these forums before.

Not that I think using metal is a bad idea: just too much effort for me.

I was thinking about this today:

How about using a Dymo for printing out a private key and sticking it to a card inside an envelope?

Not the old punch type ones. The newer thermal ones, like this:

http://www.amazon.co.uk/Dymo-LetraTag-LT-100H-Label-maker/dp/B0030453IM/ref=sr_1_14?s=officeproduct&ie=UTF8&qid=1408988286&sr=1-14&keywords=labelling+machine

Would this be any good?

Does anyone think that the print would fade after, say, 10 years inside a sealed envelope?

How about an old Commodore 64 if I plug a 56kbps modem in?

Anyone got bitcoin core on cassette tape?

How long before I can mine 1 BTC?

For me it's all down to personal circumstances: cost of living a comfortable life vs what I can afford to invest.

At the current price I'd like to own an extra 4 BTC by year's end. I may only buy 3 if I buy myself nice stuff in the meantime.

Excuse the question marks and BB code. The Bitcointalk app for android needs updating. :-)

Android is my personal choice for portable devices. For these reasons:

Interoperability. Myself, my family members and my partner: all Android phones so I can give them quick advice if they have questions/problems.

Custom ROM's: you can do [¡]anything[\i] on Android that you can on iOS and usually for free or cheaper.

Availability of devices. I would use a top end phone, such as a Nexus 5 or LG G2 if I could. But because my job is physical and my phone gets banged and knocked at work I'm using and old Samsung S2. It's full of scratches and dents but it still does everything I need. My girlfriend has the nice phone ?

Android is regularly updated and compatible with Linux, which isn't going away any time soon.


If you've more than a modicum of knowledge when it comes to tech then go Android. If you just want to look flash and spend more than you need, go iOS.

I don't own a tablet but if I did it wouldn't be an iPad. ?

On a tangent, and regardless of the terminology used to nominate Bitcoin, what happens if world governments finally hold their hands up and say "you know we said we were solving the financial crisis, well I'm afraid we can't and things are still sliding out of control."

Then bitcoin's gonna seem like a smart investment, whatever its going rate.

Why not install VirtualBox on the Windows PC. Then use a virtualized Ubuntu installation when you need to access your wallet?

Alles klar! Thanks!

What happens to transactions when I close down my node?

Say I have 12 connections (8 in, 4 out) and I have to reboot my PC due to a kernel update or whatever.

If I close down my node at the exact time someone is using it for a 255kb BTC transaction then will their Tx just be rerouted through another node? Is their Tx interrupted or lost?

Does bitcoin-QT or bitcoind temporarily halt system shutdown while it clears any current TX's?

Just curious, really. 

A vote for Electrum here. Don't store large amounts of BTC in it though. Just us it for everyday spending.

Use cold storage for your savings. There are plenty of guides.

I like electrum because I can write down 12 words that will recover my wallet no matter how badly I mess up my hardware. It's foolproof if you write down the 12 word seed and easy to use, too.

Not forgetting that home computing (i.e. hosting a 24/7 bicoin node) is becoming increasingly power efficient.

You can put together a nifty little home entertainment PC nowadays that uses under 30 Watts of energy at full tilt and about 10-15 Watts listening to music/watching movies/surfing. This is all capable of being done whilst running a node.