Bitcoin Forum

Say i put ubuntu on usb and boot from it and now generate 1 paper wallet using bitaddress.org gitup file locally and then instead of printing this i ssved it as pdf and then after booting back to windows i put this pdf in .rar file with secure password protection and save this file in mutliple places.Then even if i use the internet i won't be at risk right?
is bitaddress.org paper wallet generation really random?
and last question if i have say 7 bitcoins on this digitally stored paper wallet and i want to spend 2 bitcoins from it and want to have 5 bitcoins in it.Can i do so? because i have read somewhere that we need to sweep the paper wallet and why's that?Can't i just spend directly the amount i wish to spend?

P.S i don't want to print a paper wallet because i am too paranoid i may lose the paper or damage it

This can work, if your password is strong and you do not forget it.

It should be.

Where does the 5 bitcoins change go? The risk is you lose it if you do not swipe the whole paper wallet in one go. You can make 7 paper wallets, each holding 1 bitcoin.

Print it 5 times :)

Why not encrypt it on your throw away USB stick OS? If you move the PDF unencrypted to a different machine it make no sense to set up the USB stick OS in the first place as it offers you no additional security.


Yes, even on low entropy systems (e.g. new OS on SSD/USB stick). The mouse movements required at the start provide enough entropy to make the key generation random.


Yes, if you are careful. More below.


The "problem" with spending paper wallet funds are the software you use to do so. If you have 7 bitcoins received to a paperwallet, these 7 bitcoins are considered one or more inputs you can spend. Lets assume for simplicity you have only one input. You can think of it like a 7BTC bill or a lump of gold (I will go with the gold for this example). If you want to spend the 7 BTC lump you have to melt it down and create pieces of lesser value. Different wallets do this differently. Some would send the 5 BTC you want to keep (assuming no fee for simplicity) back to the address you previously had the 7 BTC on. Some would create an entirely new address for this. Its best that you prepare another paperwallet and manually send the lump you want to keep to it.

E.g. you have 7 BTC and want to send 2 BTC to Alice while keeping the remaining 5 BTC. You use the funds from your old paper wallet to create a TX that sends 2 BTC to 1ALICEvanity and 4.9998 BTC to 1myNEWpaperWALLET the remaining 0.0002 is used as fee.

Secure your paper wallet with BIP38 password first before placing it into Windows.
AFAIK, yes.
In Bitcoin, the condition, Input=output must be fulfilled. If you have an output or multiple outputs that total up to be 2 Bitcoins, you can spend them and leave the remaining UXTOs untouched. You can also send the change back into the paper wallet. However, this is not recommended since the paper wallet is unsafe after touching the internet. Sending the change to another newly created paper wallet is much safer.

I already do this on my windows computer. I simply have several paper wallets stored in a zip file and with very strong encryption. Passphrase is a combination of 50 characters, which I find to be strong enough. And all this sits in my USB drives offline together with my wallet.dat backups.

You could save the pdf file on a cheap USB stick or onto a microSD for safe keeping. Why would you want to save it to your Windows system and bother to encrypt/decrypt it all the time. Yes I think bitaddress.org wallet generation is completely random. Also there are special features within Bitcoin wallets that allow you to spend from Cold Storage. If you explicitly run that option the change will be returned to the original address so your remaining coins won't be lost after completing the transaction.

If you put it in a drawer, paper may survive longer than USB, statistically.
And checking or xeroxing paper has less security issues than reading or duplicating an USB stick. This is an operation you may have to do from time to tims.

Ok i have read that mycellium bitcoin wallet alows spending from cold storage so if use it to spend 2  bitcoins from paper wallet will the remaining 5 btc goes back to my paper wallet?and why the new 5 btc that comes back to the same address do not show as new transaction?
And yes how do i encrypt the pdf on throw away ubuntu system that i used to create the wallet?
And what if i use Electrum instead of bitaddress.org to generate the address as i think electum will be much safer.right?

Unless it has changed from what I remember is that Mycelium has a "sweep paper wallet" feature.
Using this feature is an easy and safe way to move the btc from your paper wallet.
Just sweep the lot, make the transaction you want using the Mycelium wallet and then send the change back to a new paper wallet you have created.

Just split up your coins my friend. Let's say you will possibly use some { 3 for instance } in the near future.. then keep them online on different wallets and keep the rest in cold storage on paper wallets. You

can even keep these {let's call them "spending money" } on a hardware wallet like a Trezor and keep the other { Long term storage} on paper wallets. Separate those coins {the remaining 4} on 4

different paper wallets and sweep them as you need them. Does that make any sense to you? { My split is 30% useable coins online & 70% cold storage }

Splitting the btc into different wallets and addresses is a good idea but 30% online would be too much for me.
Its so easy to access cold storage now that I would never keep more that 5-10% online, why even give hackers a chance, you will regret it later.

There should also be a backup paper copy of all these, laminated then stored in a safe container/fire-proof box. Just a suggestion because as for me I don't entirely trust a couple of USBs, they break down eventually.

If it's in an offline storage, such as a pendrive or such, I don't see any problem.

I have two physical copies of each paper wallet stored in different places
And as insurance, I have it on a pen drive stored in a third location

It's not a bad idea to print out a paper wallet in addition to saving the pdf file of your private keys in a safe location just in case. You can laminate the paper to make it withstand water and moisture and you never know you may one day need it to recover your funds if you lose your other copies because any electronic equipment may fail and paper if taken proper care of can last a very long time.

papper wallet is already safe storage,and of course if we store it on zip file and with very strong encryption,it might the safest way to store your bitcoin,i just wondering why are people like you so afraid with bitcoin security?do you ever lost your bitcoin?os you store so many amount of bitcoin,then you think you must do this all security.

i have printed once but i moved the coins (spent) and now i am doing something similar only because i don't have a printer and i don't want to use a public one.

the problem here is that all the electronic devices can fail, there are a lot of reasons for that like device malfunction or bad sectors than can make the file inaccessible.

so i am keeping it in multiple places until i find a better solution!

Do you use password protection on the paper wallet? I want paper wallets for long term, and I want my kids to be able to access them in 50 years if necessary. A password means I am the only one who can use it, while no password means an intruder can use it.

It is how most clients/chain explorers display the transaction. Since the ~5BTC is obviously the change, there is no need for the client/explorer to display it as a new transaction that was sent to the address.
I am not particularly sure. I believe PDFtk[1] can help.
I'm not sure about how safe it is. However, it is a better choice to use Electrum as a offline wallet generally.[2]

[1] https://www.pdflabs.com/docs/pdftk-man-page/
[2] http://docs.electrum.org/en/latest/coldstorage.html

I do this very thing, i have paper wallets which i also have stored on a usb pen drive which i keep in a safe.  This drive never gets used on a computer which can access the internet.  ;)

AFAIK not, the way I understand what mycelium does in this case is that it sends the 5 BTC to a newly generated change address that is part of your mycelium wallet. I also think its a bad idea to reuse a paper wallet. The whole idea is that you have an offline key, one that was never on an online system and thus can not be affected by a virus. This is longer the case once you use the paper wallet at least once. Hence the suggestion to create a new one. On the other hand you dont store it on paper either, so maybe something like Tails[1] is better?


Because its the same transaction. A transaction can send coins to many addresses at once.


PGP should be available by default or you could use something like e.g. VeraCrypt (which is based on the famous TrueCrypt) sinec you need to get some software on the stick from the internet anyway.


I dont think it matters much. You might want to use electrum from a live OS like Tails though since this would solve your "change" problem. Instead of a private key you would secure the seed and restore the wallet from that every time you want to spend some coins. The seed would (unlike a private key) cover all future change addresses and can offer you different addresses as well. Electrum is also preinstalled on tails, so you would not need to install any software. Tails does not come with VeraCrypt yet[2], but they have different means to help you encrypt data.

[1] https://tails.boum.org/
[2] https://labs.riseup.net/code/issues/8911

Thanks
I know Tails Come With Electrum
But can you tell me how can i install electrum on any linux distro not just tails?
Because i have read electrum is not easy to install on linux so can you please suggest me how to install it?

Of course it's not good, because the main idea of 'Paper' Wallet is to keep your wallet on a 'paper'. If you're not save it on a paper, well then you can't call it a Paper Wallet.

Sometimes it is better to store the paper wallet or scanned docs digitally but only if you have encrypted those and your save the password or the key to decrypt it later when you need it, but if you can store physically somewhere.

A more general name is "cold storage", which can be in any physical form. The main importance is to keep the private key offline until you use it.

Terminology isn't so black and white on this topic imho, because you have "paper" wallets printed on steel and other materials due to their higher endurance, resistance
to fire and other advantages. But still, i wouldn't save it digitally as per op, because it kinda loses it's point.

Good idea, but you must be carefull dont lose your password


why not to generated 7 papers wallet, and make them to the one pdf, i think it could be easy to used, you wouldn't be cost by the fee if you spent the amount separately

You can save it on a place where you safe your secret and important document, just saying

With a really strong password, that you can remember and that was made offline without any key-loggers should suffice but instead of putting the pdf in rar why not use BIP38 and encrypt the key with the pass phrase whilst making it?

Well electrum runs on python and I dont know of any distros that dont come with python. I just download the tar.gz[1] from the sources section, extract it[2], change into the newly created folder and run it with python electrum. If you do everything from terminal, the following steps should start electrum for you on any linux distro. You will need to copy the public key[3] from ThomasV into a file named thomasv.asc first though.


If you already have electrum on your system it will open the last wallet. If not it will promt you to create a new one.

[1] https://electrum.org/#download
[2] tar -xvzf filename
[3] https://pgp.mit.edu/pks/lookup?op=get&search=0x2BD5824B7F9470E6

I am happy to say that I never lost any coins, and that's because I take security very serious. The coins that I have right now may end up being worth a lot in the future. So there are plenty of reasons of why I should keep the security level as tight as I have right now.

Saving the paper wallet digitally kinda negates the purpose of paper wallet itself lol :P
But yea, by saving that on winrar with a strong password should make your private keys unobtainable
and yep, you need to sweep the paper for that, because there's no change address to where the 5 bitcoin should be at

the whole point of paper wallet is to keep it in paper form and if you are keeping it digitally then it is not paper wallet but just a cold storage if it is never connected to internet.

the benefit of paper wallet is that it can not go online by mistake so unless someone breaks it your house they are safe from hacking

Instead of sweeping the wallet you can use Brainwallet in offline mode to generate transaction,  copy it ( it has nothing to do with private key,  you are secure while copying),  broadcast it using blockchain or any other broadcasting service.

Above quote indicates a general form of increasing security to the wallet. I believe having few wallets to hold our bitcoins and having two factor authorization is enough. Even if needed can go for the saving of paper wallet in digital form.

Brainwallets have been hacked a lot and are very risky. Read http://www.wired.com/2015/07/brainflayer-password-cracker-steals-bitcoins-brain/:

It's just funny :)

Bitaddress isn't truly random. It is based on the seed (your mouse movement), which isn't random. Human movement always follows some pattern or purpose. Mouse movement is no different. In fact, in some ways, nothing is random. "Randomness" is the misconception of not being able to define the answer because we do not have the means to.

People say "probably fair" gambling is totally random, but if we know the server hash, we can predict what is going to happen. It's not so random after all.

So according to you 1 address  can be generated  (or have been) twice by bitaddress.org offline version?

Open MS Paint, and draw a line with your mouse. Now try to draw the exact same line again.
'True random' may not exist, but that does not mean you can reproduce it.

You can store it securely using PGP encryption just save it in a text file and make sure you keep the keychain on a usb stick or somewhere separate, not online and you will be safe it's all good buddy.

Its a PRNG[1] and as such considered random enough for cryptographic purposes.


Randomness is defined as the lack of pattern, we as humans are essentially pattern matching and recognition machines. Just think about all the people that see the face of Elvis in vegetables. If we are unable to see a pattern we call it random. This lack of pattern is what protects a randomly generated key. IF there would be a pattern between the first and the next key you generated it would be possible to derive one from the other. Since you cant its perfectly fine to call it random, unless you want to start a philosophical debate.

[1] https://en.wikipedia.org/wiki/Pseudorandom_number_generator