I'm reading the OP's question in a different way. He wants to ensure the private key has been written to disk so that if there is sudden power loss you don't loose bitcoins. Sort of an atomic operation. I don't think he's worried about some malware reading the keys from memory. If you have malware it could just as easily read the keys from disk.

(Also, electrum is coded in python not java. Your point about lack of low level hardware access stands, though.)

At one point there were 2 sha256 hashes in the OP one of which was correct. Then a few months ago the correct one disappeared.

Yes, that should do it. I would also write down a few addresses on a piece of paper. When you restore from seed on the new system just compare the addresses with the ones on the paper. If they are the same you know you have the same wallet.

Also make sure it does not say 'watch only' in the title bar of the electrum window in the new computer. You want to restore a seeded wallet not a watch only one.

BTW hard drive encryption on linux at least is not going to use pgp. I think symmetric alogs are used instead.

Outside of exchanges blockchain.info is probably the most popular of all wallets. As for exchanges their transactions are off-chain so we can't tell the exact numbers. But we know from what happened with Gox that most people keep their bitcoins in an exchange all the time.

You only have to count up to 3 zeroes. Take the default transaction fee for example. It's 0.0001. So anything with more than 3 zeroes is just too small to care about.

I hate mbtc. Still haven't figured out what people mean when they use that unit. I wish they would stick to btc. I'm used to the decimal point and the zeroes. It's actually quite easy. You just count the number of zeroes right after the dot to get some semblance of the value.

You only need to compute the stretched seed and master private key once. Then you can create address specific private keys at will.

Stop listening to roslinpl. Reinstalling or restoring from seed will not help. Do what dabura says and delete the config file. That is all you have to do. The location of the file is given below:

~/.electrum/config

An electrum seed consists of 32 hexadecimal digits. So just follow this guide to generate them:

http://world.std.com/~reinhold/dicewarefaq.html#hexadecimal

Then use the restore wallet function and paste in the hex. After the wallet has been created you can click on the seed icon on the bottom right to see the mnemonic.

Click on the red icon in the bottom right. In the window that pops up select another electrum server. Electrum servers are run by volunteers so sometimes they go down.

The multibit thing was overblown. One guy was affected by a bug related to importing blockchain.info wallets. That particular bit of code was done by a non-regular contributor to multibit who failed to keep it up to date. They've since removed that code entirely. I don't think you should discount multibit.

You can make paper backups of deterministic wallets like Armory and Electrum. In the case of electrum you make the backup as part of the wallet creation process. The backups are good for life for all addresses generated from the seed i.e. all addresses in your wallet except imported private keys.

Bitcoin mining is no longer profitable unless you are willing to invest at least a million rupees. Mining is now done with specialist devices called ASICs. They are not available in Pakistan and you have to import them yourself. You can see the prices for various ASICs here:

https://bitcointalk.org/index.php?board=137.0

Bitcoin uses SHA-256 so that's the type of ASIC you need.

People who do do mining in Pakistan mine alt-coins. Most alt-coins use the scrypt algorithm and now there are ASICs for that as well so GPUs are not competitive. For alt-coins that use other algorithms GPUs are competitive. But you have to invest a lot of time to a) find the specific alt coins that are profitable at this moment in time b) know when to dump them for bitcoins because they are highly speculative.

Disclaimer: I've never mined any sort of crypto currency. This is just what I've gathered from reading this forum. Please don't ask any follow up questions. Instead start reading on the mining sub-forum here.

You want to do all of this on-chain? It'll take a long time to do this on-chain. You will have to create a custom off-chain implementation so that only deposits and withdrawals are on-chain. Transfer of winnings from one user's account to another user's account should be off-chain or it'll be really, really slow.

Well see two people in this thread i.e. I and justusranvier have advised you against using paper wallets. Perhaps you should reconsider your actions.


I've already explained above. Paper wallets are dumb and primitive. Software (and perhaps future hardware) wallets are smart. With paper wallets you have to worry about change. With software wallets the computer does the work.


Yes you import the private key into blockchain.info. You spend money and think the private key is now empty. You make the private key public because it's empty, right? Later on blockchain.info sends change back to that key and someone steals your bitcoins. This sort of thing has happened to people.


Never *import* a paper wallet private key. Instead *sweep* the contents. That is an option available in blockchain.info and armory. Maybe mycellium as well. Other wallets don't have that option.

With sweeping the entire private key's coins are sent to another address in your wallet. It's an on-chain transaction. The private key is not imported into the wallet so change can't be inadvertently sent to it.

Anyway since people here are really, really interested in change I'll point out this article I wrote last year about how various wallets handle change:

https://bitcoinspakistan.com/blog/all-about-change-and-change-addresses/

Because those services exist to share files and are not secure. Hackers can take their sweet time trying to break into your gmail or drop box account to steal your wallet. Then they only need to bruteforce your password.

OTOH, if your wallet only exists on your PC, and perhaps a backup on a removable drive, then the hacker has to target your personally. Last I checked home PCs did not usually serve files to the general public so there are fewer avenues for attack.

Blockchain.info has an option where you can do that. Visit your addresses' page and click on request payment:

https://blockchain.info/address/1BitcoinEaterAddressDontSendf59kuE

Apart from this you can create a bitcoin: link:

pay me (NOT!)

Edit: Sorry I misread your question. You can't send the request to another person's BTC address I'm afraid. Closest thing is to make a public note on blockchain.info but it will only show up on that site and everyone can see it!

Change is something you only have to worry about if you are going to use a paper wallet. All other wallets implemented in software or hardware take care of change automatically and you don't need to worry about it.

I suggest you hold off on cold storage for now. Get  electrum and install it on your desktop and move the coins from coinbase there. When you've gotten the hang of using electrum on an online computer you can explore the offline wallet option. Avoid paper wallets at all costs.

Ha! Ha! That guy got angry because I did not give him enough sympathy. If you look at his post history you will see he disappeared after that. I help out a lot in the electrum forum and get thanked a lot. Perhaps you should take a closer look at my post history instead of judging me from some fly by night's tantrums.

14 million is not a lot relatively speaking. There must be at least a billion android devices out there.