Yesterday's story too involved a blockchain.info wallet and funds sent to the wrong address. (the bitcoinstore and Roger Ver drama)

Could these two problems have a common cause? I mean, a software problem at blockchain.info.

"WARNING - a webwallet is AS SAFE AS ITS ADMINS"

That is correct, but Electrum is not a commercial operation.
It is a free software project, that involves multiple developers, not just me.

what is the percentage of your users that install it?

reserved too!

I just wanted to mention that a skilled blockchain.info admin can perfectly steal your funds. He just needs to change the javascript sent to your browser in order to get your password.

Roger, can you please cool down, blank your first post, and seek a better outcome than a flamewar?

I don't want the next news article about Bitcoin to be entitled "In the lawless Bitcoin world, business owners seek revenge by publishing customer information"

it's not just going to hurt his business, it will also hurt blockchain.info, and Bitcoin. please remove the thread ASAP

You posted his name and address. if I was you I would remove that information asap.

You are destroying the reputation of your business for 4.5 BTC.
do not let anger guide your reactions, try to be rational.

I agree. Posting the private information of one of your customers will bring negative attention to your business, and it will not get your money back. Not very professional, IMO.

If want to do something about a scammer, report him to the police. Do not try to be your own police, or your business will be affected.

yes, that's how the -w parameter is supposed to work. please read the manual next time.

This is not corruption. This is because you upgraded to a version with SPV.
With SPV, the dates of transactions will be displayed only once transactions are verified. this might take a few minutes (time to download the blockchain headers).

there is a new file called blockchain_headers. this file does not store any information that is specific to your wallet.
I added a -P option in the 1.5.7 version, that makes it portable. with this option, the client will always write that file in the same directory as the wallet.


Because portable wallets can (and will, it is only a matter of time) be used by some people on third party computers.
The administrator of the computer where you use your "portable wallet" might install a keylogger, get your password and decrypt your wallet.
And please don't tell me that you are not stupid enough to do that. Some people will. I don't care if it's you or someone else.

Also, please understand that "portable wallets" were never officially supported in Electrum.
Flatfly's version is not the official version, so it is not as if I was removing support that existed in the past.

Please note that "portable wallets" expose users to a big risk of theft. This is why I never really wanted to support this function.
However, there seems to be a strong demand for it, and we cannot prevent users from doing what they want, so I guess it is better to include proper support for it.
I have been talking with slush about it, and we plan to support it soon.

your wallet is not lost, even if your client cannot connect.
there are at least 3 ways you can recover your bitcoins:

1. use the -w parameter:  if that does not work with flatfly's version, it will work with slush's build.

2. recover your wallet from seed:  
start your old client, go to the seed dialog, and write down your seed.
then, start the new version of Electrum, and instead of creating a new wallet, select 'restore from seed'.

3. if you don't want to use Electrum at all, you can export your keys to another client:
you can do it offline, with the command:

can you please count how many users reportedly lost money because of Electrum?
sorry, but this too had to be said.

the same author also wrote this article, where Bitcoin is cited:
http://www.ericsson.com/m-commerce/2012/11/12/virtual-currencies-and-the-functionality-of-money/

You are completely missing the point.

The security model of open source software does not mean that each end user has to inspect the code they use. Most users do not have the skills to do that.

Electrum is an open source project with an active community of developers.
This means that there is an open community of people who read the code, and inspect changes made to it.
If one of the developers decided to introduce malicious code, others would detect it.
This is how open source projects work.

In contrast, Javascript code dynamically attached to a webpage does not give you that security.
A malicious server operator can modify javascript code instantly, before it goes through a reviewing process.
It can even send different code to different clients, in order to remain undetected.



Yes, you can download javascript from github, and execute it locally.
But how many people actually do that? unskilled users won't, because it is too complicated for them.

My point was that users should stay away from websites that dynamically send you javascript.
This is a very different (and much more dangerous) situation than downloading code from github.

Unfortunately, people who do not understand this distinction might interpret your answer as a refutation of what I said. Please clarify.

1. stay away from brainwallet.org, bitaddress.org, or from any website that asks you to enter private keys, or that creates your private keys using javascript.
It is very easy for the operator of such a website (or for a hacker getting access to the site) to covertly change the javascript sent with the page, and "disconnecting the internet" will not protect you from everything (malicious code can also save your private key in a cookie, or elsewhere, and send it later).

2. There are two types of "brain wallets": a single Bitcoin address, or a deterministic wallet, that creates as many addresses as you need, and better protects your anonymity.
If you use a deterministic wallet, you must know this: never ever use "redeem private key" services offered by websites (such as mtgox); it might expose all the other keys of your deterministic wallet, not just the key you redeem.

3. Try Electrum : http://electrum.ecdsa.org . It is one of the easiest to use Bitcoin wallets, and it will protect you against your own mistakes.
Of course it is a bit more difficult to download and install software than to use a website that runs with javascript. However, when you use a website, you are putting your funds at risk.

4. Do not donate to me. This advice is free.

The Bitcoin world has had enough large scale scams. I decided to write Electrum after the mybitcoin.com fiasco, because I realized that a large and economically relevant fraction of Bitcoin users will always be attracted by wallet services where they do not need to download the entire blockchain. While I reckon that the security of Electrum is not as high as the official client (because it does not download the blockchain), it is much safer than any javascript wallet you'll find on the web, for the same level of convenience.

I did not say it would be bad.

I use 128 bits because 128 bits is secure enough.
Now, if you want to have more entropy, the correct way to do it would be to first pick a random number of n bits, then derive the key from it.
A private key is not completely random, therefore its entropy is less than its length.

Note that even though Bitcoin private keys are 256 bits long, their hash used to create Bitcoin addresses is only 160 bits. So the actual level of security offered by Bitcoin addresses is 160 bits.

The seed is a 128 bits random number, generated by os.urandom()

The seed is represented as a sequence of words in order to facilitate memorization and storage, but it can as well be represented as a hexadecimal string, or as a number.
For some reason, people tend to perceive words as "less random" than numbers. That's an illusion.

The only thing that actually matters is the number of bits of entropy in your seed (128 bits is considered as very safe, and will probably remain safe until real quantum computers are invented), and the quality of your source of randomness (electrum does not use python's random module)



No, that does not make sense. A private key is not a random number.

you can also specify the default wallet path in /etc/electrum.conf

it looks like he is using python3