Cold storage has been discussed in the past on Ethereum's subreddit.
Just to give my 2 cents, on Ubuntu I use the following on the command line:
cat ~/.ethereum/keystore/<key_file> | qrencode -o qr_image.png
Add option -l H to get a code that is easier to decode. The qrencode tool uses the open source libqrencode library, and can be installed using:
There is a paper wallet generator available at myetherwallet.com.
If you don't trust it, you can download it from github and run it offline.
There is another paper wallet generator available at ethaddress.org.
Source code on github.
Great answer by Nikhil already. I'll add that you can download the repo from github and save/run it locally on your computer in the future. The MyEtherWallet team has no intentions of ever taking it down as it costs us almost nothing to maintain and keep online.
Here are the 3 URLs you can find it at
https://www.myetherwallet.com (served via Github w/ custom ...
myEtherWallet.com does not save your address and keys, it says
MyEtherWallet.com does not receive or store any information so we
cannot recover your wallet if you lose you password or private key.
Once you create an address they will provide a .json file or a .pdf file with the public and private keys of your wallet.
Technically there is no problem ...
Our full guide can be seen and read here: https://myetherwallet.github.io/knowledge-base/migration/moving-from-private-key-to-ledger-hardware-wallet.html
Basically, use your private key to unlock your wallet on MyEtherWallet and send the funds to the address controlled by your new Ledger device.
There are several bitcoin standards related to creating keys from mnemonic seeds.
BIP 39 for making mnemonics to create a seed:
BIP 32 for deriving keys from that seed:
However, not all clients use all these standards (eg Electrum'...
When you mouseover the blurred private key code, the QR code sharpens (helps with security preventing shoulder-surfing, it seems). And if you print the page, the CSS of the page modifies itself to un-blur it when printed.
Same thing with the text representation of the private key; it's normally shown as a line of asterisks, but if you hover your mouse over ...
Take a look at :
( and mainly, this file, search for generateSingleWallet : https://github.com/kvhnuke/etherwallet/blob/gh-pages/js/source/01_global.js )
It is the source code for the https://www.myetherwallet.com/ that provides in-browser generation of ethereum addresses.
There are a few different reasons for verifying your key.
To make sure you actually saved the private key and address correctly. e.g. You saved a private key but recorded the address 0x122... instead of 0x123... (note: you should avoid hand writing things anyways).
To make sure you have all the necessary information, including the password. e.g. You ...
No. clients need to be updated. MyEtherWallet.com has updated the geth instance they use and so you do not need to do anything.
If you downloaded the repo, you can download a new version which has been updated to support checksums. Otherwise, no need to do anything.
Yes, you can simply generate pairs of unencrypted or encrypted private and public keys. For example, use this bulk key generator:
Printing the private key for ethereum in geth.
This is done for creating a real *secure offline paperwallet in your own WM which afterwards stores the money independent from a program *.
Based on this posts and another post that points out that the source code of geth can easily be changed to print out the private key. Here it how it goes.
Create a ...
If an Ethereum wallet address was created using MetaMask
It doesn't appear so, at least during creation. (You can verify this by watching for network traffic during the creation process.)
can the IP address of the wallet's owner be logged or uncovered somehow?
By default Metamask uses Infura. When submitting transactions, traffic routed via Infura will ...
A paper wallet is a way of storing private keys which give you control over an Ethereum account (which includes the ether associated with it and any tokens it has). Each account essentially includes a number associated with it (the ether balance) and every ERC20 smart token contract contains a mapping of addresses to token balance. The account balance can't ...
You can have unencrypted private keys, of course.
Mnemonics is what can be used to derive this private key. So this can be used to generate a mnemonic (select ETH), and further down the site you can find the corresponding unencrypted private keys and addresses. They are all generated from the same mnemonic using a different derivation path, but when ...
Did you create the address while online? It is almost impossible to brute force a private key in a life time with current computer power, much less several of them in a very short amount of time. The recipient address has a total 10 transactions in less than 15 minutes, you were not the only victim.
One possibility is you inadvertently used a scam site, or ...
This code is mostly correct, but there are two small issues:
Before hashing the public key, you need to drop the first byte. The first byte often indicates whether the key is compressed or not. In Ethereum, the value must always be uncompressed, and you don't include the prefix when hashing.
buffer2Hex appears to be broken.
Here's a fixed version of ...
The aim of a hardware wallet is to never expose the private keys for the addresses it generates. The wallet doesn't want anybody to ever see those private keys. Instead of trying to determine if you're you, or if you're a hacker, this system just assumes that you're a hacker.
Why assume that can be trusted? If you're you, you shouldn't need to know the ...
If you just want to view or transfer your funds around, you're right that a private key is enough. You can use MyEtherWallet (beware of scam sites) to do so.
And unlock with your private key.
You cannot do this. The Ledger is a hardware wallet that's meant by design not to allow exposing your private key to anyone (not even yourself).
If this was possible, the minute your private key is exposed your hardware device stops being secure.
MyEtherWallet and MyCrypto don't have access to your private key. Whenever you need to execute a transaction, ...
Based on Richard's answer I created a bash script to build a more readable paper backup. As shown in the following example , the paper contains the address (to not confuse multiple keyfiles/papers) and the keyfile in both plain JSON and QR-code.
Such paper wallet is just a backup with same security as backed up keyfiles on a normal USB stick. In contrast ...