This should be a trivial problem for anyone who is properly managing his or her Bitcoins. A group called the “Large Bitcoin Collider” claims it can smash open bitcoin wallets by using a so-called brute force attack, which directs mass amounts of computer power at individual wallets in order to guess their private keys.
A “trophy list” on the home page of Collider (an apparent reference to the Hadron Collider) suggests the group has successfully opened over a dozen wallets, though only three had any Bitcoins in them.
You can read more in an article in the Fortune web site at http://fortune.com/2017/04/15/bitcoin-collider/ although that article appears to be written by someone who doesn’t know much about Bitcoins.
The ‘Large Collider’ Attack appears to only work on Bitcoin wallets that store their information online or in a cell phone or tablet computer. Indeed, there are dozens of such wallets for Android, Apple iOS, Windows, Macintosh, and Linux systems. Online wallets are very convenient to use and are apparently quite popular. However, only a Bitcoin novice will ever store a significant number of Bitcoins in an online or cellphone wallet.
A hardware wallet, perhaps best referred to as an offline wallet, is far more secure. Most hardware wallets are based on a small piece of hardware that can store the Bitcoins or other cryptocurrencies. Many hardware wallets resemble a USB flash drive. The hardware wallet typically is attached to a regular computer, most often Windows or Macintosh or Chromebook or Linux, and the Bitcoins are transferred to that piece of hardware for storage. The hardware wallet is then disconnected from the computer and powered off.
Even the ‘Large Collider’ Attack cannot steal Bitcoins from a device that is disconnected and powered off!
Similar hardware wallets are also available for most other cryptocurrencies, such as Ethereum, Litecoin, Dash, Monero, ZCash, Ripple, and others. Many of the manufacturers produce hardware wallets for multiple kinds of cryptocurrency.
If you use any cryptocurrencies and if you have more than about five dollars in your wallet, you need a hardware wallet! Otherwise, your cryptocurrency is at risk.
For more information, perform an online search for your cryptocurrency followed by the words hardware wallet. For instance:
Ethereum hardware wallet
If you are not yet familiar with Bitcoins and other forms of cryptocurrencies, you might want to start by reading the introduction at; https://bitsonblocks.net/2015/09/01/a-gentle-introduction-to-bitcoin/ or watch the series of videos starting at http://bit.ly/2oeIMQn.