Electrum (https://electrum.org/) is an open-source, light-weight Bitcoin client, available on Windows, Linux, OSX and Android. This post aims to give the reader a quick introduction to its usage and features.
Full-node Bitcoin clients, like the official Bitcoin Core client, maintain a copy of the whole blockchain on the machine the client is installed on. By contrast, light-weight clients such as Electrum rely on a server to provide the transaction history for a wallet and to broadcast new transactions to the bitcoin network. This means that the client can skip downloading and synchronizing the whole blockchain (over 28GB at the time of writing), resulting in virtually no startup time and much, much lower space requirements.
Choosing “create a new wallet” automatically generates a wallet from random data, and gives you a seed that can be used to restore the wallet in case of computer error. Write down the seed and store it in a safe place!
Electrum supports encrypting the private keys associated with a wallet using the AES-256-CBC algorithm. Create a password for the wallet if you wish to do so!
As of 2015, LocalBitcoins hosts an Electrum server, electrum.localbitcoins.com, which is available using the SSL (port 50002) or TCP (port 50001) protocols.
After connecting to the server, you should get a window with your transaction history (empty in case of a new wallet) and a green light in the bottom-right corner. In case the light is red or the top-left corner reads “not connected”, click the light button and select another server.