Electrum

Electrum is a lightweight Bitcoin client, based on a client-server protocol. It was released on november 5, 2011.

Main features:

• Encrypted wallet
• Deterministic key generation. If you lose your wallet, you can recover it from its passphrase.
• No blockchain download; the client requests that information from a server
• Private keys are not shared with the server.
• Firewall friendly: The client does not need to open a port, it simply polls the server for updates.
• No single point of failure: The server code is open source, anyone can run a server.
• Python. Very compact code, easy to contribute.

Brain Wallet

Electrum uses a type 2 deterministic key generation algorithm. This means that all the keys are derived from a seed.

Electrum makes it easy to memorize its seed, because it uses a mnemonic code.

Example:

• hexadecimal: 8a44dfd6ad4f687b5e3c80563c327027
• mnemonic: "shade weave eternity kept true tangle new talk clay warmth fish match"

Multiple wallets

Electrum uses one single file per wallet. Your default wallet is located in your user account. If you want to use another wallet, use the -w option followed by the wallet path and name:

$ ./electrum -w /path/to/my/wallet/wallet_name

Export and import addresses

You can export your private keys using the 'addresses' command:

$ ./electrum addresses -ak
Password:
1LGoehbyeX4QBEPK1a6dhyaoMQZfqg5LKX:5JBSttEGhjEcPidSovW66Rin2EZ6LEHZ2qx8Pu2RqqNaDTBVWaF   
1KcsBJa2cCxVkGJfSsg5bUeXN7Y5uLa8mP:5KiP4uiNT6KG8jnXbainCM8rDWRrgxt3PAyut4FFpDoCo1Rh6VM   
1PXsn7LVXTccGhJPTUL8r2EGB4fF9kvex3:5Kj8mvBJReyk8xEBMx5cTnciQCxto5JmudiTPkqwMcd61Kf1Jqc   
1KteSFTAphyByLTtUfFiVQ9s7fMVmx7c2h:5JeZ3FTbWcksLt3PKydd5U9p952UQRHwv3LoxzCA9LZ7V2bku5p   
1GE5ZChAobeTEPLHDCDDKTSg3XvLkcQFjS:5JwtGEygTwF2nouhRVzW3w5DWZd1sCgxLtnd1v51wjkbUrp5sqH   
12YNehfAoYTiwjTXULwaZqTCauu2D61fq6:5Jvcq19ePCXKcVun4n7US99CsrEByUK2kgxXBA3rBVBqYZjhfwD  [change] 

The option -a means: 'list all addresses' The option -k means: display the private keys

You can also import addresses into an electrum wallet, with the 'import' command:

$ ./electrum import 1LGoehbyeX4QBEPK1a6dhyaoMQZfqg5LKX:5JBSttEGhjEcPidSovW66Rin2EZ6LEHZ2qx8Pu2RqqNaDTBVWaF
keypair imported

Note that imported keys do not belong to the deterministic sequence of your wallet; if you import keys in a wallet, you must backup it up!

Screenshot

Security

See Thin Client Security

links

• homepage: http://ecdsa.org/electrum
• source code: https://gitorious.org/electrum
• download: git clone git://gitorious.org/electrum/electrum.git