Electrum's focus is speed, with low resource usage and simplifying Bitcoin. Startup times are instant because it operates in conjunction with high-performance servers that handle the most complicated parts of the Bitcoin system.
What is the Seed?
The Electrum Bitcoin client uses a 128-bits random seed to generate its private keys. The seed can be represented as a 12-words mnemonic code. You do not need to perform regular backups, because your wallet can be recovered from the seed that you can memorize or write on paper.
What encryption is used for wallets?
Electrum uses AES-256-CBC to encrypt the seed and private keys in the wallet.
Can I do bulk payments with Electrum?
You can use the CSV import feature to make bulk payments. It can accept either a CSV file or CSV entered into a text box. The rough format is:
"ADDRESS","AMOUNT"
"ADDRESS","AMOUNT"
Does Electrum support sending to multi-signature addresses?
Yes Electrum does support sending to multisig addresses or P2SH addresses (addresses starting with '3').
Can Electrum create and sign raw transactions?
Electrum lets you create and sign raw transactions right from the user interface using a form.
Does Electrum support cold wallets?
Yes. It also supports an easy and safe way to spend your coins in cold storage from an online computer.