AES utilizing 256-bit keys.AES-256 is accepted by the US Government for protecting TOP SECRET data. AES is implemented in JavaScript for the LastPass.com website, and in C++ for speed in the Internet Explorer and Firefox plug-ins.

This is important because your sensitive data is always encrypted and decrypted locally on your computer before being synchronized. Your master password never leaves your computer and your key never leaves your computer. No one at LastPass (or anywhere else) can decrypt your data without you giving up your password (we will never ask you for it). Your key is created by taking a SHA-256 hash of your password. When you login, we make a hash of your username concatenated with your password, and that hash is what's sent to verify if you can download your encrypted data.