PBKDF2 & symmetric crypto(such as AES)

PBKDF2(Password-Based Key Derivation Function)

salt + password -> key

salt: randomly generated #
password: passphrase
PBKDFS hashes password multiple times with salt to derive a key value.


AES-CBC


data + (IV + key) -> encrypted data
encrypted data + (IV + key) -> data

http://en.wikipedia.org/wiki/PBKDF2

http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation)