Information on how to generate the key from a passphrase.
https://spec.matrix.org/v1.6/client-server-api/#deriving-keys-from-passphrases
The algorithm to be used to derive the key.
Optional
The number of bits to generate. Defaults to 256.
The number of PBKDF2 iterations to use.
The salt to be used for PBKDF2.
Information on how to generate the key from a passphrase.
See
https://spec.matrix.org/v1.6/client-server-api/#deriving-keys-from-passphrases