Current password-based KDF in nucypher/py-umbral is excessively slow. This can be due to several factors:

• Election of parameters: Current parameters are typical for file encryption. While this might be OK for Ursulas (which have a high keystore diligence requirement), it's not for Alice. A possibility is to keep similar parameters for Ursula, but reduce them for Alice or other characters.
• Implementation: Some have noted that our current implementation (from cryptography.hazmat.primitives.kdf.scrypt) may be too slow in comparison with others. Investigate other alternative implementations.
• Election of KDF algorithm: @tuxxy has mentioned their interest on Argon2. Investigate what's the performance.