4.3.0

• Add prehash_and_encrypt_password helper to hash passwords client-side and transmit it to an untrusted medium so it can be used to enroll an identity using the new PrehashedAndEncryptedPassphraseVerification method, available in python and ruby only.
• Add PrehashedAndEncryptedPassphraseVerification verification method, can only be used to enroll new identities.