* create srpVerifier from srpPW and srpSalt (as described below)
* deliver (email, stretchParams, mainSalt, srpParams, srpSalt) to the keyserver's "POST /account/create" API
To limit abuse, the createAccount() should also require a fresh "createToken". This should be created by some other API, outside the scope of this document, that perhaps requires a CAPTCHA or something. createAccount() might also require a proof-of-work token, as described below.
The server, when creating a new account, creates both kA and wrap(kB) as randomly-generated 256-bit (32-byte) strings. It stores these, along with all the remaining values, indexed by email, in the account table where they can be retrieved by getToken later.