Chore: Update the people.email to use Fields.EmailEncrypted

[nelsonic]

As noted in #284 sadly, by default the mix phx.gen.auth generator
does not setup any protection for personal data in the database. 😢
Email addresses are stored as plaintext:

Similarly the people_tokens table stores email addresses as plaintext in the sent_to column:

This is obviously undesirable. 🙃
This is a privacy/security issue waiting to become a scandal!

Todo

• Re-add fields to the newly re-created auth (Phoenix 1.7) app
• Update the people and people_tokens schemas to use Fields.EmailEncrypted
• Update tests as required

This shouldn't take very long but allocating T2h to allow for documenting the steps

[nelsonic]

Getting the following error:

15:06:13.691 [info] alter table people
** (Postgrex.Error) ERROR 42804 (datatype_mismatch) column "email" cannot be cast automatically to type bytea

    hint: You might need to specify "USING email::bytea".

[nelsonic]

Sadly, having the person.email and person_tokens.sent_to in plaintext is relied upon by the following query:

auth/lib/auth/accounts/person_token.ex

Lines 110 to 129 in da0af7e

	def verify_email_token_query(token, context) do
	case Base.url_decode64(token, padding: false) do
	{:ok, decoded_token} ->
	hashed_token = :crypto.hash(@hash_algorithm, decoded_token)
	days = days_for_context(context)
	query =
	from token in token_and_context_query(hashed_token, context),
	join: person in assoc(token, :person),
	where: token.inserted_at > ago(^days, "day") and token.sent_to == person.email,
	select: person
	{:ok, query}
	# phx.gen.auth boilerplate code not yet covered by tests ...
	# coveralls-ignore-start
	:error ->
	:error
	# coveralls-ignore-stop
	end
	end

I don't see us using this function in our auth implementation
because this is the flow/journey where people click on a link in an email to verify their email address
and we are definitely not doing email verification with links.

see: #223 (comment)

So I'm going to explore removing this function and seeing what the ramifications are ... 💭

[nelsonic]

Following the changes made in: 2bbba99

If we now run a query to view the data in the people table:

SELECT id, email, inserted_at FROM people;

We see that the email is now a binary blob

Registration and Login still works as expected:

But now the personal data captured in registration is stored encrypted at rest the way it should be. 🔐

[nelsonic]

captured in: https://dwyl.github.io/book/auth/09-encrypt-data.html