Module newtypes

Newtypes used for sensitive data This module contains newtype wrappers for sensitive values. There are several reasons for this:

• We can make sure the information (such as passwords and pins) is not logged or sent to the backend by mistake.
• We control the creation and deletion of the objects such that we can ensure passwords and pins are non-empty, and also clear / [zeroize] the values once they are Dropped.
• We have control over the encrypt - decrypt lifetime of the password, making sure each value can only be used where it is explicitly intended to be used, and the encryption is only implemented and tested in one place.

In general the implementation follows this pattern:

• A struct that (privately) wraps the underlying value is defined.
• We derive [zeroize::Zeroize] and [zeroize::ZeroizeOnDrop] to make sure the value is overwritten with their zero value once Droped.
• We implement core::fmt::Debug that does not print the value itself but rather a placeholder value. This ensures the value cannot be printed or logged.
• We define (fallible) constructor functions that make sure the inner value is valid or return an Error. Additionally unsafe constructors can be used for circumventing the validations (eg. for use in tests).
• We define functions to get the inner value in safe ways (eg. as a [secrecy::Secret], or functions to convert (eg. for the encrypt / decrypt methods) to other newtypes.

Structs

AccessToken

Simple wrapper around a non-empty access token that cannot be printed or logged, and is automatically zeroized when dropped.

EncryptedPassword

An encrypted password.

EncryptionPin

A non-empty pin used to encrypt the password.

EncryptionSalt

A salt used in the encryption process. Should be unique for each encryption but is not a secret.

PlainPassword

A password that is not encrypted and stored as plain text.