Re: [Passwordsafe-devel] Thoughts on TOTP/HOTP support in PasswordSafe?

[Bill B. <de...@bl...>]

On Fri, Oct 04, 2019 at 08:13:07AM +0300, pwsafe.org wrote:
> A few thoughts:
> 
> - This will require format changes - at least one new field to indicate the
> entry is for a OTP, and not a "regular" password.

I was just looking through the format docs for V3 and V4, and they both
list "Two-Factor Key" as a (yet to be implemented) field type (0x1b).
Is it safe to assume we could use this?  Though we would still need
additional fields for OTP parameters (e.g., hash algorithm, length of the
generated code, etc.)

Since applications are supposed to be able to handle unknown fields in a
forward-compatible way, it seems like there shouldn't be an issue with
adding new fields to the existing formats (as opposed to waiting and
adding it to the next format).  Is this correct?


> - Are the specs for the various authenticators out there (Authy, Google
> Authenticator, etc.) publicly available and usable to implement a clone in
> pwsafe?

Yes, the HOTP spec is RFC4226 [1] and the TOTP spec is RFC6238 [2].
While I wouldn't be surprised if certain vendors had "peculiarities"
with their implementation, I'd expect the vast majority of differences
to be handled by changing the OTP parameters.

> - The biggest challenge for implementing this is to do so in a way that
> won't "penalize" the users of "classic" passwords. By "penalize" I mean
> require extra clicks/keystrokes over what's required today to create and
> use a given entry.

I'm open to other ideas, but my initial thought for the UI is

  - The entry's view/edit dialog would get an additional tab for
    OTP-related configuration.  On this tab, the user could enter their
    seed/key and configure their parameters.

    Since I expect that the average user doesn't want to have to know/care
    about which hash algorithm to choose and similar things, I think we
    could create some "presets" for common configurations, and give them
    user-friendly names/descriptions.  Then also have a way for advanced
    users to manually set the parameters if needed.

  - The entry's right-click menu would get two additional items:

      - Display Authenticator Code - opens a dialog that shows the code and
        time remaining indicator (similar to how "Display Password as QR
        Code" opens a dialog today).  This basically presents the same
        interface as most authenticator apps.  There could optionally be
        a button here to copy the code to the clipboard.

      - Copy Authenticator Code to Clipboard - copies the code to the
        clipboard.


If implemented as I described above, then the user might have to move
past two additional items in the right-click menu.  But I don't think
there would be any additional clicks to create/use an entry unless the
user decided to use OTP for that entry.


Bill



[1] https://tools.ietf.org/html/rfc4226
[2] https://tools.ietf.org/html/rfc6238



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