STIR/SHAKEN display standards are emerging

The STIR/SHAKEN standards did not dictate how verification service (STI-VS) results should be displayed for users. This has been under discussion for a while, and standards are emerging.

Requirements

Consistent patterns for display would help users to understand the presentation across all devices they encounter. This would help users learn what to expect and appreciate the benefits of verification status information.

Display is easier on smartphones because there’s lots of screen area and a fully graphical interface. The expectation is that software developers will enhance the handset software to use the verstat parameter in the SIP INVITE and format the presentation of incoming call data appropriately.

Capabilities are limited on legacy phones and caller ID displays, which may support only 15 characters from the printable ASCII character set. The expectation is that the verification software (STI-VS) will update the caller display name with information to reflect the outcome of STIR/SHAKEN processing.

Printable ASCII characters

Therefore, the discussion is converging on an approach that would work for a wide array of equipment.

Possible outcomes and recommended display

The display patterns are based upon the results of three analyses:

1. STI outcome
2. Call analytics (e.g., phone number reputation lookup) outcome
3. Whether there is a privacy header in the SIP message

The following table describes the recommended displays according to results of these analyses:

STI outcome	Reputation	Privacy header	Digital display	Character display
Verified	Good	No	Caller ID	[V]Caller ID
Verified	Good	Yes	Anonymous	[V]Anonymous
Verified	Poor	Yes or No	<SPAM>	[V]<SPAM>
Failed or no token	Good	No	Caller ID	Caller ID
Failed or no token	Good	Yes	Anonymous	Anonymous
Failed or no token	Poor	Yes or No	<SPAM>	<SPAM>

Notice that, with a character display, successful verification uses only three of the 15 characters available, leaving 12 characters to display caller ID on legacy phones and caller ID displays.

If the calling number has a poor reputation, then the <SPAM> display uses six characters, but the caller ID is suspicious anyway. The logic is that it won’t hurt to use that many characters.

TransNexus approach

Our TransNexus STIR/SHAKEN solutions modify the caller name as described in character name display values above. (Digital display presentation is left to handset software developers, who will likely present results according to the verstat parameter.)

TransNexus STIR/SHAKEN solutions

STIR/SHAKEN functionality is available in our ClearIP and NexOSS software products. These comprehensive solutions include authentication, verification and certificate management. In addition, features are available for flexible, granular policy setting to control attestation and call handling according to STIR/SHAKEN outcomes.

Contact us today to learn how we can help you deploy your STIR/SHAKEN solution.