Rich Call Data and caller identity

The FCC has requested comment on ways to provide accurate caller name information to call recipients for calls authenticated with full A-level attestation. Rich Call Data (RCD) is well suited to this task, and there has been work underway to refine how it can be used. With the FCC’s request for comment in play, now is a good time to review these refinements.

The STIR/SHAKEN framework is used to convey a digitally signed assertion of the caller’s identity, which is represented as the caller’s telephone number. Identifying the caller by name was outside the scope of the initial framework.

However, there can be tremendous benefits to including additional authenticated information about the caller, such as the caller’s name, in the authentication framework. This is a primary goal in branded calling.

Since the originating service provider authenticating calls with a full A-level attestation must have a direct authenticated relationship with the customer and be able to identify the customer, it is also ideally situated to include the customer’s name and other vetted information in the digitally signed assertion of the caller’s identity.

The processes for doing this are described in ATIS and IETF documents. Work has been underway to improve the IETF document. This article will review the changes.

ATIS standard on Rich Call Data

Rich Call Data is described in ATIS-1000094, Calling Name and Rich Call Data Handling Procedures. This standard was approved on April 12, 2021.

There’s a lot of interesting information in the standard, but the basic idea is easy to understand: just add an “rcd” claim to the PASSporT with a key-value pair representing the caller’s name. Here is an example:

"rcd":{"nam":"Dentist Office"}

This is an rcd claim in which the caller’s name is identified with a “nam” key as “Dentist Office.”

That’s it. Fairly simple, yes?

The ATIS standard also describes fancier, more complex uses of RCD, such as:

• jCards, which support a wide range of caller information, either embedded in the PASSporT or externally hosted.
• Call reason, which is a text field to explain the call. (This “crn” claim is separate from the rcd claim.)
• An rcd PASSporT, which is a base PASSporT populated with rcd and optional crn claims. An rcd PASSporT can either be created by a SHAKEN OSP and signed with their SHAKEN credentials or by a non-SHAKEN VoIP entity and signed with their delegate certificate.

However, the simple version described above is an ideal solution to provide a secure, digitally signed, vetted caller name.

The ATIS RCD standard does not mandate a mechanism for the terminating provider to convey the caller’s name to the call recipient but leaves it to local policy and capabilities. For example, the terminating provider might copy the rcd nam value to the display name portion of the P-Asserted-Identity and/or From header field.

As you can see, adding RCD information to include an authenticated caller name is easy. We’ve supported this feature in our software since 2019.

IETF draft standard

There’s ongoing work to develop an IETF standard for RCD. The draft IETF standard has been updated periodically since it was first introduced in 2016. The ATIS-1000094 standard on RCD lists this IETF draft as a normative reference.

Here are a few notable updates found in the draft IETF document:

• “icn” (icon) is a new optional rcd claim key whose value provides a URL for an image resource. This is a simple alternative to using a jCard to display an icon image.
• “apn” (alternate presentation number) is a new optional rcd claim key whose value provides an authenticated and vetted number to display as the calling number. For example, this could be used to present an enterprise main number rather than the caller’s personal telephone number.

FCC request for comments

The FCC asked for comments on accurate caller name in their Further Notice of Proposed Rulemaking, paragraphs 95–100, from May 18, 2023. In their FNPRM, the Commission noted that:

• Combining caller name with a full attestation indication could provide real benefit to consumers.
• Caller name information is only valuable if it’s accurate.

The Commission asked several questions about RCD and whether it would be a better choice for caller name display versus a technology-neutral alternative. Comments are due August 9, 2023.

TransNexus solutions

TransNexus is a leader in developing innovative software to manage and protect telecommunications networks. The company has over 20 years’ experience in providing telecom software solutions including toll fraud prevention, robocall mitigation and prevention, TDoS prevention, analytics, routing, billing support, STIR/SHAKEN and SHAKEN certificate services.

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