@techreport{ietf-stir-certificate-transparency-05,
    number =    {draft-ietf-stir-certificate-transparency-05},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-ietf-stir-certificate-transparency/05/},
    author =    {Chris Wendt and Robert Śliwa and Alec Fenichel and Vinit Anil Gaikwad},
    title =     {{STI Certificate Transparency}},
    pagetotal = 16,
    year =      2026,
    month =     oct,
    day =       21,
    abstract =  {This document describes a framework for the use of the Certificate Transparency (CT) protocol for publicly logging the existence of Secure Telephone Identity (STI) certificates as they are issued or observed. This allows any interested party that is part of the STI ecosystem to audit STI certification authority (CA) activity and audit both the issuance of suspect certificates and the certificate logs themselves. The intent is to establish a level of trust within the STI ecosystem that relies on the verification of telephone numbers. This involves requiring STI certificates to be listed in an established log and refusing to honor those that are not. This effectively establishes the precedent that STI CAs must add all issued certificates to the logs and thus establishes unique association of STI certificates to an authorized provider or assignee of a telephone number resource. In the STI ecosystem, the primary role of CT is to provide verifiable trust by detecting the unauthorized issuance of duplicate telephone number level delegate certificates or provider level certificates. This provides a robust auditable mechanism for the detection of unauthorized creation of certificate credentials for illegitimate spoofing of telephone numbers or service provider codes (SPC). The framework borrows the log structure and API model from RFC6962 to enable public auditing and verifiability of certificate issuance. While the foundational mechanisms for log operation, Merkle Tree construction, and Signed Certificate Timestamps (SCTs) are aligned with RFC6962, this document contextualizes their application in the STIR ecosystem, focusing on verifiable control over telephone number or service provider code resources.},
}