Minutes IETF126: webbotauth
minutes-126-webbotauth-00

**Session Date/Time:** 22 Jul 2026 07:00

# WEBBOTAUTH

## Summary

The WEBBOTAUTH Working Group met at IETF 126 in Vienna. Co-Chairs Raffat and
David Schinazi presided. The session focused on the two parallel paths
established at the April interim meeting for web bot authentication: 1.
**Identifying Bot Authentication**: Cryptographically identifying bots. 2.
**Anonymous Bot Authentication**: Demonstrating bot properties without
revealing specific identity.

The group also discussed crawler best practices as an informational/operational
item.

---

## Key Discussion Points

### 1. HTTP Message Signatures for Automated Traffic
Thibault Meunier presented the individual draft on this topic.
* **Slides**: [HTTP Message Signatures for automated
traffic](https://datatracker.ietf.org/meeting/126/materials/slides-126-webbotauth-http-message-signatures-for-automated-traffic-00)
* **Overview**: The proposal leverages RFC 9421 (HTTP Message Signatures) to
establish bot trust continuity over time. It operates in two modes using the
same wire format: an **opaque mode** (using a key ID/pseudonym as an anchor)
and a **domain binding mode** (anchored on WebPKI/TLS well-known directories).
The latest revision removes the inline data URI key option. * **Discussion**:
  * **Key Discovery and Rotation**: Eric Rescorla pointed out that both opaque
  and domain-bound modes ultimately require fetching keys from a URI over TLS.
  He suggested that using the URI itself as the identifier would preserve key
  rotation while maintaining pseudonymity. Justin Richer agreed that key
  discovery and signature verification should be clearly layered, noting that
  HTTP Message Signatures intentionally excluded fetchable key discovery due to
  differing trust semantics. * **Signature Construction**: Justin Richer
  flagged that signing a signature value is a known cryptographic risk and
  offered to help the authors align the application of HTTP signatures with
  best practices. * **General client identity**: Dick Hardt supported the
  direction but suggested aligning this with a general-purpose HTTP client
  identification mechanism in the HTTP working group (HTTPBIS) rather than
  keeping it strictly specific to bots. * **Voluntariness and Access Risks**:
  Eric Nygren, Richard Barnes, and Alissa Cooper raised concerns that while the
  system is designed to be voluntary, in practice it may become a de facto
  requirement to access web content, potentially leading to a discriminatory
  web or balkanization. Marwan Fayed countered that without such a standard,
  operators will continue to block unrecognized traffic anyway, making a
  standardized path necessary to preserve open access.

---

### 2. Anonymous Bot Authentication
Eric Rescorla presented the anonymous authentication path, which relies heavily
on the emerging "MOLE" (Modulated Oblivious Logarithmic Evaluation)
architecture. * **Slides**: [Anonymous Bot
Authentication](https://datatracker.ietf.org/meeting/126/materials/slides-126-webbotauth-anonymous-bot-authentication-01)
* **Overview**: Under this model, third-party "anchors" vouch for bots and
issue "endorsements." When interacting with a site's "moderator," the bot
trades the endorsement for a "credential." The credential carries a token
budget used to rate-limit or penalize abusive bots while keeping their specific
identities unlinkable and private. * **Discussion**:
  * **Anchor Incentives and Centralization**: Pablo González and Ted Hardie
  raised concerns about the centralization of power in anchors and whether
  enough distinct entities would have the incentive to act as anchors. Jonathan
  Hoyland noted that if sites only trust large anchors (e.g., Google or
  OpenAI), small bots will lose the ability to remain anonymous. Samuel
  Schlesinger suggested that the site moderators, rather than the anchors,
  should bear the primary burden of rate-limiting and reputation management. *
  **Concurrency**: Pablo González questioned how concurrency is handled, given
  that updating credentials takes time. Eric Rescorla suggested a multi-tier
  approach, such as using a session cookie for subsequent requests to avoid
  constant cryptographic updates. * **Information Leakage**: Daniel Kahn
  Gillmor and Martin Thomson discussed whether relying parties could
  distinguish between humans and bots based on anchor subsets, noting that if
  too many attributes are disclosed, it creates fingerprinting vectors that
  undermine anonymity. * **Durable Identifiers vs. Endorsements**: Dick Hardt
  argued that site-specific, random durable identifiers are simpler and more
  effective for building reputation based directly on behavior, rather than
  relying on complex third-party anchor endorsements.

---

### 3. Crawler Best Practices
Gary Illyes presented on documenting the de facto operational conventions of
web crawlers. * **Slides**: [Crawler Best
Practices](https://datatracker.ietf.org/meeting/126/materials/slides-126-webbotauth-crawler-best-practices-00)
* **Overview**: The document outlines baseline requirements for bot hygiene,
including compliance with robots.txt (RFC 9309), rate control, backoff signals,
identity transparency, and IP address distribution. * **Discussion**:
  * **WG Scope**: Co-chair David Schinazi noted that while this is technically
  outside the current WEBBOTAUTH charter, it could be discussed or eventually
  adopted if the charter is adjusted. Justin Richer strongly supported
  adoption, comparing it to the workload identity practices document in the
  WIMSE WG (`draft-ietf-wimse-workload-identity-practices-05`). * **Adversarial
  Application**: Eric Rescorla cautioned that such a BCP could be used as a
  "club" by sites to enforce behavior that is adversarial to legitimate
  scraping efforts (e.g., consumer protection bots). Mark Nottingham suggested
  focusing strictly on areas of solid consensus to avoid contentious
  recommendations. * **Charter Fit**: AD Mike Bishop pointed out that the
  current charter already includes a milestone for BCP and/or informational
  documents describing operational considerations, meaning the work is likely
  close enough to proceed. Mirja Kühlewind advised a formal recharter to avoid
  IETF Last Call issues.

---

## Decisions and Action Items

### Polls
The chairs ran a single poll regarding the identifying approach ("HTTP Message
Signatures for automated traffic") to gauge group consensus on the starting
direction:

* **Question**: *Do we think this is the right general direction / starting
point?* * **Results**: **Yes: 22**, **No: 6**, **No Opinion: 5** (Total
participants: 75)

### Actions
* **HTTP Message Signatures Draft**: The authors (Thibault Meunier et al.) will
continue refining the draft to address key discovery, key rotation semantics,
and cryptographic feedback regarding signature structures before seeking formal
adoption. * **Anonymous Draft / MOLE Integration**: The anonymous bot draft
will remain in an exploratory stage, tracking the progress of the MOLE/MOUE
drafts. Interested participants were encouraged to join the Moll mailing list.
* **Crawler Best Practices**: Discussions on the crawler best practices
document (`draft-farzdusa-webbot-datacollection` was also noted in chat by
Farzaneh as relevant) will continue on the mailing list. The chairs and AD will
coordinate on whether a minor recharter is required to adopt it.

---

## Next Steps
* Detailed review of the signature mechanics in the identifying draft by Justin
Richer and other security experts. * Continued collaboration with the MOLE
design team to refine the anonymous bot authentication flow. * The chairs will
evaluate organizing an interim virtual meeting before IETF 127 in November (San
Francisco) to maintain momentum.