PWG May 2021 Face-to-Face Meeting - Summary
May 13, 2021

The PWG held its May 2021 Virtual Face-to-Face Meeting on May 4-7, 2021 via Webex teleconferences. This event was held in collaboration with Linux Foundation OpenPrinting Workgroup. Sessions were presented by both organizations over the event's 4 days. Representatives from Artifex, Canon, Canonical, Google, High North, HP Inc., Konica Minolta, Kyocera Document Solutions, Lakeside Robotics, Lexmark, Microsoft, Qualcomm, Pharos, Red Hat, Ricoh, TIC, and TCS attended the meetings, among others. Attendees reviewed work in progress, including drafts of a number of in-progress specifications, and discussed liaisons with partner groups. Here is a summary of the proceedings.

PWG Plenary

The F2F event began with the PWG Plenary session, which had a reduced scope to limit the presentation time. The PWG Chair began with the new PWG Antitrust Policy, which was presented at the start of each session at this F2F, and will be presented at the start of all PWG teleconferences and F2F sessions going forward. The PWG Chair then reviewed the overall state of the PWG, its programs and initiatives, and briefly discussed upcoming face-to-face meeting scheduling. We noted that there are currently 692 printers certified under the PWG's IPP Everywhere™ Self Certification program. We discussed the PWG Steering Committee's activities and initiatives, including progress on Process 4.0, new policies, and recently approved documents. Officers from the IDS Workgroup and IPP Workgroup briefly summarized their Workgroup's status, and PWG Liaison Officers also briefly reported on the status of our partners' work in Mopria Alliance, ISO JTC1 WG12, and INCITS.

Complete minutes are available here:

Linux Foundation OpenPrinting Workgroup

The Linux Foundation OpenPrinting Workgroup held seven sessions on the first and second days, covering a variety of topics. On the first day in the OpenPrinting Plenary, Ira McDonald reviewed the Linux OpenPrinting project's accomplishments from 2020 and surveyed the efforts under way for 2021.

Following lunch, Aveek Basu (Lexmark / Linux Foundation OpenPrinting) presented a summary of the OpenPrinting Workgroup's activities during Google Summer of Code (GSoC) and Google Season of Docs (GSoD) events in 2020, and also the work being done as part of the Linux Foundation Mentorship Program (LFMP). Piyush Goyal presented a summary of his GSoD 2021 work on documentation for PAPPL Applications developers [link] to the group. Aveek concluded with a preview of the work planned for 2021 including attending Plumber's 2021 and engagement in the LFMP. Next, Michael Vrhel (Artifex) presented on the state of Ghostscript and MuPDF, covering two releases to Ghostscript and three releases of MuPDF. Other changes, security testing methodologies, and the status of a few other minor projects such as MuJS were also covered. Work planned for 2021 includes a new PDF interpreter in Ghostscript, Ghostscript device interface cleanup, resolution independent display list for Ghostscript, digital signatures, and ".docx" file format output for Ghostscript.

After a break, Sean Kau (Google) presented on the state of Chrome OS printing, reviewing the open source components used in the Chromium OS / Chrome OS printing system, including CUPS, cups-filters, Avahi, Ghostscript, and sane-airscan. Recent additions include expanded lpadmin errors and greater use of automated testing. New projects originated by the Google Chromium printing team include foomatic_shell, virtual-usb-printer, and ippusb_bridge, which is implemented in Rust. The presentation concluded with some discussion about scanning and the standards available today (eSCL and IPP Scan) and the desire for some additional features including "push scan".

On the second day, Mike Sweet (Lakeside Robotics) presented the CUPS Plenary, covering the changes that have occurred between Apple's "main" CUPS distribution and the OpenPrinting CUPS fork, which is seeing more active development. Mike is now coordinating code changes across the two distributions, with OpenPrinting CUPS pushing toward a 2.4.0 release. Apple will likely release a 2.3.5 release sometime in June 2021. CUPS 2.4 is expected to include many changes including shared printers reporting all required attributes/keys/values, OAuth 2.0/OpenID authentication, pkg-config support, snapcraft support, "job-sheets-col" and better "media-col" attribute support, TLS and X.509 improvements, and some new deprecations (cups-config and Kerberos authentication). Mike then reviewed the current plans for CUPS 3.0, which will be a profound change in architecture to previous CUPS releases. Much work is needed for this transformation to occur. Mike then presented on the state of CUPS Printer Applications, which are the successor to the legacy CUPS PPD / driver architecture. Mike has been working on the PAPPL framework for creating Printer Applications, and Till Kamppeter has been using this to create the new PostScript Printer Application. Till then presented a discussion of the details of the PostScript Printer Application, noting that it supports 4000 models based on PPDs from Foomatic and HPLIP. The project is nearly feature complete.

After lunch, Till presented an overview of the status of cups-filters, CUPS SNAP, IPP USB, and other projects. The cups-filters project is evolving with CUPS in many ways, including encapsulating filter binary functions within discrete library functions, reducing the overhead of spawning independent processes. The libppd and driverless utility projects were discussed. A major effort is underway to release CUPS as a Snap. Driverless scanning is also a major area of engagement by the OpenPrinting Workgroup currently, and the complexities of that effort were covered in detail. Implementation issues with IPP USB were also discussed. Till concluded with a discussion about GUI requirements.

Complete minutes are available here:

Internet Printing Protocol (IPP) Workgroup

IPP Workgroup sessions started on the second day of the F2F event with a status summary of IPP Workgroup activities currently in progress. IPP Everywhere v1.1 will become mandatory starting July 1, 2021. The IPP Everywhere Self Certification tools currently available are v1.0 update 5 and v1.1 update 2, with v1.1 update 3 hopefully available the week after the F2F event.

The IPP WG continued to discuss the evolution of IPP/2.0 and reviewed the initial draft of Internet Printing Protocol/2.x Fourth Edition (BASE). The discussion centered around the document's scope and how that relates to versioning and existing standards such as 5100.12 and STD 92. We then shifted to discuss scoping IPP Everywhere v2.0. We agreed "photo printing" is an important vertical solution that should be tested as a defined feature. We also discussed whether System Service should be included or not, and at what point we dedicate more energy to this, noting that we should first conclude our work on NODRIVER, EPX, and PPX.

On the third day, following the IDS session, we reviewed the new draft of IPP Encrypted Jobs and Documents v1.0 (TRUSTNOONE), which has been updated to incorporate S/MIME 4.0 (RFC 8551) and make that the primary required technology. OpenPGP will be left in but its description will be moved to an informative annex, making it an unofficial optional technology for TRUSTNOONE. Mike will announce it for more broad review once the new draft has been created.

We then had a Cloud Printing and Scanning BoF to generally discuss open next directions for INFRA and other PWG specifications to support these use cases for both 2D and 3D printing. We agreed that we needed to more clearly define the set of use cases for some of these general domains. Smith pointed out the OAuth 2.0 Device Authorization Grant and we agreed we should incorporate that into the range of options for registering a new IPP Proxy with a Cloud Print solution. We discussed some of the challenges with printing directly to a printer that is advertised via a cloud, and deferred discussion of IPP Scan enhancements until there are more examples of it being implemented in the field. We finished off the day by starting a review of the latest IPP Enterprise Printing Extensions v2.0. A number of changes were suggested.

On the last day, we began with a 3D Scanning and Production BoF, where we discussed file formats and their applicability to different important 3D scanning use cases, including acquiring point cloud data about an existing object and scanning a produced part for quality control. The E57 format is common for laser / LIDAR scanners but not used much for scanning smaller objects or for scanners that use cameras. The group speculatively agreed 3MF would be a good file format for 3D scanning that should satisfy both use cases.

After a break, we began a review of the latest draft of IPP Driverless Printing Extensions v2.0 (NODRIVER), which contains a resolution for the "print-quality" enhancements. Smith decided that Mike's proposal to encode this as an extension to "job-presets-supported" had some advantages over his own proposal. The group had a long discussion about the "print-processing-attributes-supported" attribute, which was basically the same as the earlier proposed "print-quality-hints-supported" attribute with a simplified definition and a new name. The discussion was productive and allowed the group to realize the value of some of the content present in earlier drafts that was removed. We then briefly reviewed the new draft of IPP Production Printing Extensions (PPX) which added the "job- phone-number", "job-phone-number-default", "job-phone-number-supported", "job- recipient-name", "job-recipient-name-default", and "job-recipient-name-supported" attributes that were removed from EPX. We concluded with Next Steps.

Complete minutes are available here:

Imaging Device Security (IDS) Workgroup

The Imaging Device Security session was held at the start of the third day. Al started by presenting the current status of the HCD iTC and its efforts to develop HCD cPP v1.0 and HCD SD v1.0. Additional comments had been submitted against the 2nd internal drafts of the HCD cPP and HCD SD to implement the recommendations of the Network Subgroup. The HCD iTC has spent the past few weeks completing the Security Problem Definition (SPD) and gathering feedback. A new Essential Security Requirements (ESR) document requirement, “The HCD shall verify the hardware-anchored integrity of firmware/software, including initial boot, operating system, and applications”, was added at the request of the HCD iTC. The HCD iTC formed a Hardware-anchored Integrity Verification subgroup to address this requirement. That subgroup developed a Secure Boot SFR (FPT_SBT_EXT) that addresses this ESR requirement and the subgroup will recommend to the full HCD iTC that it be added to the HCD cPP. The HCD iTC is now evaluating several SFRs including the NTP SFR, updates to the FPT_KYP_EXT Protection of Key and Key Material SFR from JBMIA, and feedback from the ITSCC on the ESR requirement “The HCD shall generate audit data, and be capable of sending it to a trusted external IT entity and store it in the HCD”. Al also discussed the deferred areas that the HCD iTC needs to engage on, and presented a proposal for a revised schedule, which puts completion in March 2022. He concluded the discussion about the HCD iTC with some thoughts on lessons learned over the last 14 months.

Al then reviewed the results of a discussion in a previous IDS Workgroup meeting with two members of the Massachusetts Department of Transportation (MASS DOT). One highlight of the discussion was that the MASS DOT members noticed that even when public interfaces are specified and in place for a long time, even if they are not correctly specified, they are very difficult to get changed because printer owners are concerned about unknown consequences to customers if configurations are changed. This is something that was new to many of us at the IDS meeting but is pretty well known to the IPP Workgroup.

Ira then covered the latest HCD Security Guidelines status. An updated draft was not published in time to be reviewed at this meeting, but Smith provided updates to the Wi-Fi content in Section 4 and Ira changed much of the guidance in Section 4 as a result. Ira plans to add some material on IPP to Section 4 as well. Ira says he plans to have a full-content update sometime in Q3 2021. The meeting concluded with Ira summarizing current standards development efforts in the Trusted Computing Group (TCG) and the Internet Engineering Task Force (IETF) that pertain to the IDS domain.

Complete minutes are available here: 

Next PWG Face-to-Face Meeting

The next PWG Face-to-Face meeting will be held August 17-19, 2021 via Webex teleconference. Be sure to subscribe to the mailing list to receive announcements about upcoming events and event changes or check the PWG Meetings page for updates on plans for upcoming meetings.

summarizing current standards development efforts in the Trusted Computing Group (TCG) and the Internet Engineering Task Force (IETF) that pertain to the IDS domain.

Complete minutes are available here: 

Next PWG Face-to-Face Meeting

The next PWG Face-to-Face meeting will be held August 17-19, 2021 via Webex teleconference. Be sure to subscribe to the mailing list to receive announcements about upcoming events and event changes or check the PWG Meetings page for updates on plans for upcoming meetings.