Feature idea — instructor/guide validation and signature on a dive

[Federico Boni]

Hello everyone,

I'm a technical diver and developer working with a dive center in Italy, and I'd like to float an idea before opening a GitHub issue, in case there's interest.

The idea: an optional per-dive "validation" block, where a guide or instructor confirms the dive. It would hold a name, an identifier (certification or registration number), the dive center name, a timestamp, and a signature captured on the touchscreen in Subsurface-mobile.

Why this is useful beyond one country:

- Instructor-signed logbooks are standard practice across all training agencies. Divers routinely need a validated log to qualify for the next course level, and today that still means a paper logbook alongside the digital one.
- Dive centers and guides have a liability interest in a record of who supervised which dive.
- It's becoming a legal requirement in at least one jurisdiction. Italy passed Law 70/2026 in May, which mandates a dive logbook with specific fields for recreational diving. Subsurface already records almost all of them (date, site, start and end time, breathing mixture, max depth reached). What's missing is planned max depth, the dive center name, and the instructor's details — exactly the block described above.

On storage, my concern is round-trip safety: a new field would need to be handled in both the XML and the git storage formats, otherwise it would be silently dropped when a log is opened and saved by an unmodified build. An alternative that avoids touching the formats at all would be to build this on top of the existing extra_data key/value mechanism, which already round-trips cleanly.

On the signature itself, storing a compact stroke path rather than a raster image would keep the git repository small. There may also be a privacy argument for keeping only a hash in the log — signatures belong to a third party, not the log owner.

I'm not asking anyone to do this for free and walk away. I can provide the exact legal requirements and field list, test builds against real dive center data over a full season, and help with the Italian translation. If someone is willing to look at it, I'm happy to do the unglamorous parts.

Happy to hear if this is of interest, or if it's out of scope for the project.

Thanks for Subsurface — it's what I use every day.

Federico, Rio Saliceto , Italy

[Michael Keller]

Hi Federico.

Thank you for the thoughtful proposal and for offering to help with the implementation and testing.

Have a look at this earlier discussion of much the same idea:

https://groups.google.com/g/subsurface-divelog/c/UNKFu0ciu_0/m/hwqX0X_UDAAJ

The central difficulty is not just storing the additional fields. A captured signature does not establish who provided it, whether they consented to its use, or whether the dive record was modified afterwards. Subsurface does not have the identity and trust infrastructure needed to provide that assurance.

Regarding Law 70/2026, the Subsurface project could not reasonably certify that the application or its records comply with a particular law. Adding the fields specified by the law would not, by itself, establish legal compliance. We would still need to make clear that users are responsible for determining whether their records meet the applicable legal requirements.

For now, the practical approach would be to record the additional Italian information using the existing Guide, Buddy and Notes fields, and attach an image of the signed record to the dive. That does not itself guarantee compliance, but it captures the information without adding country-specific fields and signature handling that would not be relevant to most Subsurface users.

Ngā mihi

  Michael Keller

--
You received this message because you are subscribed to the Google Groups "Subsurface Divelog" group.
To unsubscribe from this group and stop receiving emails from it, send an email to subsurface-dive...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/subsurface-divelog/569e7fc2-8a41-4ae9-a71b-fa943f387286n%40googlegroups.com.

--

GCS$/CC/E/IT d- s+ a C++ UL+++/S++ P L++ E-
W++ N o? K? w O(++) M-- V+ PS+ PE+ Y? PGP+ t
5? X R tv b++ DI++ D++ G e+++ h---- r+++ y+++

[Edward Haynes]

Hi,

Though instructor signatures and identification sounds good. I don’t think it meets the developing trend of on-line agency sign off. 

For example BSAC instructors now sign off lessons etc via the BSAC management system, not via a physical logbook. Evidence on lessons and dive qualifications are now available to the individual through their MyBSAC account; only the instructor number is displayed.

Kind regards 

Edward Haynes

DO Fyne-divers

+44 (0) 7800 590112

BSAC

Dive with us

On 27 Aug 2026, at 10:15, Michael Keller <m...@042.ch> wrote:



To view this discussion visit https://groups.google.com/d/msgid/subsurface-divelog/CACJC9LYLZwXiG%2BFGEKP%2BVjkAMmrBM0OoSc%3DviS-y-ANJMkFgaQ%40mail.gmail.com.

[Federico Boni]

Hi,

I understand your point, but that way each training agency handles things differently. Since I am a RAID instructor/guide working at a dive center, if I had to guide divers certified by other agencies, I wouldn't be able to sign their digital logbooks.

Instead, if there could be a signature feature using a finger on the screen, or via a QR code (which almost every agency now assigns to its professionals)...

[Edward Haynes]

Hi Federico,

The MyBSAC account only records BSAC course lessons and qualifications signed off by BSAC instructors. One of the reasons the system was introduced was to stop items being signed off by non-BSAC and expired BSAC instructors. As an added bonus we now know who are our active instructors are. 

The system used by an individual to record their fun diving is not mandated by BSAC.

Kind regards 

Edward 

Edward Haynes

DO Fyne-divers

+44 (0) 7800 590112

BSAC

Dive with us

On 27 Aug 2026, at 14:29, Federico Boni <ondanom...@gmail.com> wrote:



To view this discussion visit https://groups.google.com/d/msgid/subsurface-divelog/14213eb0-9f71-4dbd-8dd1-78c3e2c352adn%40googlegroups.com.

[Dirk Hohndel]

I'm not sure you actually understand our point.

The Subsurface maintainers have consciously decided that we are not interested in implementing (or having someone submit an AI implementation of) a signature feature.

We don't believe that this is something that we want to wade into, as a "signature" can have legal meaning in different countries, can have contractual meaning with different agencies, and unless there is a trust framework around it, any implementation you add is meaningless (you can just as easily type in "Frederico signed off on this dive" in the notes field).

So while I appreciate that some users disagree with us, those users are always welcome to write their own software or use a different dive log that better matches their needs.

Subsurface does not and will not support the concept of "signatures" on dives.

Thanks

/D

To view this discussion visit https://groups.google.com/d/msgid/subsurface-divelog/14213eb0-9f71-4dbd-8dd1-78c3e2c352adn%40googlegroups.com.

[Edward Haynes]

I agree, in the U.K. images of signatures attached or imbedded into documents are legally binding.

There are also data protection issues.

Edward Haynes

DO Fyne-divers

+44 (0) 7800 590112

BSAC

Dive with us

On 27 Aug 2026, at 18:05, 'Dirk Hohndel' via Subsurface Divelog <subsurfac...@googlegroups.com> wrote:

I'm not sure you actually understand our point.

To view this discussion visit https://groups.google.com/d/msgid/subsurface-divelog/D64A64BB-A2A3-4156-90E6-F9E339865714%40hohndel.org.