1: What I understand, the ICAO master list and the EU master list is the most 
trustworthy source of data today. What I understand the private sector pilot is 
about allowing private sector systems to become authorized inspection systems 
with fingerprint. This could also become a additional way to verify users using 
a desktop fingerprint reader.

 

2: I know that. Thats why I suggest a system where a biometric face scan with 
liveness check, is done, which is then linked to a secure hash of the passport 
object AND the ACME account.
These two strong links ensures that:

a: The passport is not replaced with another passport (to use the approved 
biometric scan to approve a passport that is not yours)

b: to ensure passport is not stolen.

Basically, the biometric scan tells us that ”ACME account A is authorized to 
use passport represented with hash(B) a unlimited number of times”.

This means no personal data needs to be stored, and thats why you have to 
resubmit validation for every renew.

 

The biggest problem with chip authentication and active authentication, is as I 
mentioned, not all countries procure chips with CA/AA support enabled. My 
current passport have the AA flag unset, it says ”Active authentication: NOT 
PRESENT/NOT SUPPORTED”, meaning replay attacks cannot be prevented.

Requiring AA or CA for authentication risk excluding many people just because 
their passport issuer didn’t procure the ”right chips”.

 

3: My idea is that its up to the CA to decide how long they want to trust the 
data and how they want to check against CRLs. Nothing prevents the CA from 
storing just the certificate serial of the passport for example.

Since the linking to ACME account is so strong, I see that the biometric 
authentication can be valid for the life of the passport. Its locked to ACME 
account, which is secure enough.

 

4: Authentication via eIDAS is already approved today according to CAB.

However, theres two problems with eIDAS.

 

First, is that its very costly to enroll in eIDAS. Some country might allow you 
to enroll for free, but partipicating countries may not always accept these 
free providers due to the risk of fraud if theres no payable business identity 
behind.

With ”enroll” here, im talking about accepting ID cards. Using a ID card in 
eIDAS is always free.

 

Second, it cannot be automated. It would require a manual action for each renew.

eIDAS could be a system that could replace the biometric authentication in 
certain stuations -->

Where eMRTD data is used to authorize a renew, while the eMRTD data + eIDAS 
data is verified once with PIN code or other authentication factor to ”approve” 
the ACME account to make unlimited renews with the very same eMRTD.

 

 

The biggest advantage with eMRTD is that its free, anyone with some software 
code, the right public keys, and a NFC scanner, can scan a passport, and fetch 
all the data on it, including the picture (to make a biometric comparision), 
all the data printed on passport, and some additional info. Only thing that is 
restricted is the fingerprint, that requires terminal authentication.

Thats the biggest advantage, which means the friction for a CA to inplement it, 
with a fully automated validation solution where no human need sto approve the 
issuance (like lets encrypt) is very low, and it will drive down the prices for 
IV certificates.

 

 

Från: [email protected] <[email protected]> För Ave Özkal
Skickat: den 23 mars 2026 18:49
Till: [email protected]
Ämne: [Acme] Feedback on EMRTD-DATA-01

 

Hello all,

I'm Ave Özkal. I'm not working for any CA, and have no WG experience, however I 
have implemented ICAO 9303 (the standard for MRTD/eMRTDs) several times for OSS 
projects (it was my covid lockdown hobby) and have some close familiarity with 
it.

I read the slides on EMRTD-DATA-01 
<https://datatracker.ietf.org/meeting/125/materials/slides-125-acme-emrtd-data-01-00>
 , assembled a list of thoughts and concerns, and contacted Mike Ounsworth with 
them earlier. He suggested I also send them here, so I summarized them a bit 
and corrected for some mistakes I made.

---

The situation with document validation itself is complicated, and is done 
against each country's PKI rather than that of ICAO, unlike what the slides 
imply.

A complete validation of data accuracy requires:
- (Ideally) reading all files available to current authentication level
- Validating hashes of the documents against the directory file
- Checking the signature of the document against the document signer 
certificate, and the document signer certificate ("DSC") against the country 
signer certificate authority certificate ("CSCA certificate"). See 
https://www.icao.int/icao-pkd/epassport-basics

(Plus validation against the biometric picture and comparing the full name 
against what was stated in the CSR. These are both among the files in the 
document.)

ICAO kindly publishes a PKD ("Master List"), but not all countries are choosing 
to take part in this, currently 107 out of 193 UN-recognized countries are 
members of this program: https://www.icao.int/icao-pkd

The current terms also bar commercial usage: https://download.pkd.icao.int/

However there is a pilot program to allow private sector users, and it may be 
worthwhile to contact ICAO to hear if they think they'll roll this out, what 
their timelines are, and if they'd be willing to allow CAs into such a program 
once it goes GA: https://www.icao.int/icao-pkd/private-sector-pilot

If I recall correctly from my own, non-commercial experiences, obtaining 
Document Signer Certificates was also not always straightforward for all 
participating countries, but I may have missed something obvious here. Not all 
countries had a publicly available CRL/OCSP endpoint for DSCs, if I recall 
correctly. It's a point that's worth looking into, and it may be worthwhile to 
codify into requirements for public CAs that this standard may only be utilized 
for documents from countries participating in ICAO's PKD and retain a public 
CRL/OCSP for DSCs.

I believe it would be worthwhile to still try to rely on ICAO's PKD rather than 
requiring CAs to obtain CSCA certs through other means (e.g. some countries 
publish it on a website for the CSCA), as ICAO assures that the certificates 
are received through diplomatic channels.

---

There's insufficient protections against replay attacks within the proposal.

An eMRTD can be thought of as an authenticated, signed data store, with most of 
the protection against cloning coming from the need to forge a real-looking 
document. I have a copy of my passport's data within a folder in my computer.

There are two primary methods to validate that there's a real eMRTD, Chip 
Authentication and Active Authentication. Not all countries support them across 
all documents. Sometimes countries change providers and the chip/active 
authentication support is lost in the process. (I want to include a note to 
thank the friend who was the first to point out that these are lacking from the 
proposal when we were looking at the slides.)

The original proposal 
<https://groups.google.com/a/groups.cabforum.org/g/servercert-wg/c/mzoJV9tsV-0?pli=1>
  mentions Chip/Active authentication, but explicitly excludes it as it's not 
widely or continuously deployed. In my opinion, this is a necessary compromise 
to achieve sufficient liveness checks for the eMRTD.

---

I am of the opinion that public CAs deploying this standard for longer validity 
certificates would benefit from storing the document details and certificate 
for the duration of its validity, with a regular automated check of the 
certificate against the country CRL/OCSP, and the document number(/type/etc) 
against the Interpol database of lost and stolen documents, specifically the 
I-Checkit program made available to private sector partners: 
https://www.interpol.int/How-we-work/I-Checkit

This is a downgrade in privacy, but in my opinion this is a necessary safeguard.

---

An alternative, smaller scale approach that came to mind would be to build such 
an ACME standard for identity validation with EU's eIDAS, in case it gets 
decided to not pursue this standard.

eIDAS is a requirement on all EU ID cards, and all EU countries except Ireland 
and iirc Denmark issue ID cards to all citizens. I believe EU residence permit 
cards tend to support eIDAS as well. eIDAS has further mechanisms to handle 
identity verification and document validity checking, alongside built-in 
liveness checking and a requirement to insert a PIN (reducing risk from stolen 
documents). If I recall correctly, it only requires approval from one country 
to integrate with the entirety of the union.

(It's also a completely different proposal than this one and only covers ~500 
million people in (excluding emigrants) one continent.)

 

Best regards,
Ave Özkal

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