What technical methods let platforms verify age without collecting ID documents?
A promising approach is Biometric Bound Credentials (BBCreds), proposed in a 2025 paper [2]. This system cryptographically binds an age credential to a user's biometric features—like a fingerprint or face scan—without ever storing the actual biometric template. That means the platform can confirm the user is the legitimate holder of the credential and is physically present, but it cannot reconstruct or misuse the biometric data. The credential itself proves the user is old enough, not who they are, so no government ID or passport is needed.
The key advantage is that BBCreds prevent credential sharing (a minor can't hand their older sibling's credential to a friend) while keeping the user's identity private. The 2025 paper [2] explicitly states this approach 'enhances privacy' and addresses both legacy problems (poor accuracy, security risks) and emerging concerns (surveillance, fairness). This is the only technical solution detailed in the provided papers that directly answers the question of how to restrict minors without identity documents.
Why aren't privacy-friendly methods like BBCreds already in widespread use?
The main obstacle is not technology but policy and trust. A 2024 study [1][3] examined government laws worldwide and found that most countries are using a 'responsibilization strategy'—they push the burden of age verification onto platforms without specifying how to do it privately. This has led to a split: some platforms deploy 'privacy-invasive' methods (like scanning passports or uploading ID photos) that violate minors' privacy, while others use 'ineffective' methods (like simple self-declaration of age) that are easily bypassed. The study [1] concludes there is 'a general lack of privacy preservation and affordable technological solutions' in current deployments.
Furthermore, the same study [1][3] surveyed UK public opinion and found 'general disengagement and a lack of trust in the government' regarding new age verification laws. If the public doesn't trust the system, they may resist or circumvent it, undermining the entire goal of protecting minors. So even when a privacy-preserving technical solution like BBCreds exists, it won't be adopted unless governments mandate privacy standards and platforms invest in implementation—and the public believes the system works.
Do current no-ID age verification methods actually work?
The evidence from the 2024 study [1][3] is blunt: current methods are either privacy-invasive or ineffective, and neither serves the goal of protecting minors. The study found that 'the overarching aims of the online safety and age verification legislative changes may not be satisfied' due to public disengagement and lack of trust. In other words, even if a platform uses a method that doesn't collect ID (like a simple age gate), it's likely too easy for minors to bypass. If it does collect ID, it violates privacy.
The 2025 BBCreds proposal [2] is not yet deployed at scale, so there is no real-world data on its effectiveness. But it represents a clear technical path forward: it can verify age without ID, prevent sharing, and protect privacy. The gap between this best-case technical solution and the typical-case reality of invasive or broken systems is the central challenge highlighted by all three papers.
About These Sources
This answer is built on 3 studies (2 peer-reviewed, 1 preprint) — published from 2024 to 2025, 3 from 2024 or later, 1 in Q1 journals — selected as the most relevant from 3 studies that passed quality screening, drawn from 37 papers retrieved from a database of over 500 million.
Sources used in this answer
Online Age Verification: Government Legislation, Supplier Responsibilization, and Public Perceptions
A 2024 study of global age verification laws found that governments push responsibility onto platforms, leading to either privacy-invasive or ineffective methods, and that UK public trust in these systems is low.
Biometric Bound Credentials for Age Verification
A 2025 paper proposes Biometric Bound Credentials (BBCreds), which cryptographically bind age credentials to biometric features without storing templates, enabling privacy-preserving age verification without ID documents.
Online age verification : government legislation; supplier responsibilization; public perceptions
A 2024 repository version of the same study confirms that current age verification laws lack privacy-preserving and affordable solutions, and that public disengagement threatens the laws' effectiveness.