---
title: "Verifying your age in a privacy preserving manner"
url: https://daily.dev/posts/verifying-your-age-in-a-privacy-preserving-manner-bt6nvpq9g
source_url: https://adayinthelifeof.nl/2026/04/27/sd-jwt.html
type: article
source: "A Day in the Life Of"
published: 2026-04-27T10:56:59.436Z
updated: 2026-05-07T02:14:01.112Z
tags: ["authentication", "jwt", "privacy", "zero-knowledge-proofs"]
reading_time: 6
upvotes: 0
comments: 0
language: en
---

> ## Documentation Index
> Fetch the complete documentation index at: https://daily.dev/llms.txt
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# Verifying your age in a privacy preserving manner

**[A Day in the Life Of](https://daily.dev/sources/adayinthelife)** · 6 min read · 0 upvotes · 0 comments

## Summary

Selective Disclosure JWT (SD-JWT) offers a privacy-preserving approach to age verification. Instead of sharing full identity documents, a government or trusted issuer signs a JWT containing only hashes of individual claims (e.g., age_over_18, birthdate, country). When a website asks if a user is old enough, the user reveals only the specific disclosure — the salt, claim name, and value — for that one claim. The verifier reconstructs the hash and checks it against the JWT, confirming the claim without learning anything else. Drawbacks include potential cross-site correlation if the same credential is reused, and the inability to answer questions not pre-baked into the credential (e.g., 'is user over 25?'), which would require zero-knowledge proofs.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://adayinthelifeof.nl/2026/04/27/sd-jwt.html>

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---

Tags: [#authentication](https://daily.dev/tags/authentication), [#jwt](https://daily.dev/tags/jwt), [#privacy](https://daily.dev/tags/privacy), [#zero-knowledge-proofs](https://daily.dev/tags/zero-knowledge-proofs)

[View this post on daily.dev](https://daily.dev/posts/verifying-your-age-in-a-privacy-preserving-manner-bt6nvpq9g)