Why does presenting my credential to ten verifiers let them silently map my life?
機会
Every SD-JWT credential, the dominant format being deployed in EUDI Wallets across EU member states in 2026, carries a single issuer signature that is identical across all presentations. Any two verifiers who receive the same credential can share that token and link both visits to the same person. BBS+ with randomizable signatures prevents this correlation, but it is computationally heavier and production wallet support is thin. An IEEE EuroS&P 2026 paper confirms that issuer-verifier unlinkability is structurally impossible in salted-hash selective disclosure schemes like SD-JWT without issuing fresh credential batches per presentation, an operational burden no major deployment has solved. The hundreds of millions of wallets rolling out under eIDAS 2.0 today will silently correlate holders across every verifier they interact with for the lifetime of the credential.
重要な理由
Unlinkable presentation is the primitive that makes selective disclosure mean privacy rather than just granularity, and the dominant deployed format cannot provide it.
機会をどう評価するか
Opportunity Scoreは測定値ではなく、私自身の見解です。どれほど痛みを伴うか、どれほど頻繁に影響を与えるか、そして今日時点で解決策がいかに少ないか。スコアが高いほど、構築する価値が高いと私は考えています。
それが現れたときにどれほどの痛みをもたらすか。
実際にどれほど頻繁に人々がそれに直面するか。
今日時点で、それに対する優れたツールがいかに少ないか。