IdentitySign: Design and User Study of a Prototype Application for Digitally Signing Documents Using an Identity Wallet When signing digital documents, users often insert scanned or digitized handwritten signatures, which provide no assurance of a document’s authenticity and integrity. Cryptographic signatures offer such guarantees, but are rarely adopted due to persistent usability challenges. This paper explores the potential of digital identity wallets for securely and intuitively signing documents with verified personal data. To this end, we developed IdentitySign, an open-source prototype application, and evaluated it through a user study (N=74). Our results indicate good usability but also reveal potential pitfalls for this and similar wallet-based signature applications, such as unjustified trust in documents with signatures that are cryptographically valid but signed by the wrong signer. We provide guidelines and insights for creating user-centric, secure, and trustworthy digital signage applications using identity wallets.