WYSIWYS

WYSIWYS ensures the document you see when signing matches exactly what is hashed and signed, protecting signer intent and legal validity.

WYSIWYS is the principle that the document a signer views on screen must be exactly the same content that is hashed and cryptographically signed. If the displayed version and the underlying data differ, for example due to a mismatched file format or hidden content, the signer's consent no longer matches what is actually signed. This is hardest to guarantee in remote signing, where the signing key is held by a QTSP rather than on the signer's own device, and is addressed through signature activation data and a trustworthy signature creation application that binds the displayed document to the data that actually gets signed.