iHDoc: Secure NFC Mobile-based Digital Document Signatures Prototype

Digital signatures are essential for secure data interchange. However, most document signing solutions depend on cloud-based infrastructures, which may expose users to security vulnerabilities and significant computational requirements. This paper proposes designing and implementing a proximity mobile-based iHDoc digital document signing prototype to sign documents over a Near Field Communication (NFC) tap. It consists of Signer and Signee applications on two different mobile devices that tap to first mutually authenticate each other and then sign the document. iHDoc utilizes iDSign, a previously proposed secure and lightweight design framework based on Identity-based Cryptography (IBC). IBC eliminates the need for certificates by associating public keys directly with user identities, reducing computational and communication overhead and assisting in lightweight mutual authentication over HCE and resource-constrained mobile devices. NFC proximity reduces the risk of man-in-the-middle attacks and ensures the locality of reference. Performance comparison of iHDoc with IBC and RSA-based mutual authentication indicates that the iHDoc prototype performs better with iDSign due to reduced time and storage. It is, hence, suitable for the proximity-based, resource-constrained digital signature of documents.