Efficient signature schemes supporting redaction, pseudonymization, and data deidentification

Abstract

In this paper we give a new signature algorithm that allows for controlled changes to the signed data. The change operations we study are removal of subdocuments (redaction), pseudonymization, and gradual deidentification of hierarchically structured data. These operations are applicable in a number of practically relevant application scenarios, including the release of previously classified government documents, privacy-aware management of audit-log data, and the release of tables of health records. When applied directly to redaction, our algorithm improves on [18] by reducing significantly the overhead of cryptographic information that has to be stored with the original data.

Generalizations and Extensions of Redactable Signatures with Applications to Electronic Healthcare

“…The authors of [18] have recently proposed a concept to apply redactable signatures in context of Personal Health Records (PHRs) to realize minimum disclosure of personal information and to achieve cryptographic enforcement of dependencies between parts containing personal information. Another recent work developed independently from ours by Haber et al [15] can be considered as closest to the ideas presented in this paper. They present redactable signatures that can be used for pseudonymization and de-identification of data, although they mainly focus on relational, i.e.…”

“…Furthermore, [15] have recently extended the approach of [2], such that a signer can specify which parts of a document are allowed to be redacted. Their approach is similar to the one of [1].…”

“…Hiding refers to the adversary's inability to reconstruct redacted parts of the document. Unforgeability is more involved and requires some definitions [2,15]:…”

“…Nevertheless, is should be noted that we require the standard signature scheme used to sign the root of the modified Merkle-tree to provide eUF-CMA security. Thereby, our game is based on the security model of [15]. Basically, an adversary who manages to win this game with non-negligible probability, will be able to breach the security of some of the used cryptographic primitives with non-negligible probability.…”

Security of Sanitizable Signatures Revisited

“…This is especially true since further properties have been added to the models in subsequent works, like the requirement that the sanitizer's identity remains hidden [5] in the sanitizable signature model of [3], resembling the above notion of transparency. Nonetheless, one can divide the literature about sanitizable signatures roughly into the works following the approach by Ateniese et al, e.g., [6,7], and the works based on the approach by Miyazaki et al, including [8,9,10,5,11].…”