Efficient unlinkable sanitizable signatures from signatures with re-randomizable keys

Authored book
(Volume of book series)

Publication Details

Author(s): Fleischhacker N, Krupp J, Malavolta G, Schneider J, Schröder D, Simkin M, Malavolta G
Publisher: Springer Verlag
Publication year: 2016
Title of series: Public-Key Cryptography - PKC 2016
Volume: 9614
Pages range: 301-330
ISBN: 9783662493830
Language: English


In a sanitizable signature scheme the signer allows a designated third party, called the sanitizer, to modify certain parts of the message and adapt the signature accordingly. Ateniese et al. (ESORICS 2005) introduced this primitive and proposed five security properties which were formalized by Brzuska et al. (PKC 2009). Subsequently, Brzuska et al. (PKC 2010) suggested an additional security notion, called unlinkability which says that one cannot link sanitized message-signature pairs of the same document. Moreover, the authors gave a generic construction based on group signatures that have a certain structure. However, the special structure required from the group signature scheme only allows for inefficient instantiations. Here, we present the first efficient instantiation of unlinkable sanitizable signatures. Our construction is based on a novel type of signature schemes with re-randomizable keys. Intuitively, this property allows to re-randomize both the signing and the verification key separately but consistently. This allows us to sign the message with a re-randomized key and to prove in zero-knowledge that the derived key originates from either the signer or the sanitizer. We instantiate this generic idea with Schnorr signatures and efficient Σ-protocols, which we convert into noninteractive zero-knowledge proofs via the Fiat-Shamir transformation. Our construction is at least one order of magnitude faster than instantiating the generic scheme of Brzuska et al. with the most efficient group signature schemes.

FAU Authors / FAU Editors

Malavolta, Giulio
Lehrstuhl für Informatik 13 (Angewandte Kryptographie)
Schröder, Dominique Prof. Dr.
Lehrstuhl für Informatik 13 (Angewandte Kryptographie)

How to cite

Fleischhacker, N., Krupp, J., Malavolta, G., Schneider, J., Schröder, D., Simkin, M., & Malavolta, G. (2016). Efficient unlinkable sanitizable signatures from signatures with re-randomizable keys. Springer Verlag.

Fleischhacker, Nils, et al. Efficient unlinkable sanitizable signatures from signatures with re-randomizable keys. Springer Verlag, 2016.


Last updated on 2018-13-11 at 13:50