Paper 2018/858

Stronger Security for Sanitizable Signatures

Stephan Krenn, Kai Samelin, and Dieter Sommer


Sanitizable signature schemes (SSS) enable a designated party (called the sanitizer ) to alter admissible blocks of a signed message. This primitive can be used to remove or alter sensitive data from already signed messages without involvement of the original signer. Current state-of-the-art security definitions of SSSs only dene a \weak" form of security. Namely, the unforgeability, accountability and transparency definitions are not strong enough to be meaningful in certain use-cases. We identify some of these use-cases, close this gap by introducing stronger definitions, and show how to alter an existing construction to meet our desired security level. Moreover, we clarify a small yet important detail in the state-of-the-art privacy definition. Our work allows to deploy this primitive in more and different scenarios.

Note: Fixed a detail in the ENC IND-CPA definition

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Publication info
Published elsewhere. Minor revision. Data Privacy Management and Security Assurance 2015
digital signatures
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kaispapers @ gmail com
2018-11-03: revised
2018-09-22: received
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      author = {Stephan Krenn and Kai Samelin and Dieter Sommer},
      title = {Stronger Security for Sanitizable Signatures},
      howpublished = {Cryptology ePrint Archive, Paper 2018/858},
      year = {2018},
      doi = {10.1007/978-3-319-29883-2_7},
      note = {\url{}},
      url = {}
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