P2 - Sanitizable Signatures

P2 – Sanitizable Cryptography


The project considers sanitization of authenticated encryptions. Such encryptions occur in secure channel protocols where the sender securely transmits data to a receiver via a service provider. The overall goal is to incorporate the possibility that a service provider can, if the sender or receiver supports this, modify the encrypted transmission in a controlled way, e.g., truncate the communication data at designated places if the receiver has a low bandwidth. The solutions will be smoothly integrable with the common channel protocols.


Patrick Harasser

Research Interests:

  • Provable security
  • Sanitizable signatures
  • Sanitizable channels
  • Sigma protocols

Sogol Mazaheri

Research Interests:

  • Provable security
  • Privacy and security of cryptographic protocols.
  • Cryptographic primitives and their relationships
  • Hardware-assisted cryptography


Ece, Olcay (2018):
Security of E-Mail-Encryption.
TU Darmstadt, [Bachelorarbeit]

Fischlin, Marc ; Harasser, Patrick (2018):
Invisible Sanitizable Signatures and Public-Key Encryption are Equivalent.
In: Applied Cryptography and Network Security - ACNS 2018, In: 16th International Conference, ACNS 2018, Leuven, Belgium, 2.7.-4.7. 2018, In: Springer International Publishing, LNCS 10892, [Online-Edition: https://www.springer.com/us/book/9783319933863],

Kiel, Robert (2018):
Zero-Knowledge Contingent Payments.
TU Darmstadt, [Masterarbeit]

Günther, Felix ; Mazaheri, Sogol (2017):
A Formal Treatment of Multi-key Channels.
In: CRYPTO 2017 - 37th International Cryptology Conference, Springer, Santa Barbara, CA, USA, [Konferenzveröffentlichung]

Erwig, Andreas ; Fischlin, Marc ; Hald, Martin ; Helm, Dominik ; Kiel, Robert ; Kübler, Florian ; Kümmerlin, Michael ; Laenge, Jakob ; Rohrbach, Felix (2017):
Redactable Graph Hashing, Revisited.
In: ACISP 2017, [Konferenzveröffentlichung]

Marson, Giorgia Azzurra ; Poettering, Bertram (2017):
Security Notions for Bidirectional Channels.
In: IACR Transactions on Symmetric Cryptology, S. 405-426, 2017, (Volume 2017 Issue 1), DOI: 10.13154/tosc.v2017.i1.405-426,

Fischlin, Marc ; Herzberg, Amir ; Noon, Hon Bin ; Shulman, Haya (2016):
Obfuscation Combiners.
In: International Cryptology Conference (CRYPTO), Santa Barbara, CA, USA, [Konferenzveröffentlichung]

Akleylek, Sedat ; Bindel, Nina ; Buchmann, Johannes ; Krämer, Juliane ; Marson, Giorgia Azzurra (2016):
An Efficient Lattice-Based Signature Scheme with Provably Secure Instantiation.
In: International Conference on Cryptology AFRICACRYPT 2016, Springer, Fes, Morocco, [Konferenzveröffentlichung]

Bernhard, David ; Fischlin, Marc ; Warinschi, Bogdan (2016):
On the Hardness of Proving CCA-Security of Signed ElGamal.
In: Public-Key Cryptography - PKC 2016, Springer, Taipei, Taiwan, In: LNCS, ISBN 978-3-662-49384-7,
DOI: 10.1007/978-3-662-49384-7_3,

Fischlin, Marc ; Günther, Felix ; Marson, Giorgia Azzurra ; Paterson, Kenneth G. (2015):
Data Is a Stream: Security of Stream-Based Channels.
In: Advances in Cryptology - CRYPTO 2015, Springer, Santa Barbara, CA, USA, [Konferenzveröffentlichung]

Fehr, Victoria ; Fischlin, Marc (2015):
Sanitizable Signcryption: Sanitization over Encrypted Data (Full Version).
In: IACR Cryptology ePrint Archive, S. 765, 2015, [Article]

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