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Count Corruptions, Not Users: Improved Tightness for Signatures, Encryption and Authenticated Key Exchange
In the multi-user with corruptions (muc) setting there are n≥1 users, and the goal is to prove that, even in the face of an adversary …
Mihir Bellare, Doreen Riepel, Stefano Tessaro, Yizhao Zhang
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The Concrete Security of Two-Party Computation: Simple Definitions, and Tight Proofs for PSI and OPRFs
This paper initiates a concrete-security treatment of two-party secure computation. The first step is to propose, as target, a simple, …
Mihir Bellare, Rishabh Ranjan, Doreen Riepel, Ali Aldakheel
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Tightly-Secure Group Key Exchange with Perfect Forward Secrecy
In this work, we present a new paradigm for constructing Group Authenticated Key Exchange (GAKE). This result is the first tightly …
Emanuele Di Giandomenico, Doreen Riepel, Sven Schäge
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On the Tight Security of the Double Ratchet
The Signal Protocol is a two-party secure messaging protocol used in applications such as Signal, WhatsApp, Google Messages and …
Daniel Collins, Doreen Riepel, Si An Oliver Tran
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ISABELLA: Improving Structures of Attribute-Based Encryption Leveraging Linear Algebra
Attribute-based encryption (ABE) is a powerful primitive that has found applications in important real-world settings requiring access …
Doreen Riepel, Marloes Venema, Tanya Verma
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CCA Secure Updatable Encryption from Non-Mappable Group Actions
Ciphertext-independent updatable encryption (UE) allows to rotate encryption keys and update ciphertexts via a token without the need …
Jonas Meers, Doreen Riepel
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Key Exchange with Tight (Full) Forward Secrecy via Key Confirmation
Weak forward secrecy (wFS) of authenticated key exchange (AKE) protocols is a pas- sive variant of (full) forward secrecy (FS). A …
Jiaxin Pan, Doreen Riepel, Runzhi Zeng
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No more Reviewer #2: Subverting Automatic Paper-Reviewer Assignment using Adversarial Learning
The number of papers submitted to academic conferences is steadily rising in many scientific disciplines. To handle this growth, …
Thorsten Eisenhofer, Erwin Quiring, Jonas Möller, Doreen Riepel, Thorsten Holz, Konrad Rieck
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Generic Models for Group Actions
We define the Generic Group Action Model (GGAM), an adaptation of the Generic Group Model to the setting of group actions (such as …
Julien Duman, Dominik Hartmann, Eike Kiltz, Sabrina Kunzweiler, Jonas Lehmann, Doreen Riepel
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Multi-User CDH Problems and the Concrete Security of NAXOS and HMQV
We introduce CorrGapCDH, the Gap Computational Diffie-Hellman problem in the multi-user setting with Corruptions. In the random oracle …
Eike Kiltz, Jiaxin Pan, Doreen Riepel, Magnus Ringerud
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