CryptoDB
CASE: A New Frontier in Public-Key Authenticated Encryption
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| Presentation: | Slides |
| Conference: | TCC 2023 |
| Abstract: | We introduce a new cryptographic primitive, called Completely Anonymous Signed Encryption(CASE). CASE is a public-key authenticated encryption primitive, that offers anonymity for senders as well as receivers. A “case-packet” should appear, without a (decryption) key for opening it, to be a blackbox that reveals no information at all about its contents. To decase a case-packet fully – so that the message is retrieved and authenticated – a verification key is also required. Defining security for this primitive is subtle. We present a relatively simple Chosen Objects Attack (COA) security definition. Validating this definition, we show that it implies a comprehensive indistinguishability-preservation definition in the real-ideal paradigm. To obtain the latter definition, we extend the Cryptographic Agents framework to allow maliciously created objects. We also provide a novel and practical construction for COA-secure CASE under standard assumptions in public-key cryptography, and in the standard model. We believe CASE can be a staple in future cryptographic libraries, thanks to its robust security guarantees and efficient instantiations based on standard assumptions. |
BibTeX
@inproceedings{tcc-2023-33543,
title={CASE: A New Frontier in Public-Key Authenticated Encryption},
publisher={Springer-Verlag},
author={Shashank Agrawal and Shweta Agrawal and Manoj Prabhakaran and Rajeev Raghunath and Jayesh Singla},
year=2023
}