Christoph Striecks
@cstriecks.bsky.social
36 followers 24 following 1 posts
Senior Scientist in Cryptography at AIT Austrian Institute of Technology; alumni Karlsruhe Institute of Technology, more on https://christophstriecks.com
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Reposted by Christoph Striecks
kennyog.bsky.social
Grateful to @iacrcrypto.bsky.social for acting quickly to address serious concerns from the community.
Reposted by Christoph Striecks
drl3c7er.bsky.social
We have extended the submission deadline for the International Workshop on Foundations and Applications of Privacy-Enhancing Cryptography (PrivCrypt) by two weeks to April 4, 2025, AoE. Please help spread the word and consider submitting your work to join us in Munich in Summer 😎
drl3c7er.bsky.social
We are organising the International Workshop on Foundations and Applications of Privacy-Enhancing Cryptography (PrivCrypt) - co-located with ACNS 2025 end of June in beautiful Munich.

Submission deadline is March 21, 2025 (AoE).

Please help spread the word! 🙏

privcryptworkshop.github.io
PrivCrypt 2025
privcryptworkshop.github.io
Reposted by Christoph Striecks
drl3c7er.bsky.social
If you are looking for a PhD or PostDoc position in Cryptographic Engineering, please check the openings of Michael Hutter at our Research Institute CODE here in beautiful Munich. Please consider and help spread the word: iacr.org/jobs/item/3908
PhDs / PostDocs in Cryptographic Engineering
iacr.org
Reposted by Christoph Striecks
eprint.ing.bot
Malleable SNARKs and Their Applications (Suvradip Chakraborty, Dennis Hofheinz, Roman Langrehr, Jesper Buus Nielsen, Christoph Striecks, Daniele Venturi) ia.cr/2025/311
Abstract. Succinct non-interactive arguments of knowledge (SNARKs) are variants of non-interactive zero-knowledge proofs (NIZKs) in which complex statements can be proven in a compact way. SNARKs have had tremendous impact in several areas of cryptography, including verifiable computing, blockchains, and anonymous communication. A recurring concept in many applications is the concept of recursive SNARKs, in which a proof references a previous proof to show an evolved statement.

In this work, we investigate malleable SNARKs, a generalization of this concept of recursion. An adaptation of the existing concept of malleable NIZKs, malleable SNARKs allow to modify SNARK proofs to show related statements, but such that such mauled proofs are indistinguishable from “properly generated” fresh proofs of the related statement. We show how to instantiate malleable SNARKs for universal languages and relations, and give a number of applications: the first post-quantum RCCA-secure rerandomizable and updatable encryption schemes, a generic construction of reverse firewalls, and an unlinkable (i.e., computation-hiding) targeted malleable homomorphic encryption scheme.

Technically, our malleable SNARK construction relies on recursive proofs, but with a twist: in order to support the strong indistinguishability properties of mauled and fresh SNARK proofs, we need to allow an unbounded recursion depth. To still allow for a reasonable notion of extractability in this setting (and in particular to guarantee that extraction eventually finishes with a “proper” witness that does not refer to a previous SNARK proof), we rely on a new and generic computational primitive called adversarial one-way function (AOWF) that may be of independent interest. We give an AOWF candidate and prove it secure in the random oracle model.
Image showing part 2 of abstract.
cstriecks.bsky.social
Ludovic Perret (EPITA & SORBONNE) and I are organizing a workshop on "Quantum-Safe Hybrid Cryptography (QSHC)" under the umbrella of ACNS 2025.

Please consider submitting a contributed talk (2-page abstract) and helping us spread the word.

Link: sites.google.com/view/qshc25/...
QSHC 2025
About the Workshop This workshop aims to explore the synergies between (symmetric/asymmetric) quantum-safe and quantum cryptography. A leading example is the design of Hybrid Authenticated Key Exchang...
sites.google.com
Reposted by Christoph Striecks
drl3c7er.bsky.social
We are organising the International Workshop on Foundations and Applications of Privacy-Enhancing Cryptography (PrivCrypt) - co-located with ACNS 2025 end of June in beautiful Munich.

Submission deadline is March 21, 2025 (AoE).

Please help spread the word! 🙏

privcryptworkshop.github.io
PrivCrypt 2025
privcryptworkshop.github.io