About me
*** I am on the job market looking for new position as cryptographer, cryptography researcher or security engineer. Please send me an e-mail if you want to chat about it! ***
I am a PhD student since 01.01.2020. at Cryptography and Network Security (CNS) group at TU Darmstadt, Germany. My advisor is Dr. Jean Paul Degabriele.
My main research areas are: tweakable ciphers, authenticated encryption, secure channels, analyzing secure network protocols.
I obtained a BSc in Computer Science at Faculty of Sciences, University of Novi Sad, Serbia. After that I got my MSc in IT Security at Ruhr-University Bochum, Germany.
I contribute to the development of libreswan, an IPsec/IKEv2 open-source client.
You can find me on Linkedin, GitHub and Google Scholar, or reach me at vukasin (at) vukasink.de
Publications
Rugged Pseudorandom Permutations with Beyond-Birthday-Bound Security [PDF]
Nilanjan Datta, Jean Paul Degabriele, Avijit Dutta, Vukašin Karadžić and Hrithik Nandi
ACM AsiaCCS 2026
Analyzing the WebRTC Ecosystem and Breaking Authentication in DTLS-SRTP [PDF]
Martin Bach, Vukašin Karadžić, Lukas Knittel, Robert Merget and Jean Paul Degabriele
35th USENIX Security Symposium 2026
Committing Authenticated Encryption: Generic Transforms with Hash Functions [PDF] [SLIDES] [VIDEO]
Shan Chen and Vukašin Karadžić
Advances in Cryptology - EUROCRYPT 2025
Populating the Zoo of Rugged Pseudorandom Permutations [PDF] [SLIDES] [VIDEO]
Jean Paul Degabriele and Vukašin Karadžić
Advances in Cryptology - ASIACRYPT 2023
Overloading the Nonce: Rugged PRPs, Nonce-Set AEAD, and Order-Resilient Channels [PDF]
Jean Paul Degabriele and Vukašin Karadžić
Advances in Cryptology - CRYPTO 2022
Note: In the field of cryptography, the authors are listed in the alphabetical order, and the concept of lead author does not apply. The only exception in the publications list above is the “Analyzing the WebRTC Ecosystem and Breaking Authentication in DTLS-SRTP” paper published at USENIX, which is a general IT security conference where the concept of lead author does apply.
Academic Service
External reviewer: ACNS '26, ACNS '25, ACNS '24, CCS '23, CRYPTO '23, CCS '22, CT-RSA '22, EUROCRYPT '22, CT-RSA '21, Financial Cryptography '21
Work Experience
01/2020 - 12/2025
TU Darmstadt, Germany.
Research associate at CNS group (Department of Computer Science).
03/2019 - 09/2019
achelos GmbH, Paderborn, Germany.
Student assistant (software engineer) working in IPsec/IKE(v2) team.
10/2018 - 02/2019
Ruhr-University Bochum, Germany.
Student assistant for supervision of exercises in "Programming in C" Bachelor course.
Major Open Source Contributions
November 2024
The Libreswan Project
Implemented mixing preshared keys during the IKE_INTERMEDIATE exchange in IKEv2 protocol (draft-ietf-ipsecme-ikev2-qr-alt-04). More details here.
September 2018
The Libreswan Project
Implemented redirect mechanism in IKEv2 protocol (RFC 5685), as part of Google Summer of Code 2018 program. More details here.
September 2017
The Libreswan Project
Implemented mixing preshared keys in IKEv2 protocol (RFC 8784). More details here.
Other Activities
December 2025
Co-authored the research that will be presented in the talk "DTLS-SRTP: The Protocol Everyone is Using But Nobody is Checking" at Real World Crypto 2026 (RWC'26) Symposium in Taipei, Taiwan.
September 2025
Participated at the invitation-only "Generic Attacks and Proofs in Symmetric Cryptography" workshop in Singapore.
September 2024
Research visit with Shan Chen at Southern University of Science and Technology (SUSTech), Shenzhen, China.
October 2023
Co-authored the research presented in the talk "Rugged Pseudorandom Permutations and Their Applications" at Third NIST Workshop on Block Cipher Modes of Operation in Rockville, MD, USA.
April 2022
Co-authored the research presented in the talk "Overloading the Nonce: Rugged PRPs, Nonce-Set AEAD, and Order-Resilient Channels" at Real World Crypto 2022 (RWC'22) Symposium in Amsterdam, Netherlands.
