Efficient codes protect data from entangled quantum split tampering
Rate 1/5 Non-Malleable Codes against Entangled Split-State Tampering
Cryptography and Security
Summary
Data can sometimes be altered by attackers who mess with it in complicated ways, especially using quantum technology shared between two parts. This paper shows how to create special codes that prevent attackers holding entangled quantum states from changing classical messages, while still keeping the original message perfectly correct. The authors achieve this with a code that keeps a good balance between message size and protection, improving on previous work by handling all messages equally well, even in worst cases.
What this means in practice
- •For information security engineers: Develop data protection layers that resist advanced quantum tampering in split systems storing classical information.
- •For distributed system developers: Secure distributed storage components against local quantum attacks with entangled adversaries manipulating separate data halves.
Authors
Naresh Goud Boddu
Abstract
We construct efficient information-theoretic non-malleable codes for classical messages that are secure against two noncommunicating local quantum tampering operations with arbitrary pre-shared entanglement. For every sufficiently small fixed $ξ>0$ and all sufficiently large first-share lengths $n$, the codes have rate at least $1/5-ξ$, perfect correctness, and error $2^{-n^{Ω(1)}}$. Security holds for every message, with a single message-independent simulator for each attack. This resolves the constant-rate question for worst-case classical messages in the entangled two-split-state model. Our construction builds on the permutation-based two-split construction of Batra, Boddu, and Jain, which achieves rate approaching $1/5$ for uniformly random messages. We retain their architecture but replace the uniform message input to the permutation with a prescribed message concatenated with fresh uniform padding. Our main contribution is a worst-case security reduction for this modification.