Suppose a message is encoded and then passes through the hands of an adversary who can manipulate it before the receiver decodes. A tamper detection code guarantees that the decoder detects this adversary, except with a tiny probability. Since Jafargholi and Wichs (TCC 2015), such codes are known to exist against enormous families of tampering functions, as long as the family avoids the identity and constant maps. Quantum analogs, due to Boddu-Kapshikar (Quantum 2023) and Bergamaschi (Eurocrypt 2024), have so far been restricted to unitary tampering.

This talk covers two recent works that move past that restriction. The first handles arbitrary quantum maps upto some natural conditions. We will also look at separation from the classical world and introduce a relaxation of tamper detection that is impossible classically but can be achieved with quantum encodings.

In the second part, we will add secrecy to the mix. We will look at a keyless primitive where along with tamper detection, we want that adversary does not learn anything about the message.

Based on joint work with Anne Broadbent and Denis Rochette.

1. Towards Universal Quantum Tamper Detection (IEEE Transactions on Information theory and QCRYPT 2026)

2. Keyless secrecy against bounded adversaries (https://arxiv.org/abs/2609.12251 [2])