| Title | : | On Split-State Quantum Tamper Detection |
| Speaker | : | Naresh Goud Boddu (J.P. Morgan Singapore) |
| Details | : | Wed, 14 Jan, 2026 10:00 AM @ SSB 134 |
| Abstract: | : | Tamper-detection codes (TDCs) are fundamental objects at the intersection of cryptography and coding theory. A TDC encodes messages in such a manner that tampering with the codeword causes the decoder to either output the original message or reject it. In this work, we study quantum analogs of one of the most well-studied adversarial tampering models: the so-called t-split-state tampering model, where the codeword is divided into t shares and each share is tampered with locally. It is impossible to achieve tamper detection in the split-state model using classical codewords. Nevertheless, we demonstrate that the situation changes significantly if the message can be encoded into a multipartite quantum state entangled across the t shares. Concretely, we define a family of quantum TDCs on any t >= 3 shares, which can detect arbitrary split-state tampering so long as the adversaries are unentangled, or even limited to a finite amount of pre-shared entanglement. Previously, this was only known in the limit of asymptotically large t. As our flagship application, we show how to augment threshold secret sharing schemes with similar tamper-detecting guarantees. We complement our results by establishing connections between quantum TDCs and quantum encryption schemes. |
