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| Main Authors: | , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2506.17020 |
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| _version_ | 1866916802972352512 |
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| author | Ramanathan, Ravishankar Liu, Yuan Wu, Yutian |
| author_facet | Ramanathan, Ravishankar Liu, Yuan Wu, Yutian |
| contents | The question of security of practical device-independent protocols against no-signalling adversaries, the ultimate form of cryptographic security, has remained open. A key ingredient is to identify how the entropy in the raw outputs of a Bell test accumulates over $n$ sequential runs (termed time-ordered no-signalling) against a no-signalling adversary. Previous numerical and analytical investigations for small $n$ ($\leq 5$) had suggested that the min-entropy might not accumulate linearly in contrast to the case of quantum adversaries. Here we point out that despite the findings for small $n$, the min-entropy does in fact accumulate linearly for large $n$. We illustrate the difference in randomness accumulation against quantum and no-signalling adversaries with the paradigmatic example of the Chained Bell test for which we analytically derive the min-entropy. Finally, we illustrate the power of the no-signalling adversary by providing a class of attacks that allow an eavesdropper to perfectly guess the outputs of one player in general bipartite Pseudotelepathy games. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_17020 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Accumulation of Device-Independent Quantum Randomness against Time-Ordered No-Signalling Adversaries Ramanathan, Ravishankar Liu, Yuan Wu, Yutian Quantum Physics The question of security of practical device-independent protocols against no-signalling adversaries, the ultimate form of cryptographic security, has remained open. A key ingredient is to identify how the entropy in the raw outputs of a Bell test accumulates over $n$ sequential runs (termed time-ordered no-signalling) against a no-signalling adversary. Previous numerical and analytical investigations for small $n$ ($\leq 5$) had suggested that the min-entropy might not accumulate linearly in contrast to the case of quantum adversaries. Here we point out that despite the findings for small $n$, the min-entropy does in fact accumulate linearly for large $n$. We illustrate the difference in randomness accumulation against quantum and no-signalling adversaries with the paradigmatic example of the Chained Bell test for which we analytically derive the min-entropy. Finally, we illustrate the power of the no-signalling adversary by providing a class of attacks that allow an eavesdropper to perfectly guess the outputs of one player in general bipartite Pseudotelepathy games. |
| title | Accumulation of Device-Independent Quantum Randomness against Time-Ordered No-Signalling Adversaries |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2506.17020 |