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Reconstructing Trust Embeddings from Siamese Trust Scores (arxiv.org)
1 point by WASDAai on Aug 5, 2025 | hide | past | pdf | 1 comment on HN

In plain words: Pairing two agents' published trust scores and adding basic statistics lets a self-correcting loop rebuild the hidden trust vectors behind them. Even with added noise, the rebuilt vectors keep devices' relative distances right, showing that detailed scores leak private behavior.

Abstract · Reconstructing Trust Embeddings from Siamese Trust Scores: A Direct-Sum Approach with Fixed-Point Semantics

We study the inverse problem of reconstructing high-dimensional trust embeddings from the one-dimensional Siamese trust scores that many distributed-security frameworks expose. Starting from two independent agents that publish time-stamped similarity scores for the same set of devices, we formalise the estimation task, derive an explicit direct-sum estimator that concatenates paired score series with four moment features, and prove that the resulting reconstruction map admits a unique fixed point under a contraction argument rooted in Banach theory. A suite of synthetic benchmarks (20 devices x 10 time steps) confirms that, even in the presence of Gaussian noise, the recovered embeddings preserve inter-device geometry as measured by Euclidean and cosine metrics; we complement these experiments with non-asymptotic error bounds that link reconstruction accuracy to score-sequence length. Beyond methodology, the paper demonstrates a practical privacy risk: publishing granular trust scores can leak latent behavioural information about both devices and evaluation models. We therefore discuss counter-measures -- score quantisation, calibrated noise, obfuscated embedding spaces -- and situate them within wider debates on transparency versus confidentiality in networked AI systems. All datasets, reproduction scripts and extended proofs accompany the submission so that results can be verified without proprietary code.

Faruk Alpay, Taylan Alpay, Bugra Kilictas
arXiv:2508.01479 · cs.CR, cs.AI, cs.LG, cs.SI · submitted Aug 2, 2025
abstract · pdf · html · 22 pages, 3 figures, 1 table

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This paper dives into reversing the process of turning basic one-dimensional trust scores from security frameworks back into detailed high-dimensional embeddings that represent device trustworthiness, proposing a straightforward method that stitches together paired scores with statistical moments and proves it converges to a unique solution using fixed-point math. Through simulations with noisy data on 20 devices over 10 time steps, it shows the reconstructions keep the original geometric relationships intact, backed by error guarantees tied to data length, but warns that sharing these scores poses a real privacy threat by exposing underlying behaviors of devices and models. To counter this, it suggests fixes like rounding scores, injecting controlled noise, or scrambling embeddings, all while weighing the trade-offs between transparency and secrecy in connected AI setups.