# A Comment on Privacy-Preserving Scalar Product Protocols as proposed in "SPOC"

arXiv: https://arxiv.org/abs/1906.04862 · HTML: https://mlsanity.com/paper/1906.04862/

## Key facts

- Cited by 1 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 11 Jun 2019.

## Built on by (most cited first, 1 of 1)

- [Privacy preserving n-party scalar product protocol](https://mlsanity.com/paper/2112.09436/) (2021)

## Abstract (arXiv)

Privacy-preserving scalar product (PPSP) protocols are an important building block for secure computation tasks in various applications. Lu et al. (TPDS'13) introduced a PPSP protocol that does not rely on cryptographic assumptions and that is used in a wide range of publications to date. In this comment paper, we show that Lu et al.'s protocol is insecure and should not be used. We describe specific attacks against it and, using impossibility results of Impagliazzo and Rudich (STOC'89), show that it is inherently insecure and cannot be fixed without relying on at least some cryptographic assumptions.