Paper 2018/854

Universal Multi-Party Poisoning Attacks

Saeed Mahloujifar, Mahammad Mahmoody, and Ameer Mohammed


In this work, we demonstrate universal multi-party poisoning attacks that adapt and apply to any multi-party learning process with arbitrary interaction pattern between the parties. More generally, we introduce and study $(k,p)$-poisoning attacks in which an adversary controls $k\in[m]$ of the parties, and for each corrupted party $P_i$, the adversary submits some poisoned data $T'_i$ on behalf of $P_i$ that is still "$(1-p)$-close" to the correct data $T_i$ (e.g., $1-p$ fraction of $T'_i$ is still honestly generated). We prove that for any "bad" property $B$ of the final trained hypothesis $h$ (e.g., $h$ failing on a particular test example or having "large" risk) that has an arbitrarily small constant probability of happening without the attack, there always is a $(k,p)$-poisoning attack that increases the probability of $B$ from $\mu$ to by $\mu^{1-p \cdot k/m} = \mu + \Omega(p \cdot k/m)$. Our attack only uses clean labels, and it is online. More generally, we prove that for any bounded function $f(x_1,\dots,x_n) \in [0,1]$ defined over an $n$-step random process $x = (x_1,\dots,x_n)$, an adversary who can override each of the $n$ blocks with \emph{even dependent} probability $p$ can increase the expected output by at least $\Omega(p \cdot \mathrm{Var}[f(x)])$.

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Publication info
Published elsewhere. Minor revision. ICML 2019
BiasingCoin-TossingPoisoningMulti-party learning
Contact author(s)
mohammad @ virginia edu
2021-11-04: revised
2018-09-20: received
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Creative Commons Attribution


      author = {Saeed Mahloujifar and Mahammad Mahmoody and Ameer Mohammed},
      title = {Universal Multi-Party Poisoning Attacks},
      howpublished = {Cryptology ePrint Archive, Paper 2018/854},
      year = {2018},
      note = {\url{}},
      url = {}
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