Reduced memory meet-in-the-middle attack against the NTRU private key

Christine van Vredendaal
2016 LMS Journal of Computation and Mathematics  
NTRU is a public-key cryptosystem introduced at ANTS-III. The two most used techniques in attacking the NTRU private key are meet-in-the-middle attacks and lattice-basis reduction attacks. Howgrave-Graham combined both techniques in 2007 and pointed out that the largest obstacle to attacks is the memory capacity that is required for the meet-in-the-middle phase. In the present paper an algorithm is presented that applies low-memory techniques to find 'golden' collisions to Odlyzko's
more » ... middle attack against the NTRU private key. Several aspects of NTRU secret keys and the algorithm are analysed. The running time of the algorithm with a maximum storage capacity of$w$is estimated and experimentally verified. Experiments indicate that decreasing the storage capacity$w$by a factor$1<c<\sqrt{w}$increases the running time by a factor$\sqrt{c}$.
doi:10.1112/s1461157016000206 fatcat:pmmtofcvd5gs7p4jt5w54ylgau