紀要論文

情報漏洩耐性を有する暗号系に関する研究

A Study on Cryptosystems with Resilience against Information Leakage

jpn

24321192

https://doi.org/10.15002/00030609

法政大学大学院情報科学研究科

法政大学大学院紀要. 情報科学研究科編

19

1

6

2024-03-24

Version of Record

The contribution of the paper is twofold: (1) I show two attacks against a cheating detectable secret sharing scheme (CDSS for short) from NISS 2019. (2) I propose a certificate issuance system of public key infrastructure with intrusion-resilient signature and Intel SGX. Since the limited space available for writing, this abstract will focus on the first. The second contribution will be detailed in the full paper. A CDSS is a variant of secret sharing scheme with the extra functionality to detect forgery of shares when some of shares are submitted maliciously. In NISS 2019, Becerra and Vega proposed a CDSS which employs addition over Z_2m as the verification function whereas the secret is distributed and reconstructed with computation over F_2m. They proved that the scheme is secure and the bit length of the share meets the lower bound with equality. In this paper, I show that the scheme is insecure by showing that only a single cheater can forge the resulting secret without being detected by the reconstruction algorithm. I present two types of attack. The probability of successful cheating of the first attack is 1 but the pattern of forgery is limited. In the second attack, the successful cheating probability is less than the first one but the pattern of forgery is more flexible. The successful cheating probabilities of the proposed attacks are evaluated with the careful analysis about structures of additions over Z_2m and F_2m, which will be of independent interest.

Article

AA12746425