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Total Break of the SRP Encryption Scheme



Ray A. Perlner, Albrecht R. Petzoldt, Daniel C. Smith-Tone


Multivariate Public Key Cryptography (MPKC) is one of the main candidates for secure communication in a post-quantum era. Recently, Yasuda and Sakurai proposed in [7] a new multivariate encryption scheme called SRP, which combines the Square encryption scheme with the Rainbow signature scheme and the Plus modifier. In this paper we propose a practical key recovery attack against the SRP scheme, which is based on the min-Q-rank property of the system. Our attack is very efficient and allows us to break the parameter sets recommended in [7] within minutes. Our attack shows that combining a weak scheme with a secure one does not automatically increase the security of the weak scheme.
Proceedings Title
Selected Areas in Cryptography (SAC 2017)
Conference Dates
August 16-18, 2017
Conference Location


Multivariate Cryptography, SRP Encryption Scheme, Cryptanalysis, min-Q-Rank


Perlner, R. , Petzoldt, A. and Smith-Tone, D. (2017), Total Break of the SRP Encryption Scheme, Selected Areas in Cryptography (SAC 2017), Ottowa, -1, [online], (Accessed April 22, 2024)
Created December 23, 2017, Updated November 10, 2018