Yasufumi Hashimoto

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The unbalanced oil and vinegar signature scheme (UOV) is one of signature schemes whose public key is a set of multivariate quadratic forms. Recently, a new variant of UOV called Cubic UOV was proposed at Inscrypt 2015. It was claimed that the cubic UOV was more efficient than the original UOV and its security was enough. However, an equivalent secret key(More)
It is well known that the problem to solve a set of randomly chosen multivariate quadratic equations over a finite field is NP-hard. However, when the number of variables is much larger than the number of equations, it is not necessarily difficult to solve equations. In fact, when n ≥ m(m+1) (n,m are the numbers of variables and equations respectively) and(More)
Lifespan is regulated by a complex combination of environmental and genetic factors. Autophagy, which is a bulk degradation system of macromolecules and organelles, has an important role in various biological events. In Caenorhabditis elegans, several autophagy genes have been shown to have a role in promoting longevity, but many other autophagy genes have(More)
Multi-HFE (Chen et al., 2009) is one of cryptosystems whose public key is a set of multivariate quadratic forms over a finite field. Its quadratic forms are constructed by a set of multivariate quadratic forms over an extension field. Recently, Bettale et al. (2013) have studied the security of HFE and multi-HFE against the min-rank attack and found that(More)