Jiun-Ming Chen

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“Algebraic Cryptanalysis” against a cryptosystem often comprises finding enough relations that are generally or probabilistically valid, then solving the resultant system. The security of many schemes (most important being AES) thus depends on the difficulty of solving multivariate polynomial equations. Generically, this is NP-hard. The related methods of(More)
Multivariate public-key cryptosystems (sometimes polynomial-based PKC’s or just multivariates) handle polynomials of many variables over relatively small fields instead of elements of a large ring or group. The “tame-like” or “sparse” class of multivariates are distinguished by the relatively few terms that they have per central equation. We explain how(More)
We herein discuss two modes of attack on multivariate public-key cryptosystems. A 2000 Goubin-Courtois article applied these techniques against a special class of multivariate PKC’s called “Triangular-Plus-Minus” (TPM), and may explain in part the present dearth of research on “true” multivariates – multivariate PKC’s in which the middle map is not really(More)
The XL (eXtended Linearization) equation-solving algorithm belongs to the same extended family as the advanced Gröbner Bases methods F4/F5. XL and its relatives may be used as direct attacks against multivariate Public-Key Cryptosystems and as final stages for many “algebraic cryptanalysis” used today. We analyze the applicability and performance of XL and(More)
Glutathione S-transferase M1 (GSTM1), one member of the GST family, is responsible for metabolism of xenobiotics and carcinogens. Myeloperoxidase (MPO) plays an important role in the oxidation and activation of carcinogens and nitric oxide. Allelic variants of GSTM1 and MPO gene polymorphisms might impair detoxification function and increase the(More)
Multivariate (or MQ) public-key cryptosystems (PKC) are alternatives to traditional PKCs based on large algebraic structures (e.g., RSA and ECC); they usually execute much faster than traditional PKCs on the same hardware. However, one major challenge in implementing multivariates in embedded systems is that the key size can be prohibitively large for(More)
In 2002 the authors introduced the new genre of digital signature scheme TTS (Tame Transformation Signatures) along with a sample scheme TTS/2. TTS is from the family of multivariate cryptographic schemes to which the NESSIE primitive SFLASH also belongs. It is a realization of T. Moh’s theory ([31]) for digital signatures, based on Tame Transformations or(More)