Back to results
US 2002/0001383 A1Published application
Cryptosystem using multivariable polynomials
AssigneeMurata Machinery, Ltd.
InventorMasao Kasahara
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeMurata Machinery, Ltd.
InventorMasao Kasahara
Estimating the term…
Let us consider a message M an element (m1,m2, . . . ,mk) in a Galois field GF (2k), and multiply it by a product of polynomials β 1(α)-α t(α) into M(α). M(α)=Mβ1(α)·Mβ2(α) . . . Mβt(α) Combine a noise vector r(α) of n-k to M(α) in series so that the data is expanded into degree n. Next, they are transformed into Γ by permutation. Γ is multiplied by an element γx in the Galois field GF(2n) into cyphertext C(M), where γ is a primitive root of the multiplicative group of the Galois field GF(2n). Practically, when the message M is substituted for X in a public key C(X), the cyphertext C(M) is obtained. The cyphertext C(M) is multiplied by γ−x, is applied to an inverse permutation, and the noise vector r(α) is separated. Then, the inverse element of the product of β1(α)-βt(α) is multiplied and is raised to an adequate index. Then the decrypted message is obtained.
A decryption method with usage of a digital information processing device for decrypting cyphertext corresponding to plaintext and expressed by an element of a finite extension field of a prime field, wherein said element has a plurality of sub-elements, comprising:
A decryption method for decrypting cyphertext corresponding to plaintext and expressed by an element of a finite extension field of a prime field with usage of a digital information processing device, wherein said element has a plurality of sub-elements, comprising:
A decryptor for decrypting cyphertext corresponding to plaintext and expressed by an element of a finite extension field of a prime field, wherein said element has a plurality of sub-elements, comprising:
A recording medium, for decrypting cyphertext corresponding to plaintext and expressed by an element of a finite extension field of a prime field comprising a plurality of sub-elements, retrievable by a digital information processing device, and for making the digital information processing device perform:
A propagating signal, for decrypting cyphertext corresponding to plaintext and expressed by an element of a finite extension field of a prime field comprising a plurality of sub-elements, and storing codes retrievable by a digital information processing device and for making said digital information processing device perform:
Dependencies are inferred from the claim text.