Patent ID: 8897442
Filing Date: 2014-11-25
Classification: H04L

Abstract:
1. An encryption device comprising: a random number generating unit that generates a random number r; a first encryption unit that generates a ciphertext C a function calculating unit that generates S a common key generating unit that generates a common key K, the common key being an element of a cyclic group G a second encryption unit that encrypts the random number r by common key encryption using the common key K to generate ciphertext C(Ψ+1); and a third encryption unit that generates a ciphertext C wherein Ψ is an integer greater than or equal to 1, φ is an integer greater than or equal to 0 and less than or equal to Ψ, n(φ) is an integer greater than or equal to 1, ζ(φ) is an integer greater than or equal to 0, λ is an integer greater than or equal to 1 and less than or equal to Ψ, I is a constant greater than or equal to 2 and less than or equal to n(0)+ζ(0), e