## A New Public-Key Cryptosystem over Quadratic Orders with Quadratic Decryption Time (2000)

Citations: | 7 - 2 self |

### BibTeX

@MISC{Paulus00anew,

author = {Sachar Paulus and Tsuyoshi Takagi},

title = {A New Public-Key Cryptosystem over Quadratic Orders with Quadratic Decryption Time},

year = {2000}

}

### Years of Citing Articles

### OpenURL

### Abstract

We present a new cryptosystem based on ideal arithmetic in quadratic orders. The method of our trapdoor is different from the Diffie-Hellman key distribution scheme or the RSA cryptosystem. The plaintext m is encrypted by mp r , where p is a fixed element and r is a random integer, so our proposed cryptosystem is a probabilistic encryption scheme and has the homomorphy property. The most prominent property of our cryptosystem is the cost of the decryption, which is of quadratic bit complexity in the length of the public key. Our implementation shows that it is comparably as fast as the encryption time of the RSA cryptosystem with e = 2 16 + 1. The security of our cryptosystem is closely related to factoring the discriminant of a quadratic order. When we choose appropriate sizes of the parameters, the currently known fast algorithms, for examples, the elliptic curve method, the number field sieve, the Hafner-McCurley algorithm, are not applicable. We also discuss that the chosen cip...