An Improvement on Shimada's Public-Key Cryptosystem

Chin-Chen Chang; Sun-Min Tsu

doi:10.6180/jase.2000.3.2.01

An Improvement on Shimada's Public-Key Cryptosystem

Computer Science and Information Engineering

Chin-Chen Chang¹ and Sun-Min Tsu¹

¹Department of Computer Science and Information Engineering, National Chung Cheng University, Chaiyi, Taiwan, R. O. C

Received: January 1, 2000
Accepted: June 1, 2000
Publication Date: June 1, 2000

Download Citation: ||https://doi.org/10.6180/jase.2000.3.2.01

ABSTRACT

The difficulty of breaking Rabin's cryptosystem is the same as that of factoring its public key. So far, this has been proven to be very difficult. However the disadvantage of Rabin's cryptosystem is that the deciphering function cannot produce a unique plaintext. Many modified Rabin's cryptosystems have been proposed. Recently, an excellent scheme modified from Rabin's cryptosystem has been proposed by Shimada. Using Shimada's scheme, we can obtain the desired plaintext without any information additional to the ciphertext itself. Here we propose an improvement to this scheme to simplify the decryption process. Our effort makes the implementation of Shimada's public key cryptosystem more efficient.

Keywords: Rabin cryptosystem, ciphertext, plaintext, enciphering function, deciphering function

REFERENCES

[1] Denning, D. E. "Cryptography and Data Security," Addison-Wesley, Reading, Massachusetts, (1982).
[2] Rosen, K. H. "Elementary Number Theory and Its Applications," Addison-Wesley, Reading, Massachusetts, (1982).
[3] Rabin, M. O. "Digital Signatures and Public Key Functions as Intractable as Factorization," MIT/LCS/TR-212, January (1979).
[4] Shimada, M. "Another Practical Public-Key Cryptosystem," {\em Electronics Letters}, Vol. 28, No.23, pp. 2146-2147, Nov. (1992).