**Authors:** Nikolay A. Moldovyan

### Abstract

A new method is proposed to design short signature schemes based on difficulty of factorizing a composite number n=qr, where q and r are two large primes. Using the method new digital signature schemes (DSS) with the 320-bit and 240-bit signature size are developed. The characteristic feature of the 240-bit signature DSS is the use of "three-level" verification equation. The (k,g) signature corresponds to the H hash value and represents a pair of natural numbers having the size of 80 and 160~bits, respectively. The δ modulus is a prime number. The public key is the triple (α,β,p ) , where p=2n+1 is prime, β is the q order element modulo p,α is the γ order element modulo q. The private key is represented by the pair of two prime numbers (q, γ) .

Nikolay A. Moldovyan

Specialized Center of Program Systems "SPECTR",

Kantemirovskaya, 10, St.Petersburg 197342, Russia;

Phone/fax: 7-812-2453743,

E-mail:

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