Patent ID: 6721421
Filing Date: 2004-04-13
Classification: H04L

Abstract:
A method for decrypting a first message (â€œcâ€ ) from a second message (â€œmâ€ ), comprising the steps of:determining a public key which includes a permutation polynomial P(x) and a product (â€œnâ€ ) of a first large prime number (â€œpâ€ ) and a second large prime number (â€œqâ€ ); forming a secret key which is composed of the first and second large prime numbers; encrypting the first message using the public key, the secret key and the following equation: c=P(m) mod n, wherein P(m)=P(x); and calculating an unambiguous zero point of the permutation polynomial using the following equation: P(x)âˆ’c mod n, wherein the unambiguous zero point is calculated for the first large prime number and the second large prime number to decrypt the first message (â€œcâ€ ) using the following equations:p(x)=P(x)âˆ’c mod p, and q(x)=P(x)âˆ’c mod q, wherein the second message (â€œmâ€ ) is formed using the following equation:m=bÂ·uÂ·p+aÂ·vÂ·q mod n, and wherein uÂ·p+vÂ·q=1, anda and b are values which are calculated using the following equations: ggT(p(x),xpâˆ’x) mod p=xâˆ’a, and ggT(q(x),xqâˆ’x) mod q=xâˆ’b.