Patent ID: 7088821

Claim:
In a system for sending messages over a network between first and second computing units, method comprising the following steps: (a). computing r components of encrypting key e.sub.1, e.sub.2, . . . , e.sub.r and r components of decrypting key d.sub.1, d.sub.2, . . . , d.sub.r according to the following relations: (e.sub.1).(d.sub.1)+(e.sub.2).(d.sub.2)+ . . . +(e.sub.r).(d.sub.r)=(k.sub.1).(p−1).(q−1)+1and (d.sub.1)+(d.sub.2)+ . . . +(d.sub.r)=(k.sub.2).(p−1).(q−1), where: p and q are two prime numbers; k.sub.1 and k.sub.2 are suitable integers; and encrypting a message M into r cipher versions M.sub.1, M.sub.2, . . . , M.sub.r using the r blinded components of the encrypting key e.sub.1+t, e.sub.2+t, . . . ,e.sub.r+t as follows: M.sub.1=(M.sup.(e.sub.1+t))mod n M.sub.2=(M.sup.(e.sub.2+t))mod n . . . M.sub.r=(M.sup.(e.sub.r+t))mod n, where: n=p.q; t is a random number generated on an encrypting unit and discarded after encryption is complete; mod represents the remainder left when left hand operand is divided by right hand operand; (b). delivering all the cipher versions of the message individually to a destination unit in source routing mode, or hop-by-hop routing mode with a small time gap between every two consecutive cipher versions; (c). collecting all the cipher versions at the destination unit; (d). computing r number of values N.sub.1, N.sub.2, . . . , N.sub.r using r components d.sub.1, d.sub.2, . . . , d.sub.r of decrypting key, where: N.sub.1=((M.sub.1).sup.(d.sub.1))mod n N.sub.2=((M.sub.2).sup.(d.sub.2))mod n . . . N.sub.r=((M.sub.r).sup.(d.sub.r))mod n, where: n is the same composite number as used for encryption; (e). reproducing the original message M as follows: M=(N.sub.1).(N.sub.2) . . . (N.sub.r)mod n, where: n is the same composite number as used for encryption; wherein r=2.