1)What is a function that maps a domain into a range such that every function value has a unique inverse, with the condition that the calculation of the function is easy where as the calculation of the inverse is infeasible?
2)What is a function that is easy to calculate in one direction and infeasible to calculate in the other direction unless certain addi tional information is known?
3)In an RSA system, the public key of a given user is e = 31, n = 3599. What is the private key of this user?
Hing: First us trial and error to determine p and q; then use the extended Euclidean algorithm to find the multiplicative inverse of 31 modulo φ(n).