1. A system for providing number privacy in a communication network, said system comprising at least one mobile switching center and at least two users with mobile phones, wherein said mobiles phones belong to the same service provider, further said system comprising: identifying a public key encryption algorithm and an associated pair of public and private keys by said service provider; encrypting the number of said first mobile phone, using the public key of the service provider, by said first mobile phone; sending name and said encrypted number to a second mobile phone through a connectivity means; storing said name and said encrypted number on said second mobile phone's phonebook; initiating a call from said second mobile phone to said first mobile phone using said name and transmitting said encrypted number to said network; and decrypting said encrypted number at a mobile switching center, using the private key of the service provider, for connecting to said first mobile phone,