Encryption method for IPv6 networks provides new features and security concepts with a lot of profoundness likely Authentication Header and Encapsulating Security Payload Header (ESP). This paper shows the method of preventing certain types of network attacks over the internet and open issues of IPv6 security. It mainly deals with the Authentication and Encryption methods such as RSA and DES that are being used for years, and their drawbacks in IPv6 environment to enhance the multilevel security. There are three levels of encryption for security enhancement. The first level includes the conversion of a string of characters into corresponding ASCII values and then encrypt these ASCII values into random prime factors so that uniqueness is maintained. It has repeated patterns that is removed in the second level, where it uses two private keys which are prime for even and odd numbers and perform the addition with the first level results and convert into a binary form. In the third level, 2’s complement is applied on binary form and sent it through ESP packet of IPv6. On the other side, all the levels are repeated in reverse to get the original message. The experimental result shows the higher level of security for IPV6.