US Patent 7788484 Using hierarchical identity based cryptography for authenticating outbound mail

A hierarchical identity based cryptographic system (“HIBC”) is integrated with the domain name system (“DNS”). A private key is assigned to each of the top level domain name authorities responsible for assigning the top level domain names (e.g., .net, .com, etc.). The private key is generated according to an HIBC system, wherein the corresponding public key is based on the identity of the particular domain authority. When user requests a domain name from one of the top level domain name authorities, the user is issued a private key that is generated by the top level domain authority using its private key and the identity of the user according to the particular HIBC system implemented. The user's corresponding public key can be derived from the identity of the user and the public key of the top level domain name authority. Similarly, when the user adds servers and accounts to the users domain, the user can generate private keys for the servers and accounts using the users private key according to the particular HIBC system. Later, emails originating from the users domain can be authenticated by recipients using the public key associated with the top level domain name authority.