This memo describes a mechanism to provide a secure binding between the multiple addresses with different prefixes available to a host within a multihomed site. The main idea is that information about the multiple prefixes is included within the addresses themselves. This is achieved by generating the interface identifiers of the addresses of a host as hashes of the available prefixes and a random number. Then, the multiple addresses are generated by appending the different prefixes to the generated interface identifiers. The result is a set of addresses, called Hash Based Addresses (HBAs), that are inherently bound.