Patent ID: 7529937

Claim:
A method for determining that a potential correspondent domain has compatible secure email technology in order to establish a link between a server of a source domain and a computer of a correspondent domain comprising: transmitting a discovery secret from the source domain to the correspondent domain wherein the discovery secret includes a data element specific to the correspondent domain and wherein the discovery secret includes a source domain address to which the correspondent domain sends a message in order to establish compatibility between the source domain and the correspondent domain; and receiving by the source domain via the source domain address an invitation from the correspondent domain wherein the invitation includes the data element or an element corresponding to the data element which may be used by the correspondent domain to initiate a process to establish compatibility with the correspondent domain; wherein the source domain verifies the data element received from the correspondent domain by re-computing and then comparing the data element receive for the correspondent domain with the data element included in the discovery secret transmitted to the correspondent domain; and wherein the source domain only corresponds with the correspodent domain when the data element provided by the correspondent domain is the same as data element included in the discovery secret so that a denial of service attack from a correspondent domain is mitigated.