In some data communication configurations, data received from a sender may need to be viewed or otherwise processed by more than one entity with a corresponding client. For example, a message sent to a corporate email address may be viewed by either or both a mobile device and a desktop device. For the sender to utilize the strongest algorithm or protocol used by the recipient, it would therefore need to know which algorithms or protocols are supported by both the mobile and desktop mail clients. A system and method are provided to enable the mobile device to know about the capabilities of related mail clients associated with the communication address (e.g. email address) and vice versa such that the intersection of the capabilities (i.e. the strongest algorithm or protocol supported by all parties involved) can be chosen and the messages or data cryptographically processed accordingly.