DKDMs are used for the exchange of encrypted DCPs between postproduction houses. Technically, there is not really a difference between a KDM and a DKDM. If the recitipient is a cinema, it's called a KDM, if it's another party involved in the postproduction, it's called a DKDM. Processing DKDMs needs the same operation and security requirements that are used in the creation and operation of KDMs for the digital cinema. 

easyDCP Creator+ enables to encrypt digital content and the standard accessory easyDCP KDM Generator generates KDMs and DKDMs for the transfer of digital cinema content to postproductions houses or cinemas. easyDCP KDM Generator+ can receive DKDMs in order to issue (D)KDMs from it.

How to generate KDMs and DKDMs in easyDCP: 

easyDCP KDM Generator(+): see manual section from section 4
easyDCP Creator+: see manual section 5.10