it is a question of "information security"

In Secure Electronic Transaction, the purpose of Dual Signature is to link two messages that are intended for two different recipients. Discuss these two messages that are intended for two different recipients along with the need of linking. Also discuss if this purpose is fulfilled if we use KUC instead of KRc in the given model. Justify your answer with appropriate discussion. PI PIMD KRC DODO H 1111 POMD Dual Signature II H OI OIMD 0000