Definition: In some cases, two related messages need to be sent to the receiver, and the receiver can only open one message, while the other one only needs to be forwarded, and cannot be opened to view its contents.

(When the cardholder puts forward the ordering information to the merchant, he also gives the payment information to the bank, thus authorizing the bank to pay. However, cardholders do not want merchants to know the relevant information of their accounts, nor do they want banks to know the specific consumption content. He only needs to credit or debit the account according to the amount. )

Process: A person's double signature can send information to special merchants and banks, and special merchants can only unlock information related to themselves but not information to banks.

Illustration:/Shi Zhi/Shi Zhi -00 1.htm