Every actor can create a root node and delegate a right to add a child node. Every node contains name of its’ creator or who added it, and value S. Sum of all values S at the same level of the tree must be equal to the sum of all values of the parent level nodes which in turn is equal to the sum of S’s of their parent nodes and so on up to the root.
Original question: Resending an encrypted message so that it’s guaranteed from being changed and is visible only to final receivers
I faced the next rather theoretical problem. Sender sends a message (I, Ch, S), where I is the proper content of the message, Ch is chain of receivers/resenders and S is just a sum. By having received the message Receiver sees all the information (I, Ch and S), next he/she can either accept or decline the message. By accepting it he is in right to resend the message as many times as he wants, adding every time its’ name to Ch, but S of all the resent messages is equal to the S of the original message.
Example. Alice sends <“1st message”, Alice, 500> to Bob, Bob resends <“1st message”, (Alice, Bob), 500> to Daenerys. Daenerys resends <“1st message”, (Alice, Bob, Daenerys), 300> to Jon and <“1st message”, (Alice, Bob, Daenerys), 200> to Tyrion.
The message must be encrypted , firstly, with Bob’s public key, then decrypted with his private key, then encrypted by Daenerys’ public key. But Dany can’t be sure that the content isn’t changed. Jon and Tyrion can’t be sure that the sum of the received messages is equal to the sum of the original message.