Understanding Mimblewimble (MWEB on Litecoin), Part 2
This part deals with the changes in the protocol required to allow transactions to be formed without the cooperation of both the sender and the receiver. For the basics of how vanilla Mimblewimble operates, see Part 1.
The first insight would be that, given that the sender needs to communicate the gold & copper content of his coins to the receiver anyway in order that the new coins and kernel may be produced with the correct proportions, there needs to be a way of storing an encrypted message onto the blockchain containing this information, which only the receiver can decode. Later at some unspecified time, perhaps when the receiver wants to spend his coins, he may decrypt the message and thus learn the gold & copper content. Although he will probably already have an idea of the gold value, since he must have confirmed this when accepting the payment in the first place.
The receiver would publish his public key, perhaps as a component of his MWEB address, and then the sender may encrypt the information with it. The receiver thus decrypts the message with the corresponding private key.
