# Mimblewimble Non-Interactive Transactions **URL:** \ **Category:** Development and Technical Discussion\ **Created:** [February 8, 2018, 12:25am UTC](https://forum.grin.mw/t/mimblewimble-non-interactive-transactions/168 "2018-02-08T00:25:13Z")\ **Posts on this page:** 1\ **Showing post:** 7
**Author:** ![Elwailly](https://yyz2.discourse-cdn.com/flex036/user_avatar/forum.grin.mw/elwailly/32/85_2.png) [@Elwailly](https://forum.grin.mw/u/Elwailly)\ **Post date:** [February 15, 2018, 8:22am UTC](https://forum.grin.mw/t/mimblewimble-non-interactive-transactions/168/7 "2018-02-15T08:22:58Z")
A Non-Interactive Transaction is easily accomplished if Alice and Bob are ok with the following state of affairs: _Both Bob and Alice can spend the resulting transaction._ _No one else can spend it._ _When Bob comes online, he must immediately spend the transaction to a secure blinding factor of his own choosing and only then is the transfer between the two of them considered concluded._ This is accomplished by Alice directly generating a blinding factor for Bob that both Alice and Bob can use. x = Hash(m,aB) where B is Bob’s well known public key and m is unique to this transaction. Note x is now a shared secret between Alice and Bob since Bob can recover it using bA which is equal to aB. _This is used as Bob’s blinding factor_. Let X = xG Now Alice can directly sign the verification sum, xG + 0H, because she knows the new blinding factor, x. She can also participate in generating the range proof required by the transaction. The job of Bob’s wallet is a little more complicated unless we add a bit to the protocol to indicate this is a shared transaction. If A and m are selected as in the original post, then no interaction at all is required between Alice and Bob. Regards, Farid Footnote: Of course there is no way that Alice can prove to anyone else that Bob collected his grin. --- _[View the full topic](https://forum.grin.mw/t/mimblewimble-non-interactive-transactions/168)._