MimbleWimble
Attacks
Ivan's Linkability attack against Grin
Ivan Bogatyy
The attack leverages one-kernel transaction (i.e., not merged with any other transactions, and thus the inputs of this transaction are linked to its outputs)
Possible in Grin, especially because there are not enough transactions now
Beam: Decoy (aka Dummy) UTXOs
At every step of the Dandelion Stem Phase, Beam nodes check whether the merged transactions (might be only one transaction) have at least 5 outputs.
If not, decoy outputs are added to the merged transactions, making sure that the number of outputs is at least 5.
Auditability
BEAM
Wallet audit
Extensions
Karl W¨ust, Kari Kostiainen (ETH Zurich), Vedran Capkun (HEC Paris), and Srdjan Capkun
FC'19
Commitment-based Mimblewimble transactions
Regulation scheme: Receiving limit w/ ZKP
Limit the total amount of money that any user can receive (spend) anonymously within an epoch.
To exceed the limit, a receiver must reveal his identity to the regulator by encrypting it with the regulator’s public key
Better performance in creating a transaction than Zcash (nrryuya.icon > Light client friendly also?) Creation of a typical transaction and associated proofs takes > 0.1 seconds
Verification of 1000 transactions per second is possible (4 validators with 25 quad-core servers each)
Applications
Tutorials