Maintainer(s): SW van heerden
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Normal MimbleWimble does not have the concept of a multisig UTXO. The UTXO is a commitment
C(v,r) = r·G + v·H with
the value blinded. However, the blinding factor
r can be composed of multiple blinding factors where
r = r1 + r2 + ... + rn, as Pedersen commitments are linear.
The output commitment can then be constructed as
C(v,r) = r1·G + r2·G + ... + rn·G + v·H = (r1 + r2 + ... + rn)·G + v·H.
This can be exploited for multiple users where each participant has their own
ri and keeps their private blinding factor
hidden and only provides their public blinding factor.
The base layer is oblivious as to how the commitment and related signature were constructed.
To open such commitments (in order to spend it) only the n-of-n blinding factor
r is required, and not the original
aggregated signature that was used to sign the transaction. The parties that wants to open the commitment needs to
collaborate to produce the n-of-n blinding factor