Abstract: Systems and methods are described for transferring and verifying the transfer of an asset from a limited-participant side chain back to a main blockchain. A public difference, associated with a secret difference, is determined as a difference between a main blockchain address and the public offline key of a transferring participant. The public difference is used, along with each participant public online key, to generate a ring signature key for each participant. A ring signature is then generated over the ring signature keys, based on the public online keys and a set of uniform random scalars (each associated with a participant public online key). The main blockchain address, a first coefficient from the ring signature, and the uniform random scalars are then published. When verified, the published ring signature shows that the transferring participant has control of the main blockchain address and the private offline key.