One embodiment provides a method for proxy
system mediated legacy transactions using multi-tenant transaction
database, including: utilizing at least one processor to execute computer code that performs the steps of: ascertaining, using a processor associated with a proxy
system, that a first transacting entity and a second transacting entity have placed a transaction on a multi-tenant transaction
database, the transaction including transfer of a legacy asset; decrypting, using a processor associated with the proxy
system, a
legacy system account access credential of the second transacting entity included in the transaction, the decrypting comprising
recovery of a function of a public key corresponding to a private key associated with the second transacting entity; confirming, using a processor associated with the proxy system, that the
legacy system account credential authorizes the second transacting entity to transfer the legacy asset; and transferring, using a processor associated with the proxy system, the legacy asset from the second transacting entity to the first transacting entity. Other aspects are described and claimed.