It is inter-alia disclosed a method performed by at least one apparatus, said method comprising receiving or causing of receiving a connection establishment message from at least one external apparatus or transmitting or causing of transmitting the connection establishment message to the at least one external apparatus; obtaining or causing of obtaining a decentralized identifier representative of the external apparatus based on the connection establishment message; obtaining or causing of obtaining at least one hash value generated based on at least part of the obtained decentralized identifier; storing or causing of storing the at least one hash value in association with at least part of the decentralized identifier in a securitized portion of a memory of a distributed ledger system comprising the peer-to-peer network based on a consensus processing involving at least a subgroup of the nodes of the peer-to-peer network.