  Distributed ledger networks, chiefly those based on blockchain technologies,
currently are heralding a next generation of computer systems that aims to suit
modern users' demands. Over the recent years, several technologies for
blockchains, off-chaining strategies, as well as decentralised and respectively
self-sovereign identity systems have shot up so fast that standardisation of
the protocols is lagging behind, severely hampering the interoperability of
different approaches. Moreover, most of the currently available solutions for
distributed ledgers focus on either home users or enterprise use case
scenarios, failing to provide integrative solutions addressing the needs of
both.
  Herein we introduce the OpenDSU platform that allows to interoperate generic
blockchain technologies, organised - and possibly cascaded in a hierarchical
fashion - in domains. To achieve this flexibility, we seamlessly integrated a
set of well conceived OpenDSU components to orchestrate off-chain data with
granularly resolved and cryptographically secure access levels that are nested
with sovereign identities across the different domains.
  Employing our platform to PharmaLedger, an inter-European network for the
standardisation of data handling in the pharmaceutical industry and in
healthcare, we demonstrate that OpenDSU can cope with generic demands of
heterogeneous use cases in both, performance and handling substantially
different business policies. Importantly, whereas available solutions commonly
require a pre-defined and fixed set of components, no such vendor lock-in
restrictions on the blockchain technology or identity system exist in OpenDSU,
making systems built on it flexibly adaptable to new standards evolving in the
future.
