• query
• authenticated
• spatial
• blockchain
• processing

In this thesis we will study the problem of authenticated query processing in the context of blockchain systems, with particular attention to the management of spatial data records.
With the increasing demand of distributed applications, the design of efficient techniques for storing and retrieving data from blockchains has become a crucial issue.
Moreover, blockchain networks constitute by definition an untrusted environment where lightweight nodes (e.g. mobile clients) with few computational resources must rely on more powerful service providers that fetch information on their behalf.
For these reasons, the retrieval process must be authenticated, so that peers can be sure about the integrity of the results.
In this regard, we will discuss state-of-the-art algorithms and mechanisms for building a verifiable query processing system, ranging from cryptographic primitives to indexing data structures.
We will then introduce some new methods that are specifically tailored for blockchains storing spatial records representing the location of physical objects in a geographical coordinate system.
These algorithms exploit the nature of the data to speed up the retrieval process, both inside a single block and along the entire blockchain.