Abstract Although very developed in many sectors (databases, filesystems), access control schemes are still somewhat elusive when it comes to wireless sensor net- works. However, it is clear that many WSN systems—such as healthcare and automotive ones—need a controlled access to data that sensor nodes produce, given its high sensitivity. Enforcing access control in wireless sensor networks is a particularly difficult task due to the limited computational capacity of wireless sensor nodes. In this paper we present a full-fledged access control scheme for wireless sensor data. We enforce access control through data encryption, thus embedding access control in sensor data units. We also propose a lightweight key generation mechanism, based on cryptographic hash functions, that allows for hierarchical key derivation. The suggested pro- tocol only relies on simple operations, does not require interactions between nodes and data consumers and has minimal storage requirements