What is a characteristic of blockchain technology that raises GDPR concerns?

Immutability of stored data is a key characteristic of blockchain technology that raises concerns related to the General Data Protection Regulation (GDPR). This regulation emphasizes individuals' rights to control their personal data, including the right to access, rectify, and erase that data.

Blockchain's immutable nature means that once data is recorded on the blockchain, it cannot be easily altered or deleted. This poses a challenge for compliance with GDPR requirements, particularly the "right to be forgotten," which allows individuals to request the deletion of their personal information. The inability to modify or erase data once it's been added to a blockchain could conflict with these rights, making it an area of significant concern for organizations looking to leverage blockchain technology in compliance with GDPR regulations.

While interoperability, scalability, and flexibility in data formats are important aspects of blockchain, they do not directly pertain to the privacy concerns outlined in GDPR, particularly regarding the management and control of personal data.