Decentralized identity systems for brain data control

Introduction

Decentralized identity systems are digital identity frameworks that allow individuals to manage and control their identity information without depending entirely on a central authority. These systems commonly use technologies such as blockchain, distributed ledgers, cryptographic keys and verifiable credentials. In the context of neurotechnology, decentralized identity systems may provide individuals with greater control over brain data collected through brain-computer interfaces (BCIs), electroencephalography (EEG), functional magnetic resonance imaging (fMRI) and other neurological monitoring devices.

Brain data can reveal highly sensitive information about an individual's cognitive activities, emotional responses, neurological conditions and behavioural patterns. Its misuse may create serious privacy, discrimination and autonomy concerns. Decentralized identity systems are therefore being considered as a possible mechanism for managing consent, controlling access and recording the use of brain data. However, they also raise legal questions concerning data ownership, accountability, security and the right to withdraw consent.

Concept and functioning of decentralized identity systems

Decentralized identity systems allow individuals to establish and manage digital identities through cryptographic credentials. Instead of storing all identity information in one central database, the system distributes verification and control mechanisms across different participants.

Three important components are generally involved:

Decentralized identifiers (DIDs): Unique digital identifiers that allow individuals or organisations to establish verifiable identities.

Verifiable credentials: Digitally signed information confirming specific attributes, permissions or qualifications.

Distributed ledger technology: A shared record system that can help verify identity-related transactions and maintain tamper-evident records.

For brain data applications, an individual could use a digital identity wallet to grant a hospital, research institution or neurotechnology company permission to access particular neurological records. The permission could be restricted by purpose, duration and type of data.

However, storing raw brain data directly on a public blockchain would create significant privacy risks. A safer design generally keeps sensitive neurological information in secure off-chain storage while using cryptographic records to verify permissions and access events.

Legal framework governing brain data control

1. Right to privacy and informational autonomy

In India, Article 21 of the Constitution protects the right to life and personal liberty, including informational privacy. Brain data may reveal intimate information about an individual's mental and neurological characteristics. Consequently, collecting and processing such information should satisfy requirements of legality, legitimate purpose and proportionality.

The Digital Personal Data Protection Act, 2023, provides a framework for processing digital personal data in India. Its application depends on the statutory definitions, exemptions and commencement provisions. Where brain data identifies or relates to an identifiable individual, it may fall within its scope.

The Act addresses consent, specified legitimate uses, data fiduciary responsibilities, security safeguards and individual rights. A decentralized identity system cannot independently replace these legal obligations.

2. Data protection and consent management

Decentralized identity systems may support informed consent by allowing individuals to grant limited permissions to researchers and healthcare providers.

For example, a patient may authorise a hospital to access neurological information for treatment while refusing permission for unrelated commercial research.

Consent mechanisms should clearly explain:

The purpose of collecting brain data.

The categories of neurological information being processed.

The identity of organisations receiving access.

The duration and conditions of access.

The procedure for withdrawing consent.

The consequences of data sharing and further processing.

A blockchain record showing that consent was granted does not automatically establish that the consent was informed, freely given or legally valid.

3. Cybersecurity and accountability

Decentralized systems may reduce dependence on a single identity provider, but they introduce risks involving compromised private keys, unauthorised credential use, insecure smart contracts and permanent transaction records.

Organisations processing brain data must therefore adopt appropriate security measures. These may include encryption, access controls, authentication, independent security audits and incident-response procedures.

Major legal and regulatory challenges

1. Ownership and control of brain data

One major issue is whether individuals should have exclusive ownership or control over neurological information generated through medical devices or research systems. Healthcare institutions and technology companies may also have legitimate responsibilities and interests concerning records they collect or generate.

Legal frameworks should distinguish between the individual's privacy and access rights, the institution's responsibilities as a data processor or fiduciary, and any intellectual property rights in software or analytical methods.

2. Withdrawal of consent and immutability

Blockchain records are often designed to be difficult to alter. This creates tension with legal requirements concerning consent withdrawal, correction and erasure.

A practical solution is to avoid placing identifiable brain data or detailed personal information directly on an immutable ledger. Instead, the ledger may record permission references, cryptographic proofs and access events. Personal data can remain in controlled storage, where correction or deletion can be implemented when legally required.

3. Mental privacy and cognitive freedom

Brain data may reveal information that individuals have not consciously chosen to disclose. For example, neurological signals may be analysed to infer attention, emotional responses or certain health conditions.

Decentralized identity systems may strengthen individual control, but they cannot prevent every form of inference or misuse. Legal protection must therefore address not only access to raw brain data but also the creation and use of derived neurological information.

4. Cross-border data sharing

Neuroscience research frequently involves international institutions and cloud-based infrastructure. Decentralized identity systems may make credential verification easier across borders, but they do not eliminate applicable data-transfer restrictions.

Organisations must consider the laws governing the individuals concerned, the institutions involved and the locations where data is stored or processed.

Important case laws

1. Justice K.S. Puttaswamy v. Union of India (2017)

The Supreme Court of India recognised privacy as a fundamental right under the Constitution. The judgment identified informational privacy as an important dimension of personal liberty and dignity. Its principles are highly relevant to brain data because neurological information may disclose intimate aspects of an individual's identity and mental life.

2. District Registrar and Collector v. Canara Bank (2005)

The Supreme Court recognised privacy interests in personal financial documents and restricted unjustified state access to confidential information. Although the case did not concern neurotechnology, its reasoning supports safeguards against unnecessary access to sensitive personal records, including neurological information.

3. S. and Marper v. United Kingdom (2008)

The European Court of Human Rights held that the blanket and indefinite retention of DNA samples and profiles of individuals who had not been convicted violated Article 8 of the European Convention on Human Rights. The decision demonstrates that sensitive biological information requires proportionate collection and retention safeguards. Its reasoning is relevant by analogy to long-term storage of brain data.

4. Digital Rights Ireland Ltd v. Minister for Communications (2014)

The Court of Justice of the European Union invalidated the EU Data Retention Directive because its broad and indiscriminate retention requirements interfered disproportionately with privacy and data protection rights. The judgment is relevant to decentralized brain data systems because distributed storage and permanent access records should not result in excessive or unnecessary retention.

5. Schrems II (Data Protection Commissioner v. Facebook Ireland Ltd) (2020)

The Court of Justice of the European Union examined safeguards governing international transfers of personal data. It invalidated the EU-US Privacy Shield and emphasised the importance of effective protection when personal information is transferred internationally. The judgment is relevant to decentralized neurotechnology systems involving international research institutions and distributed infrastructure.

Safeguards and future regulatory development

A reliable decentralized identity framework for brain data should incorporate privacy by design and data protection by default. Individuals should be able to review permissions, identify recipients and withdraw access where legally possible.

Important safeguards include:

Keeping raw brain data outside public blockchains.

Using encryption and privacy-preserving verification.

Providing purpose-specific and time-limited access permissions.

Maintaining secure and reviewable access logs.

Establishing procedures for lost or compromised identity credentials.

Providing mechanisms for correction, deletion and consent withdrawal.

Conducting independent security and privacy assessments.

Conclusion

Decentralized identity systems offer a promising approach to strengthening individual control over brain data. They can improve consent management, identity verification and transparency in neurological research and healthcare. Nevertheless, decentralisation does not automatically guarantee privacy, security or legal compliance. The principles established in Puttaswamy, S. and Marper and Digital Rights Ireland demonstrate the importance of proportionality, confidentiality and meaningful individual control. Future regulation should ensure that technological innovation protects mental privacy, cognitive autonomy and the dignity of individuals while supporting responsible neurotechnology research.