How these principles apply to blockchain privacy claims

The most difficult blockchain privacy issue is the tension between immutable transaction records and an individual's rights over personal information.

For example, a company may record a customer's name, bank-account details, identity documents, transaction history, or health information directly on a blockchain. If the information later becomes inaccurate, is disclosed unlawfully, or is no longer needed, the distributed nature of the ledger may make deletion technically difficult.

Privacy claims may concern:

Unlawful collection or disclosure: Personal information is recorded without a valid legal basis.

Excessive data retention: Information remains accessible after the original purpose has ended.

Inaccurate records: Incorrect personal information continues to be replicated across network participants.

Re-identification: A supposedly anonymous wallet or transaction record can be linked to an identifiable person.

Data breaches: Private keys, identity information, or off-chain databases are compromised.

Unclear responsibility: Participants disagree about which organisation is responsible for the data processing.

Erasure and correction: The individual seeks deletion, correction, restriction, or removal of access to personal data.

A blockchain hash is not automatically anonymous. If it can reasonably be linked to an identifiable individual, or if the surrounding information allows identification, data-protection obligations may still be relevant.

Practical legal and technical safeguards

A privacy-conscious system should generally avoid placing directly identifying personal information on a permanent public ledger. A safer design may store personal information in a controlled off-chain database and put only a carefully assessed cryptographic reference on-chain. Even then, the reference must be evaluated for identifiability and linkability.

Other safeguards include data minimisation, restricted access, encryption, clear retention rules, privacy-impact assessments, and contractual allocation of responsibilities between the parties operating the network.

6. Important case laws

There are few reported judgments directly deciding civil liability for personal data stored on a blockchain. The following cases establish privacy, data-retention, erasure, and security principles that may apply by analogy. International decisions are persuasive comparisons, not binding Indian precedent.

1. Justice K.S. Puttaswamy (Retd.) v. Union of India, (2017) 10 SCC 1

Facts and issue: The Supreme Court considered whether privacy is protected as a fundamental right under the Constitution.

Decision: A nine-judge bench unanimously recognised privacy as a constitutionally protected fundamental right, including aspects of personal autonomy and informational privacy.

Legal principle: State action interfering with privacy must satisfy applicable constitutional requirements, including legality, legitimate purpose, and proportionality.

Relevance: If a government-backed blockchain records identity, health, financial, or land-related information, the system's design and use may raise constitutional privacy questions. The judgment also supplies an important framework for assessing privacy interests in the digital environment.

2. K.S. Puttaswamy v. Union of India (Aadhaar judgment), (2019) 1 SCC 1

Facts and issue: The Supreme Court considered the constitutionality of the Aadhaar framework, including the collection and use of biometric and identity information and the safeguards governing that data.

Decision: The Court upheld the Aadhaar Act's core framework subject to important limitations and struck down or invalidated certain provisions and uses.

Legal principle: Large-scale identity systems require safeguards governing collection, access, retention, security, and permissible use of personal information.

Relevance: A blockchain identity system may similarly create permanent, linkable records of an individual's activities. The judgment is relevant to the proportionality of data collection and the need to restrict the use of sensitive information, although it did not decide blockchain-specific questions.

3. District Registrar and Collector v. Canara Bank, (2005) 1 SCC 496

Facts and issue: The case concerned statutory powers to inspect private documents and the relationship between those powers and privacy.

Decision: The Supreme Court examined the constitutional implications of intrusive access to private documents and held that the relevant statutory provisions authorising broad inspection were unconstitutional in the circumstances considered.

Legal principle: Access to private information must have a lawful basis and cannot be justified merely by administrative convenience.

Relevance: A blockchain may make transaction histories accessible to numerous network participants. This case supports scrutiny of whether access to personal or confidential records is properly authorised. Its holding concerned document-inspection powers, not distributed ledgers.

4. Subhranshu Rout @ Gugul v. State of Odisha, 2020 SCC OnLine Ori 878

Facts and issue: The case involved alleged circulation and misuse of intimate images online and the difficulty of securing effective relief once material had been disseminated digitally.

Decision: The Orissa High Court discussed privacy, online abuse, and the importance of remedies addressing continuing dissemination of intimate material.

Legal principle: Digital dissemination can cause continuing privacy harm, and courts may need to consider remedies that address the persistence and accessibility of unlawful online content.

Relevance: This is useful by analogy where sensitive information is permanently recorded on a blockchain or repeatedly made available through associated applications. It illustrates the practical difficulty of removing information once widely distributed. It is not a judgment specifically about blockchain or a general ruling that every personal-data record must be erased.

5. Google Spain SL v. Agencia Española de Protección de Datos, Case C-131/12 (CJEU, 2014)

Facts and issue: Mario Costeja González sought removal of search results linking his name to an old newspaper notice about social-security debts that had been resolved.

Decision: The Court of Justice of the European Union held that a search engine could be required, in appropriate circumstances, to remove links from name-based search results where the information was inadequate, irrelevant, no longer relevant, or excessive in light of the processing purposes.

Legal principle: Data-protection rights may support de-referencing even where the original webpage remains online, subject to the relevant legal tests and balancing of rights.

Relevance: A blockchain record may be technically immutable, but access to it through search engines or applications may sometimes be restricted without changing the underlying ledger. This case illustrates one possible distinction between deleting data and reducing its discoverability. It applies EU law, not Indian law.

6. Data Protection Commissioner v. Facebook Ireland Ltd and Maximillian Schrems (“Schrems II”), Case C-311/18 (CJEU, 2020)

Facts and issue: The dispute concerned transfers of personal data from the European Union to the United States and whether the protections available there were adequate under EU data-protection law.

Decision: The CJEU invalidated the EU–US Privacy Shield framework and explained the safeguards and assessment required for certain international data transfers.

Legal principle: Organisations processing personal data across borders must consider whether the legal protections in the destination jurisdiction are adequate under the applicable regime.

Relevance: Public or permissioned blockchain networks may involve nodes, providers, and data recipients in several countries. Cross-border processing and access can therefore create compliance issues. This case does not establish a blockchain-specific rule and is relevant principally where EU data-protection law applies.

7. TU and RE v. Google LLC, Case C-460/20 (CJEU, 2022)

Facts and issue: Individuals requested the removal of search results and image thumbnails, alleging that the underlying information was inaccurate.

Decision: The Court addressed the evidentiary requirements for requests to remove links to allegedly inaccurate information, explaining how the data subject's rights and freedom of information must be balanced.

Legal principle: Requests to remove or de-reference information require a context-sensitive assessment, including the accuracy of the information and the competing interests involved.

Relevance: A blockchain-based application may continue to display inaccurate personal information even if the ledger itself cannot be edited. This case helps illustrate the potential role of correcting downstream displays, restricting access, or de-referencing content rather than assuming that a ledger entry alone resolves the legal question.

8. Budapest Főváros IV. Kerület Újpest Önkormányzat Polgármesteri Hivatala v. Nemzeti Adatvédelmi és Információszabadság Hatóság, Case C-46/23 (CJEU, 14 March 2024)

Facts and issue: The case concerned a data-protection authority's power to order the deletion of unlawfully processed personal data without waiting for an individual to submit a separate erasure request.

Decision: The CJEU held that a supervisory authority may, in exercising its corrective powers under the GDPR, order the controller or processor to erase unlawfully processed personal data even when the data subject has not made an erasure request.

Legal principle: Data-protection enforcement can include corrective deletion orders, and regulatory authorities may have powers that do not depend entirely on an individual's complaint.

Relevance: A blockchain operator subject to EU data-protection law may face regulatory difficulties if unlawful personal information is recorded in a way that cannot be removed. The case underlines the importance of designing systems to meet erasure obligations where they apply. It does not decide that every blockchain record must be deleted, regardless of other legal grounds or exceptions.

7. Civil remedies and enforcement

Depending on the jurisdiction, applicable statute, and facts, a person whose privacy has been infringed may seek:

Injunctions: Orders restraining unlawful disclosure or further processing.

Correction or deletion: Where a statute or legal cause of action permits it.

De-referencing or access restrictions: Measures limiting discovery of information through a website, search engine, or application.

Compensation: Where a recognised legal basis and the required proof of loss or actionable harm are established.

Regulatory complaints: Complaints to the competent data-protection authority, where one has jurisdiction.

Declarations: Findings about the lawfulness of processing or the parties' obligations.

Constitutional remedies: Where the challenged conduct is attributable to the State or otherwise engages constitutional jurisdiction.

The remedy must fit the problem. If information is permanently replicated across a blockchain, deleting the original entry may be technically impossible. But that does not necessarily remove other options, such as restricting access, deleting linked off-chain information, changing the application that displays the information, or seeking compensation where legally justified.

8. Key challenges in blockchain privacy litigation

Identifying the responsible party: A distributed network may include developers, validators, application operators, businesses, and users. Legal responsibility depends on their actual roles and applicable law, not simply on their participation in the network.

Proving personal-data status: A wallet address or hash may appear anonymous but could still be linkable to a person. Courts and regulators may need technical evidence to assess identifiability.

Reconciling erasure and immutability: Permanent storage can conflict with legal rights to erasure or correction. The conflict should be addressed during system design, not only after a claim arises.

Cross-border enforcement: Nodes and service providers may be located in several countries, making jurisdiction, governing law, and enforcement more complicated.

Establishing damages: A claimant may need to demonstrate unlawful processing and legally recognised harm, subject to the particular cause of action and statute.

9. Conclusion

Blockchain data privacy claims concern the intersection of informational privacy, data protection, civil liability, electronic records, and the technical persistence of distributed ledgers. Indian judgments such as Puttaswamy, the Aadhaar judgment, and District Registrar v. Canara Bank provide important privacy principles. International decisions such as Google Spain, Schrems II, and TU and RE v. Google illustrate how data-protection law can address discoverability, international transfers, and inaccurate information.

The main legal lesson is that immutability is a technical property, not a blanket legal defence to unlawful processing of personal data. Blockchain systems should be designed to minimise personal data on-chain, establish clear responsibility, and support lawful correction, restriction, or erasure where required.

This is a general educational overview focused on Indian law, with selected international cases for comparison. Many of the cited cases did not involve blockchain directly; they establish principles that may be relevant by analogy. The application of the Digital Personal Data Protection Act, 2023, depends on the provisions and rules in force for the relevant issue and date.