blockchain personal data and the gdpr right to be forgotten

GDPR | Seers Article

How does GDPR affect the Blockchain and Cryptocurrency?

Blockchain and Cryptocurrency With GDPR are recognised data privacy regulation, organisations, both large and small, have been affected and will result in more significant impacts for individual businesses. The ethos behind Blockchain and crypto-currency are very much affected, how do you make these innovative architectures GDPR compliant?

Blockchain and Cryptocurrency

The fundamental logic behind the Blockchain is its security and encryption that makes data unreadable to others without the decrypt key, which will return the encrypted data to its original context. Transactions once written to the Blockchain are unchangeable, neither can be deleted, as this would corrupt the Blockchain.Data Subject Access Requests (DSAR) is one of the data subject rights conferred under the General Data Protection Regulation (GDPR).Data Subject Access Requests (DSAR) is one of the data subject rights conferred under the General Data Protection Regulation (GDPR).

With the Blockchain, an individual can review the complete audit trail of the cryptocurrency transactions for example; this gives complete transparency to all blockchain and cryptocurrency transactions that are written to the public Blockchain. Transparency on private Blockchains is different, as access becomes limited to those with access to the private key.

Blockchain and Persistent Storage

CreateRetrieveAppendBurn, is the methodology of storage on the Blockchain. Once a transaction is written to the Blockchain, it cannot be deleted or cancelled, the Blockchain can only be appended to, and existing data remains unaltered.

Therefore, in the manner that cryptocurrency such as Bitcoin or Etherium is transferred, the action cannot be changed once the transaction has been committed to the Blockchain. This does imply cryptocurrencies if stolen or illegally transferred, as it is not possible to undo these actions.

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The GDPR Implications

The regulations and rules of the GDPR are well documented with one of the fundamental values of the GDPR audit is the right to have your personal information erased. Another key element of the GDPR is the regulations behind how your data can leave the EU.  With websites, for example, this can be easier to manage, but with the Blockchain and cryptocurrency, this becomes more complex as there is no control over where the nodes of the Blockchain are hosted.  These nodes could be anywhere worldwide!

When the GDPR Regulations were formalized, Blockchain was in its infancy as it is likely this was not fully considered by the decision-makers.  The GDPR Regulations presumed it would always be possible for data privacy to be deleted. With the data written to the Blockchain, this is most certainly not the case.

Making the Blockchain and Cryptocurrency GDPR compliant

GDPR policy template effects on what can be stored on the Blockchain. In line with the GDPR Regulations, personal data should not be written to the Blockchain, as the data cannot be amended or erased once written. A possible solution for Blockchain and cryptocurrency transactions is that the personal data is not stored on the Blockchain, but personal data is stored externally to the Blockchain but linked by a reference generated on the Blockchain.

How this GDPR, Blockchain, Cryptocurrency workaround is described below in an example.

  1. A company has their software systems which store transactional data on the Blockchain.
  2. The company must ensure they are GDPR compliant. So personal information related to cryptocurrency transactions must be stored outside of the Blockchain but kept a high level of security.
  3. The software system sends a request for the personal data; the request is verified and checked to ensure it has the permission to view the data.  If the request is valid, a link is returned that will send the software a key to access the data that is stored offline.
  4. With the link to the personal data, the software can update the personal information or erase if requested, ensuring GDPR compliance.
  5. With regard to the blockchain and cryptocurrency transaction, the system can verify that the data has not been corrupted or tampered with by comparing the hash value of the retrieved data and the hash value provided by the Blockchain. If the two hash values match, this is the confirmation the data privacy is valid and has not been tampered with.

Are these workarounds beneficial?

These approached cannot be as efficient as writing and obtaining personal information directly from the Blockchain. These options are only considered in order to comply with the GDPR Regulations.

What are the benefits?

  •  These workarounds can ensure that the method is completely GDPR compliant.
  •  It becomes possible to remove data in line with the GDPR Regulations, creating the necessary flexibility in the Blockchain and for cryptocurrency transactions.

What are the downsides?

  • Transparency of data, a key to the Blockchain, is reduced. Once data is stored offline, it is no longer easy to identify who has access to the data.
  • The ownership of data stored on the Blockchain is no longer clear. Once data is stored outside of the Blockchain, the ownership of the data is no longer so clearly identified.
  • It is still necessary to have P2P integration.
  • For each new company added to the system, it is necessary to add a new P2P connection.
  • The Blockchain functions differently to its designed usage. The Blockchain becomes a lookup table to reference other data, instead of the infrastructure for storing transactions such as cryptocurrency.
  • With data spread across different entities, there are higher risks of security breaches or personal data being compromised, especially. When considering high-value transactions exists with cryptocurrency.
  • The process becomes more complicated.  The more complex processes become, increase the risk of errors and systems that are more risk to security issues.

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The GDPR Goal

The GDPR’s motive is to return the ownership of data to the individuals. One of the critical elements of the GDPR is the right to have your data erased. The Blockchain relies on the encryption keys, by no longer having access to the encryption keys, this makes the data inaccessible. But this is still not sufficient to be classed as data erasure, as the personal data. Would always be stored on the Blockchain.


With the Blockchain, technologies continuing to evolve and cryptocurrency become a feature of everyday life. GDPR gives us the opportunity to improve an individual’s ownership of their data. Try to maintain trust with third parties that may hold their data. To ensure GDPR compliance, there is no simple way to store p