To achieve legal interoperability, Block Labs solutions are designed and built according to the EU and GDPR guidelines with main GDPR compliance features; (1) transaction is authorized by the user; (2) blockchain network is used for transactions that include encrypted electronic data or document link, that only the receiver can open using his or her private key; (2) no personal information is located in the blockchain transaction; (3) send encrypted electronic data or documents are stored in the off-chain data repository (i.e. data repository of user choice and control) and can be erased on the user request; (4) the protocol records only links to encrypted files and hashes of the encrypted content on the blockchain, what safeguards the rights of individuals to confidentiality and privacy, and; (5) the sender and the receiver jointly assume responsibility for complying with the GDPR and establishing a lawful basis. 

The protocol does not store any personal data on the blockchain. The data is stored off-chain. The protocol records links to encrypted files and hashes of the encrypted content on the blockchain. The hashing of exchange data enables the GDPR compliance, for example, if there were a request to delete some data (i.e. documents), the network controller would be able to delete the requested data from off-chain storage, leaving what would then become an empty hash on-chain.

X.509 standard digital certificate can be used for data encryption, notarization of signed data, digital signature, digital identity verification and timestamp. With various European Union certificate publications, the X.509 standard is widely used and as such appropriate for blockchain digital identity integration. The X.509 Public Key Infrastructure is also approved by eIDAS (i.e. electronic IDentification, Authentication and Trust Services).

Embedded within the FOURid protocol, X.509 enables a self-sovereign framework of digital identity authorisation and ownership representation. All ID processes are fully automated and decentralized by their design, thereby enabling users to have full control and ownership over their identities and of any data that may be connected with them. Attached with a specific blockchain wallet address the X.509 digital certificate standard provides the off-chain identity connection for individuals and organizations.