8 Can the Blockchain Keep a Secret?

 

This chapter covers:

  • Identifying types of sensitive data encountered in DApps and how to safeguard it
  • Choosing the correct levels of transparency without compromising privacy
  • Standing up your first Hyperledger Fabric network
  • Using on-chain and off-chain techniques to protect privacy

“When it comes to privacy and accountability, people always demand the former for themselves and the latter for everyone else.”

― David Brin

“Spying among friends is never acceptable.”

― Angela Merkel

What is privacy? Without going into long, convoluted deliberations, we’ll simply assert that privacy is the ability to withhold information about oneself. When it comes to blockchains, there is an inherent tension between the desire to provide transparency and that of preserving privacy. The philosophical underpinnings of blockchains emphasize transparency -- the ability to monitor other nodes’ actions is core to DApps.

8.1           Blockchains and Privacy

8.1.1   Types of sensitive data

8.1.2   Mechanisms for Preserving Privacy

8.1.3   The Privacy and Transparency Spectrum

8.2           Increasing Transparency

8.2.1   Anchoring

8.2.2   Private Channels

8.3           Increasing Privacy

8.3.1   Zero-knowledge Proofs

8.3.2   Separate Blockchains using Hyperledger Fabric

8.4           Summary