Conceptually, privacy can be defined as “the individual’s right to keep their data to themselves and not to have their data monitored by others’
Privacy is often at odds with two other important capabilities of blockchain applications: scalability and usability.
Privacy-scalability and usability as the axis of a triangle of conflicting forces.
Here are some of the privacy protocols and technologies worth following in the space:
CryptoNote is the protocol behind Monero, traceable ring signatures to obfuscate messages among a group of nodes in a decentralized network
zk-SNARKS: The protocol behind ZCash, zk-Snarks is a novel form of zero-knowledge cryptography that allows one party (the prover) to prove to another (the verifier) that a statement is true, without revealing any information beyond the validity of the statement itself.
zk-STARKS: Following our triangle thesis, one of the challenges of zk-Snarks is that is hard to be applied at scale as the complexity of the proofs scale linearly with the size of the database.
TEE: Trusted Execution Environments(TEE) have emerged as a popular way to offload confidential computations in blockchain technologies.
Enigma: Developed by cryptographers at MIT, Enigma is a blockchain protocol that enables the implementation of “secret contracts”. The protocol essentially allows nodes to compute using encrypted fragments of the smart contracts without having to decrypt them, which other blockchains cannot do
Oasis Labs: Ekiden Protocol relies on TEE environments to isolated private computations but leverage blockchain networks for scalability.