Cryptography is a through-the-looking-glass twilight-zone cattywampus world - where zero knowledge is a good thing because it defines the most advanced level of cryptography - essentially impossible to hack.
Zk-SNARKs, the protocol used by Zcash is the most advanced zero-knowledge proof cryptography that exists. Zero-knowledge refers to the fact that one can cryptographically prove that they have some information without revealing anything about what that information actually is.
By risking his own freedom for the principle that everyone has a right to keep private their communication metadata (whom they talk to and when and for how long), Snowden has proven himself a stalwart privacy advocate - so it's not surprising that he is partial to the coins that max out on encryption and other privacy features.
There are of course issues and tradeoffs with any form of cryptography. Some of these are technical such as the time and memory required to generate a zcash transaction. Zk-snark technology also requires a convoluted setup phase, which could potentially be a point of vulnerability.
In the case of Zcash, there was an elaborate setup ceremony in which 6 individuals generated part of the final “master key”, which must then be destroyed. As long as at least one of those participants is honest and truly destroyed their portion, Zcash can be trusted.
Aside from hacking, another vulnerability, directly related to the complexity of zero-knowledge proofs, was raised by Peter Van Valkenburgh, Director of Research for Coincenter, at the Berlin conference as he interviewed Snowden.
Van Valkenburgh noted that the intricacies of both zero-knowledge cryptography and blockchain are so esoteric that the "venn diagram" intersection of people who are experts in both is vanishingly small, which can lead to a kind of brainpower centralization - a concentration of all the power over the network within very few brains.
Snowden cleverly shrugged off this concern with the quip that fortunately human intelligence will always have a normal distribution (or be decentralized, if you will) and new brains are continuously coming online.
Peter Van Valkenburgh, Director of research for Coincenter, while interviewing Snowden at BlockStack Berlin 2018, parses the more nuanced vulnerabilities of the intersection of high-level encryption and blockchain technology
Bitcoin's Major Flaw
According to Snowden, the debate about transaction speed is a non-sequitur because bitcoin's most glaring flaw is the transparency of its public ledger.
Satoshi defined a bitcoin as a chain of digital signatures. Each transaction gives the coin a new "owner" by simply appending the address of that owner onto the end of the chain. In this way the chain grows longer and longer as a thread weaving its way through the blockchain. The nature of a transparent, distributed, internally mathematically verifiable public ledger allows anyone to trace the entire transaction chain all the way back to the birth of each coin, kind of like a dollar bill with the initials of everyone who ever touched it written on it. So anyone can construct an entire network of transactions and thus economic relationships.
This concept is anathema to Snowden's privacy philosophy - with obvious analogies to the NSA's unlawfully constructed relationship network derived from cellphone metadata, that he exposed to the world.
Bitcoin's transparent public ledger is anathema to Snowden's vision of privacy of interactions, both communicative and transactional
Losing Their Chokehold
The question is not "do you have a right to do something if that right can, in any edge-case, possibly be abused?" ... I think there's a presumption there that we do not have a right to engage in private trade.
- Edward Snowden, former NSA contractor and whistleblower-in-exile
In an eloquent and profound response to the issue of private or "permissionless" trading - Snowden postulates the reason that governments are so fearful of losing their chokehold on currency regulation - money was the first database, so it has been regulated for a long, long time. He astutely observes that the fundamental building block of all monetary regulation is the presumption that private trade is not a right - and this presumption ought to be questioned.
Images via Shutterstock, Video clips via Youtube