Snowden: Anonymous 'Zcash' Could Solve Bitcoin Surveillance Risks


Snowden: Anonymous 'Zcash' Could Solve Bitcoin Surveillance Risks

The world’s most famous government whistleblower, Edward Snowden, last week referred to the anonymous cryptocurrency project Zcash as a solution to the surveillance risks of Bitcoin’s public transaction record.

Also read: The Encryption Cold War: Government VS Internet

The former National Security Agency contractor and now fugitive made the comments about Zcash during a video conference panel called “Decentralized and Encrypted,” part of an event called “Upgrade the Internet” hosted by VC firm BlueYard Capital in Berlin on June 1, 2016.

Zcash founder and CEO Zooko Wilcox also attended the event, and tweeted:

Zooko Wilcox Zcash Snowden tweet

The main conversation theme centered on how the Internet could be upgraded to remain “a space for permissionless innovation and freedom of expression.”

What is Zcash?

Zooko Wilcox Zcash
Zooko Wilcox

Zcash grew out of the Zerocoin project, which began as a cryptographic anonymity layer for Bitcoin before transforming into an independent cryptocurrency.

The current Zcash team features cryptographers and researchers from the Zerocoin project at Johns Hopkins University, including the renowned security expert Matthew D. Green.

Zcash founder Zooko Wilcox is a long-time computer security researcher, inspired by David Chaum’s writings about “privacy-preserving money.” Wilcox worked on Digicash, the digital currency Chaum created in the 1990s.

Transparency With privacy

In order to be transparent in its development and release, Zcash is currently available as a public alpha. On June 1, the project announced that it will begin a “mining slow start” in preparation for launch.

This method means mining rewards are slow at first and gradually increase over the first 5,000 blocks, ensuring a more equitable share of coins to all miners who join over that period.

Among the project’s financial backers is owner and liberty advocate Roger Ver.

Zcash has a public blockchain to show transactions, but hides the amount, sender and recipient addresses from all except those who hold the “view key.” The view key owner (i.e. the owner of the coins) can also allow others to see details associated with that key.

It does this by encrypting the transaction metadata rather than making it publicly available, as Bitcoin does. Full transaction outputs are not retained by Zcash nodes, which only record the ability to spend coins using proofs called “zk-SNARKs.”

Most transaction details can then be pruned from the blockchain.

Other projects seeking to avoid the “trackability” of public blockchains are altcoins Monero and Dash, and the anonymizing bitcoin wallet Samourai Wallet.

Possibility of Bitcoin ‘Greenlisting’

Bitcoin’s open blockchain and transaction record spanning its entire history has prompted frequent questions about privacy and coin fungibility. There have been several proposals over the years to ‘blacklist’ certain coins that can be traced back to crimes or thefts, or at least “greenlist” those considered to be “untainted” by their history.

Blockchain forensics is also a growing industry of interest to academics, regulators, tax offices and investigators. While Bitcoin users in future may be able to take further steps to protect their privacy, historic records are always available from a time before many users considered future implications.

Using publicly-available tools, researchers have been able to “de-anonymize” several bitcoin addresses, and make claims regarding certain notorious incidents in Bitcoin’s history.

It is yet to be seen if the public at large will flock to a new cryptocurrency promising anonymity. But Edward Snowden’s years of revelations about the sheer scope of our digital footprints, and governments’ appetites for total surveillance, has taken the topic beyond conspiracy theory and placed it front and center in the mainstream media.

Do you agree with Snowden that a public blockchain is a threat to privacy? Would you use an anonymous digital currency over bitcoin? 

Tags in this story
bitcoin privacy, dash, Edward Snowden, Monero, Zcash

Images courtesy of Wired, Zcash.

Jon Southurst

Jon Southurst has been interested in bitcoin since reading Neal Stephenson's 'Cryptonomicon' in 2012. A long-time tech writer, he has been a regular contributor at CoinDesk and has written for, DeepDotWeb and ancient print publications. He lives on an artificial island in Tokyo.

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