Against the backdrop of token growth $ZEC (18x over the past year), in the ZCash network many blockchains have turned their attention to privacy.

Monero — ZCash’s main competitor — is too closed off, which is why it was removed from almost all exchanges. Other popular networks are practically fully public, and they have to build confidentiality on top of the existing architecture.

Solana and Privacy Cash

Solana supports several privacy models: on the blockchain they tested hiding the transfer amount, and they also have several protocols for ensuring privacy. I tested Privacy Cash, which allows you to hide the recipient, sender, and amount for transactions $SOL and USDC. It is also available on other networks. It works like a mixer: it mixes tokens and addresses in a pool (TVL >2 million), which makes it harder to trace cryptocurrency movements.

It’s interesting that Privacy Cash also works with native USDC. They have funds-in verification, but the risks of blocking are still high. For example, the Zama protocol ran into issues—Circle suspected one of the wallets in their private pool of violating the law and froze the entire pool. Later, the freeze was lifted at the request of the Zama team, but the aftertaste remained.

So Privacy Cash has risks, but they also earn well: about $3,000 per day. For a crypto protocol, that’s a lot (roughly the same amount of APT tokens are burned every day on Aptos due to gas usage).

Confidential Aptos

Aptos launched directly on-chain the ability to use confidential $APT . You create a private account inside the wallet (for example, privacy is supported by Petra both in the browser and in the mobile app), fund it with APT tokens, and then transfer cAPT to any address on the blockchain. Important: the link between wallets in this case is public, and the amount is encrypted.

The main use case is salary and other contract payments. The recipient and sender are not encrypted.

I studied this protocol and made the first public demo of APT confidentiality on mainnet. Technically, the blockchain allows making any assets confidential, but the Aptos Labs team does not include this feature. I had a conversation about this with Aptos cryptography lead Alin Tomescu—he said other assets aren’t included yet due to potential legal issues.

To make the feature truly useful, it’s enough to enable USDC, but it’s specifically in interaction with Circle that the biggest risks are.

Fully private Starknet

Starknet launched the STRK20 protocol in June. It allows you to hide the sender, recipient, and amount (if used correctly, but that’s a separate topic). Each operation costs 6 STRK (about 15 cents), and it works quite fast. Soon, support for private DeFi will be added. Right now there are already initial implementations of private swaps and token staking (with caveats, but that’s already quite good).

I’ll also note that USDC and strkBTC are supported—basically the main assets in DeFi, which cover most use cases. For USDC to work, they had to make a trade-off: at the request of regulators, auditors from Starknet can disclose certain transactions. That means transfers can be private to the public, but they are not absolutely closed to its creators.

In any case, it looks promising. I’m taking part in Starknet’s Private Sprint hackathon, and tomorrow I plan to do a small giveaway of private USDC on my X (ssadkov).

Have you used private protocols? Or is the wallet’s basic anonymity enough?