The Ethereum Metropolis Testnet implements the zksnark technology, which makes it possible to verify zero-knowledge-proof transactions within the ethereum network.
Here is the first zkSnark transaction:
Here is the code:
zkSNARKs test code in solidity
https://gist.github.com/chriseth/f9be9d9391efc5beb9704255a8e2989d
This is one of the exciting parts about the upcoming ethereum hardfork !
