As I understand it, it means that a valid transaction is accompanied by a zero-knowledge proof, proving that this transaction is in fact valid, but revealing nothing about source or destination of funds.<p>Bitcoin requires each user to verify the entire blockchain, whereas the SNARK-technique means <i>a single</i> user can verify the blockchain, and produce a piece of data which essentially proves that 1. the verification has taken place and that 2. the claimed result of the verification (valid&#x2F;non-valid) is the actual result of running the verification.<p>If it sounds too good to be true, that&#x27;s because it <i>is</i> fairly revolutionary (if it works). Here&#x27;s the paper: <a href="https:&#x2F;&#x2F;eprint.iacr.org&#x2F;2013&#x2F;507.pdf" rel="nofollow">https:&#x2F;&#x2F;eprint.iacr.org&#x2F;2013&#x2F;507.pdf</a>