Other existing solutions utilize either coin mixing or ring signatures. Coin mixing in many current implementations involve a lot of trust on the mixer and rely on finding other people to mix with which can take time. Ring signatures are a lot better in that it finds similar transactions of similar denominations to mix with but it means that there's still an element of traceability since the real transaction path is still somewhere in there and other outside data and topological analysis may narrow this down further.

https://github.com/zcoinofficial/zcoin/wiki/How-does-Zcoin-compare-to-other-anonymity-methods%3F

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