Linkability in zcash
Privacy and Linkability of Mining in Zcash
https://orbilu.uni.lu/bitstream/10993/39996/1/Zcash_Miner_Linking%20(2).pdf
https://www.youtube.com/watch?v=8bydpHmP-7k
On the linkability of Zcash transactions
https://arxiv.org/pdf/1712.01210.pdf
We then search for round-trip transactions, where the same, or nearly the same number of coins are sent from a transparent address, to a shielded address, and back again to a transparent address. We argue that such behavior exhibits high linkability, especially when they occur nearby temporally. Using this heuristic our analysis matched 31.5% of all coins sent to shielded addresses.