Shielded Zcash transactions are completely private.
Like Bitcoin, Zcash transaction data is posted to a public blockchain; but unlike Bitcoin, Zcash ensures your personal and transaction data remain completely confidential. Zero-knowledge proofs allow transactions to be verified without revealing the sender, receiver or transaction amount. Selective disclosure features within Zcash allow a user to share some transaction details, for purposes of compliance or audit.
Zcash also allows for transparent transactions, to accommodate for wallets and exchanges that don’t support private transactions.