Shielded Transactions¶
Zcash pioneered cryptographic transaction privacy using zero-knowledge proofs (zk-SNARKs). When you send or receive ZEC via a shielded address, the transaction is recorded on the blockchain — but the amount, sender, and recipient are all hidden.
How it works¶
A Zcash shielded transaction proves three things to the network using a zk-SNARK:
- The sender owns the funds being spent (without revealing which funds)
- No ZEC is created out of thin air (the output ≤ the input)
- The transaction is authorized by the spending key (without revealing the key)
The proof is verified by every full node, but the transaction data itself — amounts and addresses — is encrypted. Only the recipient (with the appropriate viewing key) can decrypt and read the details.
Orchard vs Sapling¶
ZecVault supports two shielded pools:
Orchard is Zcash's modern shielded pool, introduced in the NU5 upgrade. It uses the Halo 2 proving system — no trusted setup required, faster proof generation.
- Addresses start with
u1(Unified Address with Orchard receiver) - Best forward privacy
- Default pool for ZecVault receives and sends
- Some older wallets may not yet support sending to Orchard
Sapling was Zcash's first widely-adopted shielded pool. It provides equivalent on-chain privacy but uses an older proving system (Groth16) with a trusted setup.
- Addresses:
zs1...(Sapling-only) oru1...(Unified with Sapling receiver) - Supported by virtually all Zcash wallets and exchanges
- ZecVault can migrate Sapling funds to Orchard via Settings
When you share your Unified Address, the sender's wallet automatically picks the best pool it supports — Orchard first, then Sapling as a fallback.
What's private in a shielded transaction¶
| Information | Shielded (Orchard/Sapling) | Transparent |
|---|---|---|
| Sender address | Hidden | Public |
| Recipient address | Hidden | Public |
| Amount sent | Hidden | Public |
| Transaction memo | Encrypted (512 bytes) | Not available |
| Transaction existence | Public (timing/size visible) | Public |
| Block height | Public | Public |
Transparent transactions¶
Transparent addresses (t1...) offer no privacy — they work exactly like Bitcoin. Anyone can see:
- Which address sent funds
- Which address received funds
- The exact amount
ZecVault supports transparent addresses for compatibility with exchanges and legacy systems, but warns you prominently when sending to a transparent address and actively guides you toward shielded alternatives.
Shielding transparent funds
If you receive ZEC to a transparent address (common from centralized exchanges), ZecVault will offer to shield it into your Orchard pool. After shielding, the funds are indistinguishable from any other shielded balance.
The memo field¶
Every shielded transaction can carry up to 512 bytes of arbitrary text in an encrypted memo (ZIP-302). The memo:
- Is encrypted inside the shielded note
- Is readable only by the recipient (using their incoming viewing key)
- Is invisible to lightwalletd, blockchain explorers, and any third party
- Can contain UTF-8 text, base64 data, or structured data like ZV1 vault labels
ZecVault displays memos inline in the transaction history. They are decrypted locally during block scanning — never sent over the network in plaintext.