Zcash Sapling - Reading Assignment

Read a Zcash blog post on Sapling, a recent protocol update. Answer the questions and post your answers below:

  1. According to the blog post, why are most Zcash transactions today transparent?
  2. Why does Sapling enable the use of hardware wallets?
  3. How do viewing keys change?
  1. Because using shielded transactions make the verification process longer and more complex, therefore users prefer to use transparent Bitcoin-like transactions.
  2. To be used in the transaction process as the spending key, so that users can construct the proof of knowledge through their computer and use the Hardware wallet to complete the transaction.
  3. Thanks to Sapling, viewing keys are able to make outgoing transactions visible for shielded addresses, showing information related to transaction values and making both memo fields and target addresses visible. Until this improvement only incoming transactions were accessible through viewing keys.
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1.Currently, most Zcash transaction use transparent addresses that function in the same way as Bitcoin. This is largely due to the computational cost of proving that shielded transactions are valid. With Sapling, we move one (giant) step closer toward the ubiquity of shielded addresses.

2.Today, the hardware that constructs the proof must also be in possession of the spending key that authorizes the transaction. Sapling changes this by allowing the hardware that constructs the proof to be independent from the hardware that signs for the transaction.

3.Viewing keys allow owners of shielded addresses the ability to view transaction details without exposing their private spending key. Additionally, these can be shared with trusted third parties for compliance, auditing or for other reasons. Currently, only incoming transactions are viewable.

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  1. According to the blog post, why are most Zcash transactions today transparent?

Zcash transaction use transparent addresses that function in the same way as Bitcoin. This is largely due to the computational cost of proving that shielded transactions are valid.

  1. Why does Sapling enable the use of hardware wallets?

All shielded transactions require the creation of a zero-knowledge proof. Today, the hardware that constructs the proof must also be in possession of the spending key that authorizes the transaction. Sapling changes this by allowing the hardware that constructs the proof to be independent from the hardware that signs for the transaction.

  1. How do viewing keys change?

Sapling extends the capability of the viewing key to include visibility into outgoing transactions for a shielded address. Visibility includes the transaction value, memo field and target address.

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  1. Due to the computational cost of proving that shielded transactions are valid.
  2. By allowing the hardware that constructs the proof to be independent from the hardware that signs for the transaction. Additionally, hardware wallets can support shielded addresses by allowing the connected computer to construct the proof without exposing the spending key to that machine.
  3. Viewing keys allow owners of shielded addresses the ability to view transaction details without exposing their private spending key. Additionally, these can be shared with trusted third parties for compliance, auditing or for other reasons. Currently, only incoming transactions are viewable.
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  1. According to the blog post, why are most Zcash transactions today transparent?
    the computational costs to create shielded transactions are too high

  2. Why does Sapling enable the use of hardware wallets?
    Sapling allows separation of construction of proof and signing of transactions. The hardware can remain in the hardware wallet while the computer which is connected to the internet constructs the proof without the need of the spending key.

  3. How do viewing keys change?
    with the viewing key, incoming transactions (value and memo field) of shielded transactions are viewable. After the update, also outgoing transactions (target address, value, memo) are viewable for shielded transactions,

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  1. According to the blog post, why are most Zcash transactions today transparent?
    Because of computational cost of working with shielded addresses.

  2. Why does Sapling enable the use of hardware wallets?
    Allowing the connected computer to construct the proof while the hardaware wallet does only need to add the spending key (without exposing) to complete the shielded transaction.

  3. How do viewing keys change?
    Now viewing key extends the visibility into outgoing transactions for a shielded addresses.

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1.This is largely due to the computational cost of proving that shielded transactions are valid.
2. Because it allows the connected computer to construct the proof without exposing the spending key to that machine.
3. It changes with the capability of the viewing key to include the visibility into outgoing transactions for a shielded address.

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  1. According to the blog post, why are most Zcash transactions today transparent?
    • Because the computational cost to prove that a shielded transaction is valid, most users don’t opt to use this anonymizing element, leaving transactions transparent.
  2. Why does Sapling enable the use of hardware wallets?
    • No longer does the hardware that constructs the zero-knowledge proof also be in possession of the spending key that authorizes the transaction because Sapling changes allows the hardware that constructs the proof to be independent from the hardware that signs for the transaction.
  3. How do viewing keys change?
    • Besides incoming transactions for a shielded address, with Sapling the viewing key can provide visibility into outgoing transactions too. Visibility includes the transaction value, memo field and target address.
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1- Due to the large computational cost of proving that shielded transactions are valid.

2- Hardware wallets can support shielded addresses by allowing the connected computer to construct the proof without exposing the spending key to that machine.

3-Sapling extends the capability of the viewing key to include visibility into outgoing transactions for a shielded address. Visibility includes the transaction value, memo field and target address.

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  1. Most Zcash transactions were transparent (‘transparent’ meaning the opposite here, ‘transparent’ in the sense of being completely ‘visible’ or ‘non private’, using only pseudonymous addresses like bitcoin does) because of low performance of the wallets or in other words because of the high requirements needed to build a/the shielded transaction proofs
  2. Sapling enables the use of hw-wallets because Sapling protocol change now allows the transaction data/proofs to be build in a non-trusted but powerful enough device to be fast and using the trusted device (where the privatekey is) eventually with little resources to be used just to sign that transaction before broadcasting it to the network.
  3. The old-viewing key would allow only to see the arriving amount value and the memo field, the sapling-viewing-key will allow to see incoming transactions value and the memo field, and additionally the outgoing transactions value, memo field and target address.
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  1. Mainly due to the computational cost of proving that shielded transactions are valid.

  2. Hardware wallets can support shielded addresses by allowing the connected computer to construct the proof without exposing the spending key to that machine.

  3. Sapling extends the capability of the viewing key to include visibility into outgoing transactions for a shielded address. Visibility includes the transaction value, memo field and target address.

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  1. because they use transparent adresses like btc
    2.with sapling the hardware that constructs the the zk proof can be different then the hardware that signs the transaction
    3viewing keys are able to make outgoing transactions visible for shielded addresses, showing information related to transaction values and making both memo fields and target addresses visible. Until this improvement only incoming transactions were accessible through viewing keys.
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According to the blog post, why are most Zcash transactions today transparent?

Because there is a large computational cost to validate shielded transactions. I would assume this means higher fees and would also imply that enabling shielded transactions by default would make the protocol too slow.

Why does Sapling enable the use of hardware wallets?

The update separates the signing of the transaction (which requires the private spending key) and the construction of the ZK proof. This means the spending key can be stored securely on the hardware wallet, do the signing, then delegate the computationally expensive proof to the connected computer.

How do viewing keys change?

They now allow the outgoing transactions of shielded addresses to be visible to a trusted 3rd party without exposing their private spending key- before only incoming transactions were visible.

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  1. Due to the computational cost of proving that shielded transactions are valid.

  2. Hardware wallets can support shielded addresses by allowing the connected computer to construct the proof without exposing the spending key to that machine.

  3. Sapling extends the capability of the viewing key to include visibility into outgoing transactions for a shielded address.

1 Like
  • According to the blog post, why are most Zcash transactions today transparent?
    Zcash transaction use transparent addresses that function in the same way as Bitcoin. This is largely due to the computational cost of proving that shielded transactions are valid.

  • Why does Sapling enable the use of hardware wallets?
    Allowing the connected computer to construct the proof while the hardaware wallet does only need to add the spending key (without exposing) to complete the shielded transaction.

  • How do viewing keys change?
    Now viewing key extends the visibility into outgoing transactions for a shielded addresses.

1 Like

1. According to the blog post, why are most Zcash transactions today transparent?
Most Zcash transactions today are transparent because of the computational cost of proving that shielded addresses are valid.

2. Why does Sapling enable the use of hardware wallets?
Sapling enables the use of hardware wallets because it creates stronger security. Users can construct the zkp from their computers while protecting their spending keys within their hardware wallets.

3. How do viewing keys change?
Viewing keys change with Sapling by allowing them to view outgoing shielded addresses including transaction value, memo field, and target address.

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  1. According to the blog post, why are most Zcash transactions today transparent?
    Due to the computational cost of proving that shielded transactions are valid.

  2. Why does Sapling enable the use of hardware wallets?
    Because it allows the hardware that constructs the proof to be independent from the hardware that signs for the transaction.

  3. How do viewing keys change?
    Viewing keys allow owners of shielded addresses the ability to view transaction details (transaction value, memo field and target address) without exposing their private spending key.

1 Like
  1. According to the blog post, why are most Zcash transactions today transparent?
  • Because the computational cost of proving that shielded transactions are valid.
  1. Why does Sapling enable the use of hardware wallets?
  • Because it allows the connected computer to construct the proof without exposing the spending key to that machine.
  1. How do viewing keys change?
  • Sapling extends the capability of the viewing key to include visibility into outgoing transactions for a shielded address. Visibility includes the transaction value, memo field and target address.
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Q1: For quicker TX processing times.

Q2: Sapling stops the hardware from doing both the construction and verification process and allows this to be done on separate hardware for security purposes.

Q3: Outgoing TXs are now visible for shielded addresses.

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