Zcash Sapling - Reading Assignment

Privacy Coins - Ultimate Course
#61

1.due to the computational cost of proving that shielded transactions are valid.
2.changes this by allowing the hardware that constructs the proof to be independent from the hardware that signs for the transaction.
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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#62

  1. Because it’s expensive to prove that shielded transactions are valid.

  2. I don’t understand this question. Why does Sapling do it? Well, I guess so that hardware wallets can use Zcash. Shouldn’t the question be “how”? If it were, then I would say that hardware wallets have a decoupled responsibility where one hardware wallet constructs a signature using the spending key, while another constructs the proof.

  3. Until now (time of article) shielded address were only able to see the incoming transactions. With Sapling these addresses will also be able to see the outgoing transactions without revealing their private spending key.

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#63

Transaction signing is a CPU intensive operation and hardware wallets like Ledger are not capable to sign the transaction on their own. Spliting the two made the use of hardware wallets possible because you can create proof without sending the key from your wallet to the computer that signs a transaction :slight_smile:

#64

Cool, thanks for reply. So if I were to send you some Zcash, I would provide the spending key along with the signature, and you would supply the proof. Correct?

#65

Basically you provide the signature and then the PC you have your HD wallet connected to constructs the proof :slight_smile:

#66

1. According to the blog post, why are most Zcash transactions today transparent?
This is due to do a shielded transaction is expensive.
2. Why does Sapling enable the use of hardware wallets?
Because it decouples the spending key from the computer.
3. How do viewing keys change?
Before the change, the value of the transaction and memo are viewable, after changing, except the value of tx, memo, the target address also viewable.

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#67

Sorry man, don’t wanna waist your time. I just wanna make sure I understand this right.

First of all, hardware wallets are device specific, right?

So the hardware wallet that I downloaded onto my pc contains the private spending key and uses the key to construct the signature. It then uses the computational power of my pc to construct the proof without revealing the spending key. Is that correct?

#68

No, a hardware wallet is a dedicated piece of hardware like Ledger or Trezor. They connect to the PC via USB and they have a very low power processor on board that signs the transaction on the device itself without revealing the private key to the PC.
In case of Zcash creating a proof for the transaction is computationally to expensive to be able to calculate on the hardware device, therefore it must be calculated on the PC instead. Before that it would only be possible if the hardware wallet would sent the key to the PC, but that would eliminate all the benefits of using a hardware wallet. :slight_smile:

#69

Coool, thanks man :slight_smile:

#70

  1. This is largely 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. 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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#71

  1. This is largely due to the computational cost of proving that shielded transactions are valid.

  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. 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.

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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#72

  1. According to the blog post, why are most Zcash transactions today transparent?
    because shielded tx cost more

  2. Why does Sapling enable the use of hardware wallets?
    because it allows the hardware which create the proof to be different from the one which sign the tx

  3. How do viewing keys change?
    they allow to check the tx details without showing the private key

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#73

  1. Most Zcash transactions were transparent prior to Sapling because of the computational cost of proving that shielded addresses are valid

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

  3. Prior to Sapling shielded addresses could support incoming viewing keys, where the value of all incoming transactions and the memo field are visible. With Sapling visibility extends to outgoing transactions including the transaction value, memo field and target address

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#74

1.) According to the blog post, why are most Zcash transactions today transparent?
This is largely due to the computational cost of proving that shielded transactions are valid.

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

3.) How do viewing keys change?
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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#75

1 This is largely due to the computational cost of proving that shielded transactions are valid.
2 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.
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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#76
  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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#77

  1. Most Zcash transactions today are transparent because of the computational costs of proving shielded transactions are valid.

  2. Sapling allows the hardware that constructs the proof to be independent from the hardware that signs for the transaction.

  3. Viewing keys can now let you see transactions of shielded addresses without using your private key. This can be shared with third parties for compliance.

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#78
  1. Currently, most Zcash transactions 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.
  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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#79
  1. According to the blog post, why are most Zcash transactions today transparent?
    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. Why does Sapling enable the use of hardware wallets?
    Payments involving the new Sapling z-addresses can be constructed in as little as a few seconds and with only 40 megabytes of memory. Exchanges, mobile wallet providers, vendors and other 3rd parties will now be able to support shielded addresses.
    The increased use of shielded addresses will improve the effective privacy for the entire network
  3. 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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#80

  1. According to the blog post, why are most Zcash transactions today transparent?
    Due to the computational cost to prove that a shielded transaction is valid, most users neglect this feature, leaving transactions to be transparent.

  2. Why does Sapling enable the use of hardware wallets?
    Because it allows the connected computer to construct the proof and be independent from the hardware that signs it. Basically, to separate the signer from the constructor of the proof.

  3. How do viewing keys change?
    Viewing keys allow the viewing of transaction details without exposing the private spending key.

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