<p>In ZeroCash they perform transactions <a href="https://youtu.be/Rm-p8rrR9c8?t=1486" rel="nofollow noreferrer">like this</a>. I want to unravel and understand how z-addresses work in ZCash. It shall be described simply in <a href="https://electriccoin.co/blog/zcash-private-transactions/" rel="nofollow noreferrer">here</a> and <a href="https://github.com/zcash/zips/blob/master/protocol/protocol.pdf" rel="nofollow noreferrer">in-depth, revised here</a> and <a href="https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&amp;arnumber=6956581" rel="nofollow noreferrer">here (older, a bit simpler)</a>. Simply put it shall be described here:</p>

<p><a href="https://i.sstatic.net/VpFB5.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/VpFB5.png" alt="Zerocash: Decentralized Anonymous Payments from Bitcoin, page 11/469"></a></p>

<p>or even simpler here:</p>

<p><img src="https://i.sstatic.net/PIFEG.jpg" width="300">
<img src="https://i.sstatic.net/YPX3W.jpg" width="300">
<img src="https://i.sstatic.net/zBKK5.jpg" width="300">
<img src="https://i.sstatic.net/N85OY.jpg" width="300"></p>

<p>Blue is what gets into the ledger including stuff like <code>cm</code>, <code>a_{pk}</code>, <code>hash(sn)</code>.</p>

<p>In simple terms here is how I understand the algorithm and please correct me if I am wrong: A payer (slide #5) passes a value onto the chain as if it is passed by the payee. And this where I stop getting it:</p>

<ol>
<li><strong>How payer proves that he</strong> indeed <strong>can spend that value</strong> if he makes it look like operation is done from payee's perspective?</li>
<li>If <code>value</code>, <code>rho</code>, <code>r'</code> and <code>r''</code> are passed in the form of payee's public key how does it not make such transaction capable to happen only once\or how is it checked and proved?</li>
<li>If a transaction can happen only one and payer needs to prove that he has funds for it how he can not be linked to that transaction?</li>
</ol>

CC BY-SA 4.0
2020-03-24T07:29:58.253Z
Dear moderators, please do care to explains why the hall on bloody earth question on the fundamentals of one of the top five blockchain systems (zcash) is offtopic on a website about blockchain?!?
Blender
CC BY-SA 4.0
2020-03-24T08:45:02.250Z
See: https://bitcoin.stackexchange.com/help/on-topic
chytrik
<zcash><zero-knowledge>
How private shilded transactions to payee address works in ZeroCash from the information point of view?
Blender
# How private shilded transactions to payee address works in ZeroCash from the information point of view?

(Asked by: username_0 on 2020-03-23)

In ZeroCash they perform transactions [like this](https://youtu.be/Rm-p8rrR9c8?t=1486). I want to unravel and understand how z-addresses work in ZCash. It shall be described simply in [here](https://electriccoin.co/blog/zcash-private-transactions/) and [in-depth, revised here](https://github.com/zcash/zips/blob/master/protocol/protocol.pdf) and [here (older, a bit simpler)](https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6956581). Simply put it shall be described here:

[![Zerocash: Decentralized Anonymous Payments from Bitcoin, page 11/469](https://i.sstatic.net/VpFB5.png)](https://i.sstatic.net/VpFB5.png)

or even simpler here:

![](https://i.sstatic.net/PIFEG.jpg)
![](https://i.sstatic.net/YPX3W.jpg)
![](https://i.sstatic.net/zBKK5.jpg)
![](https://i.sstatic.net/N85OY.jpg)

Blue is what gets into the ledger including stuff like `cm`, `a_{pk}`, `hash(sn)`.

In simple terms here is how I understand the algorithm and please correct me if I am wrong: A payer (slide #5) passes a value onto the chain as if it is passed by the payee. And this where I stop getting it:

1. **How payer proves that he** indeed **can spend that value** if he makes it look like operation is done from payee's perspective?
2. If `value`, `rho`, `r'` and `r''` are passed in the form of payee's public key how does it not make such transaction capable to happen only once\or how is it checked and proved?
3. If a transaction can happen only one and payer needs to prove that he has funds for it how he can not be linked to that transaction?

**Tags:** zcash, zero-knowledge

> **Comments:**
> **username_0**: Dear moderators, please do care to explains why the hall on bloody earth question on the fundamentals of one of the top five blockchain systems (zcash) is offtopic on a website about blockchain?!?  
> **username_1**: See: https://bitcoin.stackexchange.com/help/on-topic  

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## 0 answers

