<p>In the paper, it mentions a third party, Chuck, who will resolve disputes.</p>

<blockquote>
  <p>(1): If customer (Alice) before receiving the product, signs 2-of-2
  transaction, then transaction is payable for merchant (Bob), but what
  happens if merchant (Bob) does not send the product to customer
  (Alice)?</p>
</blockquote>

<p>Assuming Bob only cared about getting paid, he would always sign a transaction which paid himself, so it does little good to require his signature. If alice signed a transaction which did not pay her, it would show good faith, if there was another party involved, Chuck. Chuck would require that the product be sent to Alice before the funds would be fully released to Bob. In this case it would be a 2-of-2 multisig script requiring Alice and Chuck, and requiring Alice to sign before Bob ships the package, for example.</p>

<blockquote>
  <p>(2): What happens if customer (Alice) denies to sign 2-of-2
  transaction before receiving the product, and after receiving the
  product also does not sign the transaction?</p>
</blockquote>

<p>Assuming this is a 2-of-2 requiring Alice and Chuck from above, then Bob would require Alice's signature before sending the product, that way the arbiter, Chuck would be responsible. Note that using a multisig script on blockchain to trace an external physical action would require trust (from both parties) in the arbiter, Chuck, and is not completely trustless.</p>

CC BY-SA 4.0
2019-02-04T13:45:40.783Z
Thank you, So we can conclude that transaction is not trust-less as it is claimed in the paper: _"PriWatt provides the means to form agreements or contracts without trusting other party via blockchain."_ They also mention use of **Chuck** as an **optional** entity: _"Alice and Bob **can** include Chuck as an arbitrator who can resolve disputes."_ That means parties either have to trust each other or trust a **Chuck** as a **trusted arbitrator**. Do you agree? Thanks
Questioner
CC BY-SA 4.0
2019-02-04T14:15:02.387Z
I also edited my question and mentioned my point of view on how multi-signature transactions can completely remove the trust between parties **without** using a **trusted Chuck as a trusted arbitrator**.
Questioner
CC BY-SA 4.0
2019-02-04T14:23:09.293Z
I would agree, the paper does not suggest any other methods to address those problems.
JBaczuk
CC BY-SA 4.0
2019-02-04T13:26:07.923Z
2019-02-04T13:26:07.923Z
JBaczuk
<p>This paper: (<a href="https://www.researchgate.net/publication/309097688_Security_and_Privacy_in_Decentralized_Energy_Trading_Through_Multi-Signatures_Blockchain_and_Anonymous_Messaging_Streams" rel="nofollow noreferrer">Link to paper</a>) introduces a blockchain based platform entitled <code>PriWatt</code> claiming (<em>in Section 2.5 MultiSignatures, page 3</em>):</p>

<blockquote>
  <p>"PriWatt provides the means to form agreements or contracts <strong>without
  trusting</strong> other party via blockchain."</p>
</blockquote>

<p>It continues:</p>

<blockquote>
  <p>"This is achieved through <strong>multi-signature</strong> transaction where minimum m
  of n keys must sign a transaction before tokens can be spend."</p>
</blockquote>

<p>(Similar to what we have in Bitcoin n-of-m transactions.)</p>

<p>However, my question is how to remove totally the <strong>trust</strong> when one party is <strong>payer</strong> and another party is <strong>payee</strong>?</p>

<p>I mean multi-signature transactions can be helpful when all of parties are <strong>payer</strong>. Assume for example a wallet in which a pay out transaction needs minimum m of n signatures. In this case that works.</p>

<p>But, if we consider the example of the paper (same section 2.5) as follows:</p>

<blockquote>
  <p>"For example, assume that a customer Alice wants to buy a product
  from a merchant Bob. They make a contract where Bob will not get paid
  until Alice gets a product. Similarly, Alice cannot get a product and
  keep her payment."</p>
</blockquote>

<p>However, in this scenario, merchant (Bob) signs <strong>2-of-2 transaction</strong>, where it has <strong>not</strong> been signed yet by customer (Alice). At this point:</p>

<p><strong>(1):</strong> If customer (Alice) <strong>before receiving the product</strong>, signs 2-of-2 transaction, then transaction is payable for merchant (Bob), but what happens if merchant (Bob) does not send the product to customer (Alice)?</p>

<p>Or</p>

<p><strong>(2)</strong>: What happens if customer (Alice) <strong>denies</strong> to sign 2-of-2 transaction <strong>before receiving the product</strong>, and after receiving the product also does not sign the transaction? </p>

<p>Does <strong>Multi_Signature</strong> transactions can fix this problem? <strong>Or</strong> merchant and customer need to <strong>trust</strong> each other?</p>

<p><strong>Edit:</strong> In my opinion, a <strong>Multi_Signature</strong> transaction can remove the <strong>trust</strong>, <strong><em>IF AND ONLY IF :</em></strong> all exchanged values between parties are <strong>internal</strong> (for example <strong>coin</strong> or any other <strong>parameter</strong> or <strong>token</strong> etc defined in the code as a <strong>variable</strong>.) <strong>Otherwise</strong> if one of values that is exchanged between parties would be an <strong>external asset</strong> (for example: a product or service like <strong>energy</strong> in the paper) then parties need to either trust each other or use a <strong>trusted</strong> arbitrator (<strong>trusted</strong> Chuck).</p>

<multi-signature><trust>
Does Multi_Signature transactions enable trust-less payments? (Edited)
Questioner
# Does Multi_Signature transactions enable trust-less payments? (Edited)

(Asked by: username_0 on 2019-02-04)

This paper: ([Link to paper](https://www.researchgate.net/publication/309097688_Security_and_Privacy_in_Decentralized_Energy_Trading_Through_Multi-Signatures_Blockchain_and_Anonymous_Messaging_Streams)) introduces a blockchain based platform entitled `PriWatt` claiming (*in Section 2.5 MultiSignatures, page 3*):

> "PriWatt provides the means to form agreements or contracts **without
> trusting** other party via blockchain."

It continues:

> "This is achieved through **multi-signature** transaction where minimum m
> of n keys must sign a transaction before tokens can be spend."

(Similar to what we have in Bitcoin n-of-m transactions.)

However, my question is how to remove totally the **trust** when one party is **payer** and another party is **payee**?

I mean multi-signature transactions can be helpful when all of parties are **payer**. Assume for example a wallet in which a pay out transaction needs minimum m of n signatures. In this case that works.

But, if we consider the example of the paper (same section 2.5) as follows:

> "For example, assume that a customer Alice wants to buy a product
> from a merchant Bob. They make a contract where Bob will not get paid
> until Alice gets a product. Similarly, Alice cannot get a product and
> keep her payment."

However, in this scenario, merchant (Bob) signs **2-of-2 transaction**, where it has **not** been signed yet by customer (Alice). At this point:

**(1):** If customer (Alice) **before receiving the product**, signs 2-of-2 transaction, then transaction is payable for merchant (Bob), but what happens if merchant (Bob) does not send the product to customer (Alice)?

Or

**(2)**: What happens if customer (Alice) **denies** to sign 2-of-2 transaction **before receiving the product**, and after receiving the product also does not sign the transaction?

Does **Multi\_Signature** transactions can fix this problem? **Or** merchant and customer need to **trust** each other?

**Edit:** In my opinion, a **Multi\_Signature** transaction can remove the **trust**, ***IF AND ONLY IF :*** all exchanged values between parties are **internal** (for example **coin** or any other **parameter** or **token** etc defined in the code as a **variable**.) **Otherwise** if one of values that is exchanged between parties would be an **external asset** (for example: a product or service like **energy** in the paper) then parties need to either trust each other or use a **trusted** arbitrator (**trusted** Chuck).

**Tags:** multi-signature, trust


---

## 1 answers

### Answer by username_1 on 2019-02-04. Score: 1 | Accepted answer

In the paper, it mentions a third party, Chuck, who will resolve disputes.

> (1): If customer (Alice) before receiving the product, signs 2-of-2
> transaction, then transaction is payable for merchant (Bob), but what
> happens if merchant (Bob) does not send the product to customer
> (Alice)?

Assuming Bob only cared about getting paid, he would always sign a transaction which paid himself, so it does little good to require his signature. If alice signed a transaction which did not pay her, it would show good faith, if there was another party involved, Chuck. Chuck would require that the product be sent to Alice before the funds would be fully released to Bob. In this case it would be a 2-of-2 multisig script requiring Alice and Chuck, and requiring Alice to sign before Bob ships the package, for example.

> (2): What happens if customer (Alice) denies to sign 2-of-2
> transaction before receiving the product, and after receiving the
> product also does not sign the transaction?

Assuming this is a 2-of-2 requiring Alice and Chuck from above, then Bob would require Alice's signature before sending the product, that way the arbiter, Chuck would be responsible. Note that using a multisig script on blockchain to trace an external physical action would require trust (from both parties) in the arbiter, Chuck, and is not completely trustless.

> **Comments:**
> **username_0**: Thank you, So we can conclude that transaction is not trust-less as it is claimed in the paper: _"PriWatt provides the means to form agreements or contracts without trusting other party via blockchain."_ They also mention use of **Chuck** as an **optional** entity: _"Alice and Bob **can** include Chuck as an arbitrator who can resolve disputes."_ That means parties either have to trust each other or trust a **Chuck** as a **trusted arbitrator**. Do you agree? Thanks  
> **username_0**: I also edited my question and mentioned my point of view on how multi-signature transactions can completely remove the trust between parties **without** using a **trusted Chuck as a trusted arbitrator**.  
> **username_1**: I would agree, the paper does not suggest any other methods to address those problems.  

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