<p>In Confidental Transactions, like they are implemented in Blockstream Liquid, transactions have an explicit (plain text) fee field, and the rule is that sum(output_commitments) + commit(fee) = sum(input_commitments).</p>
<p>Without clear text fee field, miners indeed would not be able to claim the difference between outputs and inputs.</p>

CC BY-SA 4.0
2021-07-10T03:55:38.483Z
Thank You. there are too many followup questions on this! I will post another question.
Cisco Mmu
CC BY-SA 4.0
2021-07-09T15:46:53.357Z
2021-07-09T15:46:53.357Z
Pieter Wuille
<p>Fees in liquid are explicitly defined as an output, as describing them as the deficit between input and output is impossible when the values are unknown to the validator.</p>

CC BY-SA 4.0
2021-07-10T03:57:47.923Z
Thank You. there are too many followup questions on this! I will post another question.
Cisco Mmu
CC BY-SA 4.0
2021-07-09T15:48:27.853Z
2021-07-09T15:48:27.853Z
Claris
<p>Is there any transaction fee for Confidential Transactions in the Liquid Network?</p>
<p>In the UTXO model, Alice has 10 btc. She sends 1 btc to Bob, 8.999 btc as return change, and 0.001 as fee.</p>
<pre><code>Input :  10     btc (Alice)  
Outputs:  1     btc (Bob)  
          8.999 btc (Alice)
</code></pre>
<p>The remaining balance of 0.001 is considered the fee but not recorded as a transaction output.</p>
<p>Is this the same for Confidential Transaction?</p>
<pre><code>Input : C1 = Commit (10btc)
Output: C2 = Commit (1 btc)
        C3 = Commit (8.999 btc)
        C4 = Commit (0.001 btc)
</code></pre>
<p>C1 = C2 + C3 + C4</p>
<p>If C4 is not there, then can we assume C4 = C1 - C2 - C3.</p>
<p>But is there any coinbase tx in Liquid to take the C4 fee?
I 'm confused.</p>

<transaction-fees><confidential-transactions><liquid>
Transaction Fee in Confidential Transactions
Cisco Mmu
# Transaction Fee in Confidential Transactions

(Asked by: username_0 on 2021-07-09)

Is there any transaction fee for Confidential Transactions in the Liquid Network?
In the UTXO model, Alice has 10 btc. She sends 1 btc to Bob, 8.999 btc as return change, and 0.001 as fee.
Input :  10     btc (Alice)  
Outputs:  1     btc (Bob)  
          8.999 btc (Alice)

The remaining balance of 0.001 is considered the fee but not recorded as a transaction output.
Is this the same for Confidential Transaction?
Input : C1 = Commit (10btc)
Output: C2 = Commit (1 btc)
        C3 = Commit (8.999 btc)
        C4 = Commit (0.001 btc)

C1 = C2 + C3 + C4
If C4 is not there, then can we assume C4 = C1 - C2 - C3.
But is there any coinbase tx in Liquid to take the C4 fee?
I 'm confused.

**Tags:** transaction-fees, confidential-transactions, liquid


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## 2 answers

### Answer by username_1 on 2021-07-09. Score: 2

In Confidental Transactions, like they are implemented in Blockstream Liquid, transactions have an explicit (plain text) fee field, and the rule is that sum(output\_commitments) + commit(fee) = sum(input\_commitments).

Without clear text fee field, miners indeed would not be able to claim the difference between outputs and inputs.

> **Comments:**
> **username_0**: Thank You. there are too many followup questions on this! I will post another question.  

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### Answer by username_2 on 2021-07-09. Score: 2

Fees in liquid are explicitly defined as an output, as describing them as the deficit between input and output is impossible when the values are unknown to the validator.

> **Comments:**
> **username_0**: Thank You. there are too many followup questions on this! I will post another question.  

---

