<p>From what I understand, Proof of Activity and Proof of Stake are methods of preventing a 51% attack.</p>

<p>Proof of Stake basically means that the people that hold the most coins sign the blocks that will be part of the block chain. This means that the people that have the most to lose from a 51% attack will do their best to prevent it and not risk losing their money. However, this also means that the rich users can control the network.</p>

<p>Proof of Activity from what I gather is a method of selecting a random peer from the entire network to sign a new block that would be temper-proof. This would mean that a 51% attack could not execute too well, as it couldn't predict who the signing peer be in the future.</p>

<p>The latter idea appears to be better for preventing attacks on the network, providing there are no logical problems in there. However, I have not studied either of the two methods in greater detail so I might be wrong.</p>

CC BY-SA 3.0
2012-09-17T20:27:38.490Z
So would it be correct to say that "In PoA a single output/satoshi is selected every block that has the permission to sign it (but doesn't have to)" and "In PoS multiple signatures/votes are allowed every 'Stake block', and these votes are tallied to resolve conflicts" ? In PoA, we randomly appoint a dictator per block (by BTC ownership weight), while PoS uses a majority vote. If this is indeed the difference, I'm not sure why this difference makes PoA so much better than PoS.
ripper234
CC BY-SA 3.0
2012-09-17T22:42:56.907Z
@ripper234 I guess that PoA is less centralised and doesn't rely on some key people to be present, whereas in PoS you put the future of the project in the hands of just a few individuals.
ThePiachu
CC BY-SA 3.0
2012-09-18T05:04:49.300Z
Then I don't understand. What in PoS makes it more centralized?
ripper234
CC BY-SA 3.0
2012-09-18T06:18:20.787Z
@ripper234 Relying on a few key users to be present to sign the new blocks. Those key entities could be targeted and if they all become compromised, your network could shut down.
ThePiachu
CC BY-SA 3.0
2012-09-18T06:25:26.423Z
In what way does PoS "rely on a few key users" and PoA does not?
ripper234
CC BY-SA 3.0
2012-09-18T06:54:13.770Z
@ripper234 From what I gather, in PoS the richest keypairs are used to sign new blocks (for example, StronCoin's "millionaire accounts"), whereas in PoA random active keypairs are used to sign the blocks. I might be wrong on this, however.
ThePiachu
CC BY-SA 3.0
2012-09-18T08:06:04.480Z
let us [continue this discussion in chat](http://chat.stackexchange.com/rooms/5858/discussion-between-ripper234-and-thepiachu)
ripper234
CC BY-SA 3.0
2012-09-17T15:42:11.537Z
2012-09-17T15:42:11.537Z
ThePiachu
<p>La principal diferencia entre Proof of Activity (<strong>PoA</strong>) y Proof of Stake (<strong>PoS</strong>) radica en cómo cada uno aborda la seguridad y la validación de las transacciones en una blockchain. Mientras que PoS selecciona validadores en función de la cantidad de criptomonedas que poseen y están dispuestos a &quot;apostar&quot; (staking), PoA combina elementos de Proof of Work (PoW) y PoS para mejorar la seguridad y la descentralización.</p>
<p>En <strong>PoS</strong>, los validadores son elegidos según su participación en la red, lo que puede llevar a una centralización, ya que quienes poseen más monedas tienen mayor influencia. Además, PoS enfrenta desafíos como el problema de &quot;nada en juego&quot;, donde los validadores pueden validar múltiples cadenas sin costo, potencialmente comprometiendo la seguridad de la red.</p>
<p>Por otro lado, <strong>PoA</strong> busca mitigar estos problemas combinando PoW y PoS. En PoA, los mineros utilizan PoW para generar plantillas de bloques vacíos. Una vez creadas, se seleccionan aleatoriamente validadores, basándose en PoS, para firmar y completar estos bloques con las transacciones. Este enfoque híbrido aprovecha la seguridad de PoW y la eficiencia energética de PoS, reduciendo la posibilidad de centralización y mejorando la resistencia a ataques.</p>
<p>Además las ventajas, PoA aporta un nivel adicional de flexibilidad y adaptabilidad frente a limitaciones energéticas y de seguridad. La combinación de PoW y PoS hace que el sistema sea más resistente a ciertos tipos de ataques, como el ataque del 51%, ya que el proceso de selección de validadores es en parte aleatorio y está basado en el trabajo de minería previo. Esto implica que un atacante necesitaría controlar tanto la mayoría del poder de minado como una proporción significativa de los activos de la red para tomar el control, lo cual haría el ataque más difícil y costoso de realizar.</p>
<p>En otras palabras, <strong>PoA</strong> intenta resolver las limitaciones de PoS, como la centralización y el problema de &quot;nada en juego&quot;, al integrar la seguridad de PoW con la eficiencia de PoS, creando un sistema más equilibrado y seguro para la validación de transacciones en la blockchain.</p>
<p>Referencias:</p>
<ol>
<li>Bentov, I., Lee, C., Mizrahi, A., &amp; Rosenfeld, M. (2014). Proof of
Activity: Extending Bitcoin's Proof of Work via Proof of Stake.
Recuperado el 12 de noviembre de 2024, de <a href="https://eprint.iacr.org/2014/452" rel="nofollow noreferrer">https://eprint.iacr.org/2014/452</a></li>
<li>Binance Academy. (2018, 12 de diciembre). Proof of Work (PoW) vs.
Proof of Stake (PoS). Recuperado el 12 de noviembre de 2024, de
<a href="https://academy.binance.com/es/articles/proof-of-work-vs-proof-of-stake" rel="nofollow noreferrer">https://academy.binance.com/es/articles/proof-of-work-vs-proof-of-stake</a></li>
<li>Coinbase. (s.f.). Prueba de trabajo (PoW) vs. Prueba de
participación (PoS): ¿Cuál es la diferencia?. Recuperado el 12 de noviembre de 2024, de
<a href="https://www.coinbase.com/es-es/learn/crypto-basics/proof-of-work-pow-vs-proof-of-stake-pos-what-is-the-difference" rel="nofollow noreferrer">https://www.coinbase.com/es-es/learn/crypto-basics/proof-of-work-pow-vs-proof-of-stake-pos-what-is-the-difference</a></li>
<li>Nervos. (2023, 19 de julio). Proof-of-Work vs. Proof-of-Stake:
Desentrañando las Diferencias Clave. Recuperado el 12 de noviembre de 2024, de
<a href="https://www.nervos.org/es/knowledge-base/pow_vs_pos_unravelling_%28explainCKBot%29" rel="nofollow noreferrer">https://www.nervos.org/es/knowledge-base/pow_vs_pos_unravelling_%28explainCKBot%29</a></li>
<li>BitDegree. (s.f.). ¿Qué es Proof-of-Work vs Proof-of-Stake?
Diferencias Importantes. Recuperado el 12 de noviembre de 2024, de
<a href="https://es.bitdegree.org/crypto/aprender/que-es-proof-of-work-vs-proof-of-stake" rel="nofollow noreferrer">https://es.bitdegree.org/crypto/aprender/que-es-proof-of-work-vs-proof-of-stake</a></li>
</ol>

CC BY-SA 4.0
2024-11-13T05:01:42.390Z
2024-11-13T05:01:42.390Z
Enrique Ramírez
<p>The key difference between Proof of Activity (PoA) and Proof of Stake (PoS) lies in how they combine elements from both Proof of Work (PoW) and Proof of Stake to achieve consensus and secure the blockchain.</p>
<p>Proof of Stake (PoS)
Concept: In PoS, validators are chosen to create new blocks and validate transactions based on the amount of cryptocurrency they &quot;stake&quot; (lock up as collateral) in the network. The more coins a participant holds and stakes, the higher the chances they will be chosen to validate transactions and earn rewards.
Security Model: PoS relies on economic incentives. Validators are financially motivated to act honestly, as malicious actions can result in the loss of their staked coins.
Energy Efficiency: PoS is more energy-efficient than PoW because it does not require intensive computational work to validate transactions.
Proof of Activity (PoA)
Concept: PoA is a hybrid model that combines elements of PoW and PoS. In PoA, miners initially perform PoW to mine an &quot;empty&quot; block header, which doesn’t yet contain transactions. Once this header is mined, a set of validators (chosen based on PoS) is randomly selected to sign the block. Only after a certain number of validators sign it does the block become a valid part of the blockchain.
Security Model: PoA leverages both computational work (for mining the header) and the economic stake of validators (for signing the block). This mix aims to enhance security by making attacks more costly, as an attacker would need both substantial computing power and a large stake.
Energy Efficiency: Although PoA still involves some PoW, it typically uses less energy than a pure PoW system since it only requires PoW for mining the header, not for validating every transaction.
Summary
PoS is a straightforward staking-based model, where block creation relies on the economic stake.
PoA blends PoW and PoS, with PoW used initially to generate a block header and PoS used to validate it, aiming to balance security and efficiency.</p>

CC BY-SA 4.0
2024-11-13T11:13:23.247Z
2024-11-13T11:13:23.247Z
Pooja
<p>coblee (Litecoin creator) <a href="https://bitcointalk.org/index.php?topic=102355" rel="noreferrer">suggested a new Proof of Activity</a> method, to complement <a href="https://en.bitcoin.it/wiki/Proof_of_work" rel="noreferrer">Proof of Work</a>, instead of using <a href="https://en.bitcoin.it/wiki/Proof_of_Stake" rel="noreferrer">Proof of Stake</a> (oh my!)</p>

<p>Can someone provide a tl;dr of what is the key problem in PoS that PoA is trying to solve, and how does it solve it?</p>

<blockchain><alternatives><proof-of-stake>
What is the key difference between the Proof of Activity proposal and Proof of Stake?
ripper234
# What is the key difference between the Proof of Activity proposal and Proof of Stake?

(Asked by: username_0 on 2012-09-17)

coblee (Litecoin creator) [suggested a new Proof of Activity](https://bitcointalk.org/index.php?topic=102355) method, to complement [Proof of Work](https://en.bitcoin.it/wiki/Proof_of_work), instead of using [Proof of Stake](https://en.bitcoin.it/wiki/Proof_of_Stake) (oh my!)

Can someone provide a tl;dr of what is the key problem in PoS that PoA is trying to solve, and how does it solve it?

**Tags:** blockchain, alternatives, proof-of-stake


---

## 3 answers

### Answer by username_1 on 2012-09-17. Score: 2 | Accepted answer

From what I understand, Proof of Activity and Proof of Stake are methods of preventing a 51% attack.

Proof of Stake basically means that the people that hold the most coins sign the blocks that will be part of the block chain. This means that the people that have the most to lose from a 51% attack will do their best to prevent it and not risk losing their money. However, this also means that the rich users can control the network.

Proof of Activity from what I gather is a method of selecting a random peer from the entire network to sign a new block that would be temper-proof. This would mean that a 51% attack could not execute too well, as it couldn't predict who the signing peer be in the future.

The latter idea appears to be better for preventing attacks on the network, providing there are no logical problems in there. However, I have not studied either of the two methods in greater detail so I might be wrong.

> **Comments:**
> **username_0**: So would it be correct to say that "In PoA a single output/satoshi is selected every block that has the permission to sign it (but doesn't have to)" and "In PoS multiple signatures/votes are allowed every 'Stake block', and these votes are tallied to resolve conflicts" ? In PoA, we randomly appoint a dictator per block (by BTC ownership weight), while PoS uses a majority vote. If this is indeed the difference, I'm not sure why this difference makes PoA so much better than PoS.  
> **username_1**: @username_0 I guess that PoA is less centralised and doesn't rely on some key people to be present, whereas in PoS you put the future of the project in the hands of just a few individuals.  
> **username_0**: Then I don't understand. What in PoS makes it more centralized?  
> **username_1**: @username_0 Relying on a few key users to be present to sign the new blocks. Those key entities could be targeted and if they all become compromised, your network could shut down.  
> **username_0**: In what way does PoS "rely on a few key users" and PoA does not?  
> **username_1**: @username_0 From what I gather, in PoS the richest keypairs are used to sign new blocks (for example, StronCoin's "millionaire accounts"), whereas in PoA random active keypairs are used to sign the blocks. I might be wrong on this, however.  
> **username_0**: let us [continue this discussion in chat](http://chat.stackexchange.com/rooms/5858/discussion-between-username_0-and-username_1)  

---

### Answer by username_2 on 2024-11-13. Score: -2

La principal diferencia entre Proof of Activity (**PoA**) y Proof of Stake (**PoS**) radica en cómo cada uno aborda la seguridad y la validación de las transacciones en una blockchain. Mientras que PoS selecciona validadores en función de la cantidad de criptomonedas que poseen y están dispuestos a "apostar" (staking), PoA combina elementos de Proof of Work (PoW) y PoS para mejorar la seguridad y la descentralización.

En **PoS**, los validadores son elegidos según su participación en la red, lo que puede llevar a una centralización, ya que quienes poseen más monedas tienen mayor influencia. Además, PoS enfrenta desafíos como el problema de "nada en juego", donde los validadores pueden validar múltiples cadenas sin costo, potencialmente comprometiendo la seguridad de la red.

Por otro lado, **PoA** busca mitigar estos problemas combinando PoW y PoS. En PoA, los mineros utilizan PoW para generar plantillas de bloques vacíos. Una vez creadas, se seleccionan aleatoriamente validadores, basándose en PoS, para firmar y completar estos bloques con las transacciones. Este enfoque híbrido aprovecha la seguridad de PoW y la eficiencia energética de PoS, reduciendo la posibilidad de centralización y mejorando la resistencia a ataques.

Además las ventajas, PoA aporta un nivel adicional de flexibilidad y adaptabilidad frente a limitaciones energéticas y de seguridad. La combinación de PoW y PoS hace que el sistema sea más resistente a ciertos tipos de ataques, como el ataque del 51%, ya que el proceso de selección de validadores es en parte aleatorio y está basado en el trabajo de minería previo. Esto implica que un atacante necesitaría controlar tanto la mayoría del poder de minado como una proporción significativa de los activos de la red para tomar el control, lo cual haría el ataque más difícil y costoso de realizar.

En otras palabras, **PoA** intenta resolver las limitaciones de PoS, como la centralización y el problema de "nada en juego", al integrar la seguridad de PoW con la eficiencia de PoS, creando un sistema más equilibrado y seguro para la validación de transacciones en la blockchain.

Referencias:

1. Bentov, I., Lee, C., Mizrahi, A., & Rosenfeld, M. (2014). Proof of
   Activity: Extending Bitcoin's Proof of Work via Proof of Stake.
   Recuperado el 12 de noviembre de 2024, de <https://eprint.iacr.org/2014/452>
2. Binance Academy. (2018, 12 de diciembre). Proof of Work (PoW) vs.
   Proof of Stake (PoS). Recuperado el 12 de noviembre de 2024, de
   <https://academy.binance.com/es/articles/proof-of-work-vs-proof-of-stake>
3. Coinbase. (s.f.). Prueba de trabajo (PoW) vs. Prueba de
   participación (PoS): ¿Cuál es la diferencia?. Recuperado el 12 de noviembre de 2024, de
   <https://www.coinbase.com/es-es/learn/crypto-basics/proof-of-work-pow-vs-proof-of-stake-pos-what-is-the-difference>
4. Nervos. (2023, 19 de julio). Proof-of-Work vs. Proof-of-Stake:
   Desentrañando las Diferencias Clave. Recuperado el 12 de noviembre de 2024, de
   <https://www.nervos.org/es/knowledge-base/pow_vs_pos_unravelling_%28explainCKBot%29>
5. BitDegree. (s.f.). ¿Qué es Proof-of-Work vs Proof-of-Stake?
   Diferencias Importantes. Recuperado el 12 de noviembre de 2024, de
   <https://es.bitdegree.org/crypto/aprender/que-es-proof-of-work-vs-proof-of-stake>


---

### Answer by username_3 on 2024-11-13. Score: -2

The key difference between Proof of Activity (PoA) and Proof of Stake (PoS) lies in how they combine elements from both Proof of Work (PoW) and Proof of Stake to achieve consensus and secure the blockchain.

Proof of Stake (PoS)
Concept: In PoS, validators are chosen to create new blocks and validate transactions based on the amount of cryptocurrency they "stake" (lock up as collateral) in the network. The more coins a participant holds and stakes, the higher the chances they will be chosen to validate transactions and earn rewards.
Security Model: PoS relies on economic incentives. Validators are financially motivated to act honestly, as malicious actions can result in the loss of their staked coins.
Energy Efficiency: PoS is more energy-efficient than PoW because it does not require intensive computational work to validate transactions.
Proof of Activity (PoA)
Concept: PoA is a hybrid model that combines elements of PoW and PoS. In PoA, miners initially perform PoW to mine an "empty" block header, which doesn’t yet contain transactions. Once this header is mined, a set of validators (chosen based on PoS) is randomly selected to sign the block. Only after a certain number of validators sign it does the block become a valid part of the blockchain.
Security Model: PoA leverages both computational work (for mining the header) and the economic stake of validators (for signing the block). This mix aims to enhance security by making attacks more costly, as an attacker would need both substantial computing power and a large stake.
Energy Efficiency: Although PoA still involves some PoW, it typically uses less energy than a pure PoW system since it only requires PoW for mining the header, not for validating every transaction.
Summary
PoS is a straightforward staking-based model, where block creation relies on the economic stake.
PoA blends PoW and PoS, with PoW used initially to generate a block header and PoS used to validate it, aiming to balance security and efficiency.


---

