> For the complete documentation index, see [llms.txt](https://homepage.gitbook.io/witswap/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://homepage.gitbook.io/witswap/about-witnet/defense-over-protocol-attacks.md).

# Defense over Protocol Attacks

Source: https\://witnet.io/about

The most frequent attacks aimed at PoW and PoS consensus mechanisms in blockchains have been thoroughly analysed in recent years, but how does a reputation system based blockchain defend against these attacks? In our [blog in Medium](https://medium.com/witnet) you can find specific explanations, but in summary:

* **Sybil attacks**: The reputation system works very well against this attack since it requires the sybils to work on the network to gain sufficient influence. In addition, a collateral fee is required when solving a data request, making the attack economically inviable.
* **Eclipse attacks**: In order to avoid an attacker monopolizing all the connections of a node, a P2P bucketing system has been implemented. More details can be found in this [post of Medium](https://medium.com/witnet/the-p2p-bucketing-system-in-witnet-d893dce4b8c5).
* **Bribery attacks**: The implementation of the collateral fee makes any bribe very expensive, for more information, take a look on this [post](https://medium.com/witnet/deterring-bribery-attacks-on-decentralized-oracle-networks-5bcf87d2cb22).
* **Majority attacks**: The implementation of Witnet guarantees that in order to perform a majority attack, the attacker would need to hold 51% of the total reputation. This is an extremely unlikely scenario, even where reputation is pooled.
* **DDoS attacks**: Witnet implements Dandelion to obfuscate the relation between IPs and Public keys, making DDos attacks near impossible.