What Is The Difference Between Permissionless and Censorship Resistant?

8 Sept

A discussion on Stacker News delved into the distinction between two key terms frequently associated with Bitcoin: permissionless and censorship resistant. While these terms are often used interchangeably, especially when discussing Bitcoin's decentralized nature, the conversation revealed subtle but important differences.

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At its core, permissionless means that individuals do not need authorization from any central authority to participate in the system. In the context of Bitcoin, this applies to accessing the network, validating transactions, and mining. Users can engage with the Bitcoin protocol without requiring approval from any third party. As user @Golu summarized, "Permissionless means when you don't need to comply."

In contrast, traditional banking systems, for example, require permission at every step—whether to open an account, make transactions, or withdraw money. In the Bitcoin world, permissionless access means that any individual with an internet connection or even a Blockstream Satellite setup can interact with the network freely.

On the other hand, censorship resistance refers to the network's ability to protect against interference, ensuring that no transactions can be blocked, reversed, or altered by a third party. This attribute allows users to transact without fear of governmental or institutional control. As @BTCLNAT aptly pointed out, censorship resistance encompasses three elements: the freedom to transact, protection against confiscation, and the immutability of transactions.

Bitcoin’s decentralized nature makes it difficult for any single entity to censor transactions. Even if certain miners or nodes attempt to block specific transactions, the network’s design ensures that another miner can eventually include the transaction in a block. Thus, censorship resistance offers a safeguard against attempts to prevent the free flow of transactions within the network.

Permissionless vs. Censorship Resistant: Are They Synonymous?

Several participants in the thread debated whether these two terms are synonymous. User @TheBitcoinPhysio wrestled with this, noting, “Permissionless means I don’t need to ask anyone, and censorship resistance means nobody can change or hide or stop my... money.”

Other users also highlighted the intertwined nature of the two concepts. If the system is truly permissionless, should it not also be censorship resistant? @Scoresby, the original poster, argued that permissionless refers to joining the network, while censorship resistance relates to how transactions are handled within the network.

Are We Overcomplicating Things?

Some in the discussion, such as @nostrman and @heuristics, suggested that there is technically no difference between the two terms when it comes to Bitcoin. As @k00b put it, “Censorship and the opportunity to deny permission happen at the same time.”

However, @Scoresby presented an interesting scenario where Bitcoin mining becomes more centralized and miners are pressured by governments to exclude transactions associated with certain addresses, like those on the OFAC sanctions list. In such a case, Bitcoin would technically still be permissionless, as users could run nodes and hold keys without permission, but it might lose its censorship resistance if transactions from blacklisted addresses were consistently blocked. This hypothetical demonstrates how the terms might diverge in practice, depending on the specific scenario.

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