Wasabi and Samourai Wallets - Reading Assignment

Privacy Coins - Ultimate Course
#223

• How are Wasabi and Samourai wallets related?

At one point in time, Samourai and Wasabi were the same application.
Lead developers TDevD (Samourai) and nopara73 (Wasabi) worked together on building an implementation of long-standing bitcoin privacy tech CoinJoin called ZeroLink.

“We just had a difference in implementation desire,” said SW. “So we split. We forked the project and just implemented it the way we wanted to implement it.”

• What is a ‘Sybil attack’?

A small number of users falsifies new identities and pretends to be much larger in number. This would mean that the anonymity set, or crowd, in which a user can hide their bitcoin transactions is not actually as large as Wasabi suggests.

• How does Samourai protect against Sybil attacks?

Samourai’s implementation of ZeroLink (called Whirlpool) has a different pricing mechanism than Wasabi, though this is not the only difference between the two wallet applications. As a result, SW maintains that Whirlpool makes it more expensive for malicious actors in the system to break the anonymity of other users through a Sybil attack.

• What ‘trade-off’ does Samourai make in order to achieve #3? Why is Wasabi critical of this?

Samourai’s implementation of ZerLink has a different pricing mechanism than Wasabi.
Wasabi’s Adam Ficsor, who goes by the alias nopara73, counters that divvying up costs later on in the process is actually more “cost-effective” and points out that anonymity using Whirlpool can always be broken given that Samourai relies on a centralized, backend server to process users’ extended public keys.

#224

  1. How are Wasabi and Samourai wallets related?
    Both are Bitcoin wallets with a focus on privacy, originating from the same application but have evolved separately.

  2. What is a ‘Sybil attack’?
    It’s when an attacker creates multiple fake identities in a network, potentially compromising anonymity.

  3. How does Samourai protect against Sybil attacks?
    Samourai uses a fee model that makes Sybil attacks costly, thus deterring attackers.

  4. What ‘trade-off’ does Samourai make in order to achieve #3? Why is Wasabi critical of this?
    Samourai uses a centralized server to process users’ public keys, which Wasabi criticizes as it introduces a point of trust and potential privacy compromise.

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#225

Relationship Between Wasabi and Samourai Wallets

Samourai and Wasabi wallets are both Bitcoin privacy wallets that initially shared the same foundation. Both wallets were developed by contributors who implemented CoinJoin technology under the ZeroLink framework. However, due to different design preferences, the developers split and created their own versions: Samourai (Whirlpool) and Wasabi.
What is a Sybil Attack?

A Sybil attack occurs when an attacker creates multiple fake identities to manipulate a network. In the context of Bitcoin privacy wallets, this means creating numerous fake participants in a mixing pool to reduce the effectiveness of anonymizing transactions.

Samourai’s Protection Against Sybil Attacks

Samourai attempts to protect against Sybil attacks by making it more expensive for attackers to create fake identities. This involves using specific pricing mechanisms to increase the cost of participating in the mixing process, thereby discouraging attackers from creating multiple fake identities.

Trade-off and Criticism from Wasabi

To achieve this protection, Samourai relies on a centralized server to manage and process transactions. This means users must trust Samourai not to misuse their data, such as selling public key information to third parties. Wasabi criticizes this approach because it believes that centralization creates a potential single point of failure and goes against the principle of decentralization that enhances security and privacy. Wasabi prefers a more decentralized method that does not require such trust in a single entity.