Ethereum: Should the BIP 39 mnemonic sentence checksum be eliminated from the standard? Does it do more harm than good?

The Ethereum Community Debate: Is the BIP 39 Checksum a Security Risk or a Convenience?

The development and maintenance of the Ethereum blockchain have sparked an intense debate among developers, researchers, and users about the role of the Bitcoin Improvement Proposal (BIP) 39 mnemonic set checksum. This article examines the arguments for and against eliminating the BIP 39 checksum from the standard, as well as its potential security implications.

What is the BIP 39 checksum?

The BIP 39 mnemonic set is a cryptographically secure way to store and verify private keys. It generates a 12-word, 28-character (16 letters, 8 digits, and 4 special characters) phrase that serves as the password for each individual Ethereum account. The checksum is calculated from the first five words of the mnemonic phrase, ensuring that any change or alteration to the original phrase results in the same checksum.

Why eliminate the BIP 39 checksum?

Proponents argue that the BIP 39 checksum, when combined with other factors, such as the Ethereum network’s Random Number Generator (RNG), can pose security risks. In a secure system, the RNG should be able to generate new numbers for each account without being influenced by external factors such as the mnemonic phrase. However, the current implementation has an inherent weakness: if the checksum changes due to a change in the mnemonic phrase, the resulting checksum may not match the original one, potentially allowing unauthorized access to accounts.

Arguments against elimination

Critics counter that eliminating or optionalizing the BIP 39 checksum would result in:

• Increased complexity: Users and developers alike would have to relearn how to generate and verify mnemonics, potentially leading to increased complexity.

• Inefficiency: The current implementation allows users to store a large number of mnemonics, which may be impractical for people with extensive knowledge of cryptography.

• Security risks: As mentioned above, the checksum itself may not provide sufficient security when combined with other factors such as a weak RNG.

Arguments for the optional BIP 39 checksum

Others argue that the optional BIP 39 checksum would allow users to choose how they want to store and verify their private keys. This approach would:

• Promote flexibility:

  

  Users can choose from different mnemonic lengths and implementations, allowing them to select the one that best fits their needs.

• Reduce complexity: Providing an option allows users to avoid relearning complex cryptographic concepts or using a fixed-length mnemonic.

Conclusion

The BIP 39 checksum debate is ongoing and there are valid arguments on both sides. While eliminating the checksum entirely may seem attractive due to potential security risks, it is important to consider the following:

• Security trade-offs: The current implementation has proven sufficient for most users, and making the checksum optional would not significantly impact security.

• User preferences: Providing an option allows users to choose their preferred approach, ensuring they can continue to use a mnemonic of their choice.

Ultimately, the question of whether or not to remove the BIP 39 checksum from the standard remains a matter of debate within the Ethereum community. As the ecosystem evolves and grows, it is important to find a balance between security and usability.

Recommendations

To mitigate potential security risks associated with the current implementation, the following recommendations can be considered:

• Improve RNG: The Ethereum team could explore ways to improve the performance and randomness of the random number generator.

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