Do 24-Word Bitcoin Seed Phrases Offer Stronger Security

The length of the seed phrase is typically not the primary security concern; instead, it’s how users store and safeguard it.

The seed phrase, a string of characters that acts as the master key to accessing and retrieving digital assets, is the foundation of crypto wallet security. Although 12-word and 24-word seed phrases are frequently employed, there has been discussion in the crypto world on the distinctions in their security implications.

Numerous cryptocurrency wallets have adopted the 12-word seed phrase as their standard, which offers 128 bits of entropy. With present technology, this amount of entropy equates to an enormous number of conceivable combinations, making brute-force attacks extremely difficult to execute. 24-word seed phrases, on the other hand, double the theoretical security with 256 bits of entropy.

The practical security benefit of utilizing a 24-word phrase instead of a 12-word one is less than the statistics imply. The elliptic curve encryption used by Bitcoin (secp256k1) has an adequate security of 128 bits. This means that an attacker cannot lower the number of steps needed to generate a private key from a public key below this threshold, regardless of the length of the seed phrase.

Twelve words are sufficient security

The CEO of Blockstream and well-known cryptographer Adam Back has defended the appropriateness of 12-word seeds, claiming that they offer sufficient protection for most users. More than a necessity for increased security, the move to 24-word phrases in some hardware wallets, like Trezor, was motivated by implementation requirements.

The length of the seed phrase is typically not the primary security concern; instead, it’s how users store and safeguard it. Phishing attempts, physical theft, and user error during storage can affect 12- and 24-word phrases. A 12-word sentence kept safely is significantly more potent than a 24-word one handled haphazardly.

When it comes to user experience, 12-word sentences have clear benefits. They are less likely to be entered incorrectly during wallet recovery procedures since they are simpler to write down, recall, and enter. This simplicity might be vital in high-stress scenarios where users need to access their funds swiftly.

Theoretically, 24-word phrases offer higher security; however, in the context of current cryptographic standards, the gains are negligible. Their added complexity could result in more user errors, jeopardizing security.

Using 24-word phrases as an additional safety precaution for high-value or institutional accounts could be reasonable. For the average user, however, a properly secured 12-word seed phrase provides more than enough protection against potential threats.

Where it could be preferable to use 24 words seed phrase

Renowned cryptographer and b-money inventor Wei Dai provides a balanced viewpoint on the security consequences of different seed phrase lengths. He notes that the situation changes considerably in a multi-user setting, even though a 12-word seed phrase (128 bits of entropy) is theoretically sufficient for single-user security when hashed to a 256-bit key.

Dai notes that in real-world deployments, when millions of users create wallets, this architecture can only support up to 2^64 keys before running the risk of collisions. His observation highlights the significance of considering more thorough security models beyond single-user settings and specific security boundaries.

The security protocols around the cryptocurrency industry have changed along with it. Depending on their security requirements and risk assessments, users can select from 12, 18, or 24 words using variable entropy choices offered by some wallet providers. Specific hardware wallets provide additional options, like Shamir Secret Sharing, that require 20 or 33 words.

A user’s unique requirements, degree of technological familiarity, and risk tolerance should be considered when selecting between a 12- and 24-word seed phrase. Although users may feel more psychologically secure with a longer phrase, they should remember that, regardless of length, managing and storing their seed phrase carefully is the most crucial step in safeguarding their digital assets.

Educating people on the appropriate methods for managing seed phrases is still essential. Regardless of the word count—12, 18, 20, 24, or 33—users need to prioritize safe storage techniques like hardware wallets and offline backups to protect their digital assets in an ever-more complicated digital world.