Edit: Because you don't need to actually crack the seed phrase but rather find a private key from public key, it holds that 12 words generated just as randomly is as secure as 24 words. They will both produce a 128bit secret key which means they are just as secure as each-other regardless of the permutations of the seed words. Credit to Pieter for the fix.

Because you don't need to actually crack the seed phrase but rather find a private key from public key, it holds that 12 words generated just as randomly is as secure as 24 words. They will both produce a 128bit secret key which means they are just as secure as each-other regardless of the permutations of the seed words. Credit to Pieter for the fix.

The security of a signature and the security of your private key entropy are actually quite different. If your private key is easily guessable it doesn't really matter what bit security secp256k1 has because someone can brute-force your key. Adding more words to the mnemonic increases the entropy involved in generating the private key, 12 word phrases are basically 'good enough' as far as I understand but I doubt they are 'just as secure' as 24 word ones. I think the main benefit is it is easier to remember and does not sacrifice too much in terms of entropy, but the chance of a collision with less permutations of seed phrase words has to be higher even if it is close to zero in the first place.

Edit: Because you don't need to actually crack the seed phrase but rather find a private key from public key, it holds that 12 words generated just as randomly is as secure as 24 words. They will both produce a 128bit secret key which means they are just as secure as each-other regardless of the permutations of the seed words. Credit to Pieter for the fix.