The mnemonic seed is simply a way to represent a secret key for your wallet on the blockchain. As long as you backup your mnemonic seed, you can restore you wallet even without your wallet files.
A Catalyst mnemonic seed consists of 25 words.
Those 25 words are taken out of a dictionary, which can be language specific sometimes but usually is kept in english.
Catalyst’s dictionary for the english mnemonic seed words can be found here:
Math behind mnemonic seed
Since those 25 words are open available, it can cross once mind, that those mnemonic seed might not be safe. But lets have a closer look on the math behind it…
We have 25 randomly chosen words from the dictionary. In the dictionary are up to 1626 words available. This means if we forget one of our 25 words, we have to guess up to 1626 times to recreate our mnemonic seed. Seems quite doable…
If we forget two words, we have to guess up to 1626^2 times (2’643’876). Ok, now its getting harder but still manageable for computers.
What about 4 words missing? A short test by the Reddit User /u/JollyMort concluded, that it would take up to 201 years for a computer to guess the full mnemonic seed with 4 missing words.
But what if we dont know any of our seed words? Well, then we have to guess up to 1626^25 times to recreate our mnemonic seed. That number is so high, that nowadays computers can not crack this in reasonable time and by reasonable time, i mean in the next few thousand trillion years (remember, we humans only existed for about 200k years so far)…beside the guessing of the seed, the computer would have to fully synchronize with the created wallet to check if there is actual balance on it, which would slow down things quite a bit.
So all in all, its pretty much next to impossible to bruteforce your mnemonic seed with todays technology. Isnt this amazing?
I hope you enjoyed the explanation and learned something new today:)