Smart Keys are built by combining the best of the BIP32, BIP39, BIP44, and SLIP44 standards. A single 256-bit "root" key can be used to derive any coin that supports these standards. In addition, Smart Keys enable multiple account types spanning individual, joint and custodial - all from the root key.
How is my Smart Key created?
When you first create your wallet, you will be instructed to shake your device to generate your Smart Key. This is done 4 times, each time generating 6 words and never displaying them all at once on the screen.
When creating your Smart Key, your device does not need to be connected to the internet. Your Smart Key is NOT linked to your Ethos account - it is up to you to save your Smart Key somewhere safe. This is for your protection, ensuring that you, and you alone, can restore your wallet if needed.
Adhering to the BIP39 standard, your Smart Key will be a 24-word phrase that is randomly generated from a list of 2048 words. We are using multiple sources of entropy (random data) to generate Smart Keys- one of which is the accelerometer data! These help us ensure the Smart Key that is generated is truly random.
Can someone else guess or generate my Smart Key?
The probability of this is astronomically low. If the words selected for our 24-word phrase are chosen from a list of 2048 words, there are 2048^24 combinations. This can also be written as 2.96*10^79, or 29,642,774,844,752,946,028,434,172,162,224,104,410,437,116,074,403,984,394,101,141,506,025,761,187,823,616, combinations! That's more than 1 billion keys for every atom on Earth.