The good thing is, in 2012 the developer Pieter Wuille established the BIP32 specification at The bottom in the hierarchical deterministic wallets. Jointly with it, Pieter made a mathematical perform to create a master vital from which to derive all other keys inside a deterministic way. This post explains BIP39, https://socialrus.com/story18674787/not-known-factual-statements-about-bip39-explained