Luckily, in 2012 the developer Pieter Wuille made the BIP32 specification at the base from the hierarchical deterministic wallets. Together with it, Pieter made a mathematical function to make a master key from which to derive all other keys in a very deterministic way. A straightforward backup program for bitcoin https://www.anobii.com/en/01d109953642f9cd99/profile/activity