Cryptocurrency wallets use the BIP32 scheme which provides an even neater ability: from a root public key alone you can generate a series of children public key

Cryptocurrency wallets use the BIP32 scheme which provides an even neater ability: from a root public key alone you can generate a series of children public keys, no private keys are involved in the calculation. (And whoever posses the root private key can generate the corresponding series of children private keys.) The technical aspects are described in https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#Specification_Key_derivation https://github.com/bitcoin/bips/blob/master/bip-0032.mediawi... But that's overkill given the simpler requirements of Find My. Each device stores the private key so they don't need something with the feature set of BIP32.