# FAQ

## Bip32 key derivation

* *Why don't you use standard Key derivation function PBKDF2?*

PBKDF2 (Password-Based Key Derivation Function 2) is designed for password inputs. We don't input password, but a long, random number. Even more importantly, it does not offer derivation of public/private keypairs. Bip32 does.\ <br>

* *Bip32 is used in deterministic (bitcoin) wallets. How does your scheme relate to that?*

Key derivation process is the same, usage of key-pair is different;

| bip32              | bitcoin deterministic wallet                                                     | ZeroPass Backup tier                                                                                                                      |
| ------------------ | -------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| Master Private Key | Used to transfer/reconstruct whole wallet within different services.             | Gets split/distributed and then erased. It can be put together if you lock yourself out (recovery procedure).                             |
| Master Public Key  | Used to generate (child) public bitcoin addresses without exposing private keys. | Used to encrypt all your passwords (with his child keys) that can be decrypted only with (at this point already erased) MasterPrivateKey. |

We can then safely sync MasterPublicKey between devices. Even if it gets leaked... it's Public key, it can not expose anything.