BIP39 is a standard that defines how to generate a mnemonic phrase, which is a group of words that can be used to represent a large, randomly generated number. This mnemonic phrase can then be used to generate a binary seed, which is a representation of the same number in binary form. The binary seed can be used to generate a hierarchical deterministic (HD) wallet, which is a type of Bitcoin wallet that can be used to generate an unlimited number of unique addresses from a single seed.
NIP-06 is a proposal for the Nostr protocol that suggests using BIP39 and BIP32 to generate keys for use with the protocol. Specifically, it proposes using BIP39 to generate the mnemonic phrase, and BIP32 to generate the hierarchical deterministic wallet and derive the keys for use with Nostr. In the case of NIP-06, the derivation path specified is m/44’/1237’/0’/0/0, which is the path recommended for use with Nostr according to SLIP44. This path is considered the default for basic single-key clients, but other types of clients may use different derivation paths for their own purposes.
Using BIP39 and BIP32 allows for a more secure and user-friendly key generation process for Nostr users. By using a mnemonic phrase instead of a random string of characters, users can more easily remember and protect their keys. Additionally, the hierarchical deterministic wallet allows for the generation of multiple keys from a single seed, providing more flexibility and security for users. If you combine NIP-26‘s ability to delegate keys you could use your main key to create smaller keys that get delegated the authority for your account for a set period of time.
Overall, NIP-06 is an important proposal for the Nostr protocol as it outlines a standard for key generation that is secure, user-friendly, and flexible. By using BIP39 and BIP32, Nostr users can have confidence that their keys are being generated in a secure and reliable manner.