BIP-32 — BIP-32 is the Bitcoin Improvement Proposal that defines hierarchical deterministic (HD) wallets — a tree of keys derived from a single master seed, so a wallet can generate unlimited addresses without storing each one.
Given a master seed, BIP-32 derives child keys via HMAC-SHA512 over the parent key and an index. The result is a deterministic tree: from one seed you can recreate every key.
BIP-44 standardises the path layout: m / purpose' / coin_type' / account' / change / address_index. Coin types are registered (0' = BTC, 60' = ETH, 501' = SOL, etc.), which lets the same seed manage every supported chain.
Kronos uses BIP-32 (via @scure/bip32) with BIP-44 paths to derive per-coin private keys from the user's on-device BIP-39 seed. Each supported chain — Bitcoin, Ethereum, Solana, etc. — gets its own derivation path; one seed covers all 30+ coins.
They reduce backup complexity (one seed instead of many keys), enable unlimited address generation, and support cross-chain wallets.