Here's how it works the magic behind mnemonic wallets, per BIP39 & BIP32:


Words Entropy

(12 words = 128 bits, 24 words = 256 bits)


Then comes:


PBKDF2-HMAC-SHA512(

    password = mnemonic,

    salt = "mnemonic" + passphrase,

    iterations = 2048

)


This yields a 512-bit seed —

Split cleanly in half:


Left 256 bits Master Private Key

Right 256 bits Chain Code


The private key is only the left half.

The chain code enables deterministic child key derivation but remains silent, never exposed.