July 9, 2025

How secure is your mnemonic seed?

Diving into the security of Bitcoin wallets via entropy, checksums, and BIP39.

You already know your wallet’s 12 or 24 words represent a BIP39 mnemonic — but what’s actually going on under the hood?

I wrote a deep-dive to explore that question from first principles:
→ How secure is your Bitcoin wallet’s seed phrase?

It walks through how entropy is turned into a seed, how the checksum works, and how minor changes in input affect the final address. There’s also a visualizer so you can flip bits and see the downstream effect.

If you’ve ever wondered why BIP39 works the way it does — or how secure your seed really is — this should help make it click.

– Tom