Why Hot and Cold Wallets Must Never Share a Seed
Sharing a BIP39 seed across hot and cold wallets destroys physical isolation. Learn why separate seeds and watch-only setups are required.
PDF document · Published · Updated
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Contents
- The Irreversible Security Downgrade
- Why Spending Wallets Require Independent Seeds
- Funding Hot Wallets Without Exposing Cold Seeds
- BIP39 Passphrases as a Substitute for a Second Seed
- FAQ
- Sources
- Example sequences from the BIP39 wordlist
- Reading a BIP39 phrase
- See also
- Keywords:
- BIP39 seed phrase · cold storage · hot wallet · air gap · watch-only wallet
Guides on the same subject
- Hot Wallet vs Cold Wallet: Differences and When to Use Each
A hot wallet keeps its keys on an online device; a cold wallet keeps them offline. Speed, cost, risks and backups compared, and how to split funds between them.
- How to Store Crypto Safely: A Hot, Cold and Backup Plan
A practical plan for storing crypto: a small hot wallet for spending, cold storage for savings, separate backups and safe transfers between them.
- Cold Sharding: Splitting a Private Key Into Offline Shamir Shares
Cold sharding splits a key or seed into offline Shamir shares, such as any 3 of 5, so one share reveals nothing. How it works, its risks and multisig compared.
One of the documents in the Seed Phrase PDF Archive, listed on archive page 7.