Questions
Frequently asked questions
Why will there only ever be 21 million bitcoin?
The block subsidy started at 50 BTC and halves every 210,000 blocks (Bitcoin Core GetBlockSubsidy, validation.cpp; interval set in chainparams.cpp), a geometric series that sums to about 21 million. Every full node enforces this and rejects any block that pays its miner more than the subsidy plus fees, so changing it would need nearly everyone to voluntarily run different software (white paper, sections 5-6). Because rewards are whole satoshis and each halving rounds down, the true maximum is 20,999,999.9769 BTC, with the last subsidy paid around 2140. Go deeper: supply schedule · course module: Issuance and the halving.
What is bitcoin self-custody?
Holding the private keys to your bitcoin yourself, usually with a hardware wallet and a seed phrase backup, instead of leaving coins with an exchange.
Is it safe to keep bitcoin on an exchange?
It means trusting the exchange to stay solvent, secure and willing to process withdrawals. Mt. Gox's 2014 collapse is the classic example of what can go wrong. Self-custody removes that counterparty but makes you responsible for backups.
Which hardware wallet should I buy?
See our dated verdicts on the Security Status page. As of October 15, 2026 we recommend BitBox02, Blockstream Jade and Trezor Safe models on current firmware, COLDCARD for advanced users with new seeds only, and Ledger only if bought from ledger.com with Recover off.
Can I store my seed phrase in a password manager or take a photo of it?
No. Never photograph, screenshot, type or cloud-store your seed. Write it by hand, move it to metal, and keep it offline.
Does a firmware update fix a weak seed?
No. Updates fix the device, not seeds already generated. In the 2026 COLDCARD incident, affected users had to create new seeds on fixed firmware and move funds.
What is a passphrase (25th word)?
An optional extra secret that creates a different wallet from the same seed. It protects against someone who finds only the seed, but if you lose it the funds are unrecoverable, so back it up separately.
Should I use multisig?
For larger balances, a 2-of-3 multisig across different vendors and locations removes single points of failure. Learn single-sig first, and always back up the wallet descriptor.
Will Cold Hard Custody ever contact me or offer a call?
No. We do not offer calls, never ask for seed words, and never send firmware. Anyone claiming to be us and asking for these is a scammer.
Is any of this financial advice?
No. Everything here is educational. Do your own research and consult qualified professionals for legal, tax or estate questions.