Spreading wealth across places has been standard advice for a long time. With bitcoin it can be done with a few keys and some planning, no holding structures needed.
The idea: instead of one seed in one place, you use a multisig vault where, say, any 3 of 5 keys can sign. Then you spread the keys. One at home, one in a safe deposit box, one with a trusted person in another city, one in another country.
Lose two keys, or have two out of reach, and you can still move your funds. Someone who gets hold of one or two can't.
It's more work than a single hardware wallet in a drawer for sure, but you benefit from much better security! For people whose lives span several countries, which describes a lot of people in this region in particular, it's worth thinking about seriously.
PS: remember, in a multisig setup, the different keys enable you to sign transactions to move funds; they don’t individually “hold” a part of your assets, that’s why losing one or two in a 3-out-of-5 architecture doesn’t mean you’ve lost any of your funds.
The riskiest moment in self-custody is often the transfer.
Buy on an exchange. Copy an address. Paste it. Hope your clipboard hasn't been tampered with. Check the first and last characters. Wait. Repeat every month if you're stacking.
In the US, Casa members can buy bitcoin directly in the app and send it to their vault in seconds, and ACH purchases now come with zero fees for transfers of $250 or more. For larger positions, our OTC desk handles execution.
Fewer apps, fewer copy-pastes, fewer moments where things can go wrong.
If you already own a hardware wallet, you're closer to multisig than you think.
A lot of people I speak with assume that moving to Casa means starting from zero. It’s not true!
On the Standard plan you bring your own device, and it becomes one of the keys of your vault. Your phone becomes the second one for example, and Casa holds a third for recovery. Here you go, a more secure 3-key vault 😊
Same hardware you already trust, but no longer a single point of failure. If that one device breaks, gets lost or turns out to have a flaw (as seen recently in multiple situations…), your bitcoin doesn't go with it.
And if you'd rather not do it alone, our team can walk you through the setup live.
People often assume self-custody is a bitcoin-only topic. More and more of the conversations I have, especially in this region, are about stablecoins.
Businesses paid in USDT. Families holding USDC as their dollar savings. Freelancers invoicing clients abroad.
The risks are the same as with bitcoin: an exchange account can be frozen, a single wallet can be drained, a seed phrase can be lost. And the answer is the same too.
Casa vaults secure BTC, ETH, USDT and USDC with the same multi-key setup, recovery and inheritance. Same app, same advisors.
A caveat tough: stablecoin issuers can freeze tokens at their end. Multisig protects you from losing your keys, not from the issuer.
When someone calls Casa, it's sometimes because things are not going well. A lost phone. A hardware wallet that won't turn on. A message that looks like it's from us but isn't. And, occasionally, something more serious.
That's why our advisors go through a six-month training programme before they support members on their own.
In a world where more and more services get automated, I'm glad this part of Casa stays very human. Software protects the keys. Our people help you make good decisions when you're stressed.
Shout-out to the team 🤝
Important reminder. Your setup is what matters, solutions have been built to protect you from specific risks.
Make the right choice. Happy to help if you want to choose @CasaHODL
Compromised crypto hardware is nothing new. We've seen them as far back as 2018 with counterfeit Trezor One devices being sold.
@CasaHODL's security model has protected our clients against supply chain attacks since inception:
docs.casa.io/wealth-security…
We are an official Ledger reseller and source the Ledgers that we provide to our clients directly from Ledger.
They are then stored in an access controlled location until being sent to Casa clients with the original Ledger packaging intact.
The Ledger supply chain incident is another reason why we designed Casa to integrate with many different hardware signers and vendors - to protect against vulnerabilities from any one device.
Quick self-custody check for your Monday. Especially relevant after what started over the weekend with Ledger… (still developing)
Is there a photo of your seed phrase on your phone? A note in your email drafts? A screenshot sitting in a cloud backup?
If yes, your cold wallet isn't that cold anymore. The security of the whole setup is now the security of your iCloud or Google password.
Same problem, in a different way, if the only copy is one piece of paper in one drawer. One fire, one flood, one house move: gone.
The words need to be offline, and they shouldn't all sit in one place. That's hard to do well with a single seed, and it's one of the reasons multisig exists: several keys, in several places, none of them enough on its own (this could be the difference between losing everything from your hijacked single wallet and being safe, back to my intro point).
Something I've noticed doing both sales and coaching: the best conversations in both are the ones where I talk the least.
On a good discovery call, the prospect tells me what actually worries them, not what they think I want to hear. In a good coaching session, the client hears themselves say something they hadn't quite put into words before.
In both cases, the work on my side is mostly this: ask a real question, then stay quiet a little longer than feels comfortable.
It took me years in management to learn it. Leading large teams, I was usually the one expected to speak first and have the answer. Coaching taught me that the most useful thing I can bring is space.
Still practising. Some days better than others.
Multi-vendor multisig means you don't have to rely on just one hardware device manufacturer, so your bitcoin stays protected even if one of your devices has a security issue
You can get started with hardware you already own and your mobile phone in less than 5 minutes.
When Coldcard’s flaw surfaced in August, Casa multisig vaults with Coldcard wallets were unaffected.
blog.casa.io/an-introduction…
More resources on multi-vendor multisig in the comments.
Benjamin “Bader” Ampen retweeted
Two-factor authentication requires every factor. Lose your 2FA or password and you could be locked out alongside any attackers.
Multisig vaults run on a threshold. In a 3-key vault, any two keys can sign, and the third is your margin for error.
Phish one key or destroy one, and you can still move your bitcoin.
Full primer on threshold security:
blog.casa.io/an-introduction…
Benjamin “Bader” Ampen retweeted
Replying to @KurnelKertz @CasaHODL
Casa is an authorized reseller for hardware; we receive bulk shipments directly from manufacturers and store them securely before reshipping. But it's also optional to even use hardware provided through us - you're welcome to source your own hardware directly from manufacturers.
Benjamin “Bader” Ampen retweeted
Multi-vendor multisig protects you against supply chain attacks. @CasaHODL users unaffected.
xitter.cf/Ledger_Support/status/…
Ledger is investigating reports of loss of funds from users in South East Asia who purchased products from a reseller named CryptoBillis. As a precaution, and pending the results of our investigation, we have asked CryptoBilis to pause all sales and shipments of Ledger devices. We recommend Ledger users who purchased from this reseller in the last 90 days to not initiate set up if you have not done so yet. If you have set up your Ledger device, consider moving assets to a new Ledger signer (with new seed). We will continue to inform customers of updates as the investigation progresses.
Reach out to Ledger customer support through official channels with any questions: support.ledger.com/
Here we go again …
⚠️ Beware if you use a Ledger hardware wallet, especially if you bought one recently.
Based on information so far, it seems to be localized to a supply chain attack with one vendor. A small number of people probably bought fake (or tampered) Ledgers.
Ledger is one of the most secure and oldest hardware wallets in the industry. Stood the test of time. But these things happen.
I expect and know all BNB ecosystem players (and all industry) to help trace and recover the funds.
Buying a bitcoin ETF and holding bitcoin are two fundamentally different things. I don’t think we can (and should) compare them head to head.
Both can make sense in my opinion.
An ETF gives you price exposure in the brokerage account you already have. Easy, familiar, regulated.
What it doesn't give you is the asset itself: you can't move it, you can't take it with you, and you rely on a chain of custodians, brokers and rules you don't control.
Self-custody is the opposite trade-off: full ownership, full control, and full responsibility.
I don't think everyone should self-custody everything. But I do think everyone who owns bitcoin should make that choice knowingly, and not by default because the ETF button was easier to click.
What do you think on this topic?
Benjamin “Bader” Ampen retweeted
The best thing you can do to protect your Bitcoin against this is to make sure that you are not reusing addresses that you have already spent from.
When you spend from a Bitcoin wallet on-chain, it reveals the public key(s) for that wallet. If the public key becomes known, then it could theoretically be reverse-engineered to crack the private key (in this hypothetical future where ECDSA is cracked). However when you deposit into a fresh address, it’s quite hard to correlate it to any specific wallet.
If you are using Casa, we manage this for you. When you send BTC from Casa, the change automatically goes to a new address in your wallet. Anytime you receive into Casa, we give you a fresh address without any deposits in it.
It's hard to say how likely it is that the core wallet cryptography underpinning Bitcoin and other cryptocurrencies could be cracked by non-quantum means; but you certainly can't discount the fact that OpenAI and others are solving a ridiculous amount of long-standing mathematics problems right now.
I think this risk results in further necessary investigation (and transparency?) around how some of the largest exchanges and custodians are managing address reuse. Unfortunately address reuse has historically been a best practice at some companies for managing wallets, because it helps avoid fat-fingering and other human mistakes. It’s possible the cryptographic breakthrough risk will start to outweigh the human mistake risk.
I also think this is another great argument for why the distribution of risk via self custody benefits the Bitcoin network as a whole. We saw with the Coldcard exploit that it took time to crack many individual wallets, giving people time to move assets to safety. The more centralized the custody of Bitcoin is, the more risk there is from a vulnerability in wallet cryptography.
Today I call upon the blockchain industry to calmly begin planning for "bunker mode". My personal recommendation is to set in motion a controlled mass migration of assets to fresh addresses, i.e. addresses whose pubkeys remain hidden behind a hash.
Holders, starting with large and sophisticated ones, should consider moving the bulk of their funds to addresses that have never signed a transaction. And when they do sign one, they should also move remaining funds to a new address (possibly generated from the same seed phrase).
Don't rush. While I believe there is cause for action a rushed migration would do more harm than good. Don't panic either. Moving assets to protected addresses is a simple, preventative step which does not require new cryptography or new wallets.
IMO it is now reasonable to brace for the possibility that ECDSA breaks before qday, in the worst case in months not years. By "break" I mean fast private key recovery (e.g. in one week) on available hardware (e.g. a large GPU cluster).
Recent days have been humbling for human mathematical intuition. Long-held, unquestioned hypotheses have fallen. This includes the n log(n) bound for integer multiplication and the 3SUM conjecture. In hindsight, May's unexpected disproof of the Erdős unit distance conjecture was our warning shot.
Yesterday's OpenAI drop made it clear that mathematical superintelligence is upon us. They say there are weeks where decades happen. We are about to live through weeks where centuries of mathematical progress happen. Could our magic 64-byte ECDSA signatures be too good to be true? Was it just security through obscurity all this time?
Elliptic curves feel especially vulnerable to superintelligence. Curves carry rich structure, with room for fancy tricks like Schoof, Frobenius, pairings. (By contrast, hashes are designed to minimise algebraic structure.)
Separately, as Ewin Tang can attest, an efficient quantum algorithm sometimes foreshadows an efficient classical one. We should be open to the possibility of a classical counterpart to Shor that breaks elliptic curves and RSA at once.
Also noteworthy is the striking under-representation of cryptographic breakthroughs among the 722 mathematical results OpenAI published. I've witnessed first-hand the US government censoring academic quantum cryptanalysis results. Backroom interventionism is my base case.
I urge large, sophisticated actors to lead by example. Project11's "risq list" (bitcoin-risq-list.projecteleven[.]com) is a great tracker of exposed BTC pubkeys. Binance, Bitbank, Robinhood, Bitfinex, and Tether have an opportunity to harden their cold storage. Next month I'll address institutions in London in a live Q&A (forum.ethereuminstitutional[.]org/london-2026).
Again, please do not rush. Wallets holding under 50 BTC enjoy partial cover from "Satoshi's shield", i.e. his 20K exposed addresses that hold 50 BTC each. Load-bearing signers like oracles and L2 security councils should consider rotating ECDSA pubkeys with every signed message and/or multi-signing with a hash-based schemes like SPHINCS.
Exiting bunker mode safely will require post-AI cryptography. My inclination is to go all-in on hash-based cryptography and avoid structured mathematical assumptions entirely, whether from curves, lattices, or isogenies. A single battle-tested hash (e.g. from the SHA or BLAKE families) yields plausible post-AI security.
The Ethereum roadmap on strawmap[.]org fully embraces hash-based cryptography with end-to-end formal verification as a response to the quantum threat. Those timelines must now be revisited and accelerated in light of mathematical superintelligence. I'll be pushing for maximum defensive acceleration.
There's a big pink button in the Casa app. I hope most of our members never press it.
It's called « Emergency Lockdown ».
If you're ever under physical threat, or travelling somewhere you don't feel safe, one tap logs you out and freezes all activity on your account for 72 hours.
The part people are surprised by: on the Standard plan, nobody can undo it. Not you, not someone holding your phone, not our team. It unlocks by itself after 72 hours. (Premium members unlock with video verification instead.)
Why 72? Because it's rare that victims are held for more than 48 hours, so there's a buffer on top.
A feature designed for the worst day of someone's life. I sleep better knowing our members have it 🔐
« What happens to my bitcoin if Casa disappears tomorrow? »
It's a fair question, and honestly I'd be worried if people didn't ask it. Most of us have watched a custodian collapse and take client funds with it 😔
The answer: your vault doesn't depend on @CasaHODL existing.
Because you hold the majority of the keys, you can always use open-source software to access and move your funds without us. We call it sovereign recovery, and it comes with every plan.
We don't want to be a company you can't leave. We want to be the one you choose to stay with, because the service and we offer are worth it.
That's the whole idea of self-custody 🔐✊























