<p>As @Prayank mentioned before: Nothing. As <a href="https://www.cs.cmu.edu/%7Erdriley/487/papers/Thompson_1984_ReflectionsonTrustingTrust.pdf" rel="nofollow noreferrer">Ken Thompson</a> said: &quot;you can't trust code that you did not totally create yourself&quot;.</p>
<p>If you are paranoid, it's better that you use <a href="https://en.bitcoin.it/wiki/Cold_storage" rel="nofollow noreferrer">cold wallets</a> and make them air-gap.</p>

CC BY-SA 4.0
2020-10-15T13:12:25.467Z
2020-10-16T08:53:34.667Z
2020-10-16T08:53:34.667Z
Hypatia
<blockquote>
<p>Wallets contain your private keys and they obviously have to use them to be able to send coin.</p>
</blockquote>
<p>That is indeed a very valid concern; you good sir have exercised thinking well.</p>
<p>Others have thought the same, and created <strong>hardware wallets</strong> to tackle exactly this threat!</p>
<p>Those are basically USB dongles with a button — which you have to <em>physically press</em> before it signs any transaction. So, this:</p>
<blockquote>
<p>stealing bitcoin from a user in the background without the user's knowledge</p>
</blockquote>
<p>does not work anymore — even when your green shiny well-known well-reviewed Open Source wallet software has been discreetly infected (for example, to show you one destination address, but substitute another when sending funds).</p>
<p>Crucially, hardware wallets are designed to hold private keys within, and are supposed to never share them with the host computer / wallet program. Spending request in — signed transaction out. This also protects your funds. For another example, you can now be OK with having to use a public computer with a crappy OS on it.</p>
<p>Maybe check out <a href="https://bitcoin.org/en/wallets/hardware/" rel="nofollow noreferrer">https://bitcoin.org/en/wallets/hardware/</a> — I'm sure you'll manage to do your own research from there.</p>
<hr />
<p>Oh, and don't be fooled: just because it's a secure™ hardware chip — does not mean it can't be malicious in exactly the same way. Transparency requirements (e.g. Open Source firmware, bug bounty program, etc) still apply.</p>

CC BY-SA 4.0
2020-10-15T17:54:18.743Z
2020-10-15T17:54:18.743Z
ulidtko
<p>I'm not particularly knowledgeable on the topic of cryptocurrencies so it's possible that I've missed something obvious, but I still wonder what it is that stops a wallet from stealing from you. Wallets contain your private keys and they obviously have to use them to be able to send coin. So what stops a given wallet from stealing bitcoin from a user in the background without the user's knowledge?</p>

<wallet><wallet-security><malware>
What stops a wallet from stealing bitcoins?
Generic
# What stops a wallet from stealing bitcoins?

(Asked by: username_0 on 2020-10-15)

I'm not particularly knowledgeable on the topic of cryptocurrencies so it's possible that I've missed something obvious, but I still wonder what it is that stops a wallet from stealing from you. Wallets contain your private keys and they obviously have to use them to be able to send coin. So what stops a given wallet from stealing bitcoin from a user in the background without the user's knowledge?

**Tags:** wallet, wallet-security, malware


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## 2 answers

### Answer by username_1 on 2020-10-15. Score: 5

As @Prayank mentioned before: Nothing. As [Ken Thompson](https://www.cs.cmu.edu/%7Erdriley/487/papers/Thompson_1984_ReflectionsonTrustingTrust.pdf) said: "you can't trust code that you did not totally create yourself".

If you are paranoid, it's better that you use [cold wallets](https://en.bitcoin.it/wiki/Cold_storage) and make them air-gap.


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### Answer by username_2 on 2020-10-15. Score: 3

> Wallets contain your private keys and they obviously have to use them to be able to send coin.

That is indeed a very valid concern; you good sir have exercised thinking well.

Others have thought the same, and created **hardware wallets** to tackle exactly this threat!

Those are basically USB dongles with a button — which you have to *physically press* before it signs any transaction. So, this:

> stealing bitcoin from a user in the background without the user's knowledge

does not work anymore — even when your green shiny well-known well-reviewed Open Source wallet software has been discreetly infected (for example, to show you one destination address, but substitute another when sending funds).

Crucially, hardware wallets are designed to hold private keys within, and are supposed to never share them with the host computer / wallet program. Spending request in — signed transaction out. This also protects your funds. For another example, you can now be OK with having to use a public computer with a crappy OS on it.

Maybe check out <https://bitcoin.org/en/wallets/hardware/> — I'm sure you'll manage to do your own research from there.

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Oh, and don't be fooled: just because it's a secure™ hardware chip — does not mean it can't be malicious in exactly the same way. Transparency requirements (e.g. Open Source firmware, bug bounty program, etc) still apply.


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