<p>A private key is the only way to assure everybody else you and only signed a specific transaction saying 'give X of my coins to Y'.</p>

<p>If you publish your private key, anybody can sign transactions like that and your money can be stolen. You should keep your private key private.</p>

CC BY-SA 3.0
2018-02-16T14:05:22.910Z
2018-02-16T14:05:22.910Z
Osias Jota
<p>Standard Bitcoin addresses encode a user's public key. When someone sends bitcoins to such a "pay-to-public-key-hash" address, they sign them over to the owner of the specific public key. The public key hereby is part of a unique key pair. The public  key (as in public knowledge) can be shared freely, while the private key should be kept secret.</p>

<p>When the new owner of the funds wants to spend them, they have to prove their ownership. To that end, they provide a signature that corresponds to the public key that the funds were assigned to. This signature can only be produced with the knowledge of the corresponding private key, but can then be checked by everyone that knows the public key.</p>

<p>You therefore need the private key to prove your ownership in order to spend funds.</p>

CC BY-SA 3.0
2018-02-16T18:35:17.607Z
2018-02-16T18:35:17.607Z
Murch
<p>At the time when the new owner of the assets needs to spend them, they need to demonstrate their possession. That time they give a signature that belongs to the public key that the assets were assigned to. This signature can only be invented with the instruction of the corresponding private key, but can then be checked by everyone that knows the public key. You always need the private key for showing ownership of this assets in order to spend funds. </p>

CC BY-SA 3.0
2018-02-22T06:38:47.737Z
2018-02-22T06:38:47.737Z
rickeyroy
<p>technically speaking, the private key is used to sign a hash of a transaction. This signature process proves, that only the person with a private key belonging to its public key (from which the address could be derived) could sign this hash. As this is somewhat of a very generic question, I think it is a good idea to look up the principles of transaction processing in bitcoin in Andreas' book "Mastering Bitcoin". It is an amazing book that'll definitely get you started. It's freely <a href="http://chimera.labs.oreilly.com/books/1234000001802/index.html" rel="nofollow noreferrer">available online here</a> ...</p>

CC BY-SA 3.0
2018-02-16T16:39:23.457Z
2018-02-16T16:39:23.457Z
pebwindkraft
<p>Why do I need a private key to send someone my bitcoins? </p>

CC BY-SA 3.0
2018-02-16T18:59:18.133Z
Paradoxical, because without the key you cannot even call it "my bitcoins" :)
skang404
<blockchain><private-key>
Why do I need a private key to send some my bitcoins?
C'matic Qongqo
# Why do I need a private key to send some my bitcoins?

(Asked by: username_0 on 2018-02-16)

Why do I need a private key to send someone my bitcoins?

**Tags:** blockchain, private-key

> **Comments:**
> **username_1**: Paradoxical, because without the key you cannot even call it "my bitcoins" :)  

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## 4 answers

### Answer by username_2 on 2018-02-16. Score: 1

A private key is the only way to assure everybody else you and only signed a specific transaction saying 'give X of my coins to Y'.

If you publish your private key, anybody can sign transactions like that and your money can be stolen. You should keep your private key private.


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### Answer by username_3 on 2018-02-16. Score: 1

Standard Bitcoin addresses encode a user's public key. When someone sends bitcoins to such a "pay-to-public-key-hash" address, they sign them over to the owner of the specific public key. The public key hereby is part of a unique key pair. The public key (as in public knowledge) can be shared freely, while the private key should be kept secret.

When the new owner of the funds wants to spend them, they have to prove their ownership. To that end, they provide a signature that corresponds to the public key that the funds were assigned to. This signature can only be produced with the knowledge of the corresponding private key, but can then be checked by everyone that knows the public key.

You therefore need the private key to prove your ownership in order to spend funds.


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### Answer by username_4 on 2018-02-22. Score: 0

At the time when the new owner of the assets needs to spend them, they need to demonstrate their possession. That time they give a signature that belongs to the public key that the assets were assigned to. This signature can only be invented with the instruction of the corresponding private key, but can then be checked by everyone that knows the public key. You always need the private key for showing ownership of this assets in order to spend funds.


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### Answer by username_5 on 2018-02-16. Score: 0

technically speaking, the private key is used to sign a hash of a transaction. This signature process proves, that only the person with a private key belonging to its public key (from which the address could be derived) could sign this hash. As this is somewhat of a very generic question, I think it is a good idea to look up the principles of transaction processing in bitcoin in Andreas' book "Mastering Bitcoin". It is an amazing book that'll definitely get you started. It's freely [available online here](http://chimera.labs.oreilly.com/books/1234000001802/index.html) ...


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