<p>There really isn't a "positive" or "negative" for private keys. Private keys are unsigned integers, so they're basically all "positive". Your "negative" numbers are not actually negative, they're the modular additive inverse of the "positive" private key.</p>

<p>Since private keys are really unsigned integers, you can't glean any information about signed-ness from the public key because there are no signs to even look at. Every private key is the "negative" of another private key, so a private key is both "positive" and "negative". Every private key has an additive inverse.</p>

<p>However, given two public keys, you can determine whether their private keys are additive inverses of each other by checking whether the X coordinates are the same. If so, one should have a Y coordinate that is odd, and the other have a Y coordinate that is even. This only tells you that their private keys are additive inverses of each other. But you won't know which is the lower number or what one of them is (unless you have the private key for one of them).</p>

CC BY-SA 4.0
2021-09-13T22:00:18.467Z
Can I get the positive private key from the negative key?
Mehran Jalili
CC BY-SA 4.0
2021-09-14T09:57:00.233Z
Please help. I need to do this kotlin or java
Mehran Jalili
CC BY-SA 4.0
2023-05-22T03:13:28.530Z
you can invert the private key within the field, yes
Erik Aronesty
CC BY-SA 4.0
2020-01-29T17:41:06.803Z
2020-01-29T17:41:06.803Z
Ava Chow
<p>Private key is a number. Is the question positive or negative? Is it possible to know a positive private key or negative if you only know the public key?</p>

<p>For instance:</p>

<p>Positive private key: 2</p>

<p>public key: </p>

<pre><code>04C6047F9441ED7D6D3045406E95C07CD85C778E4B8CEF3CA7ABAC09B95C709EE51AE168FEA63DC339A3C58419466CEAEEF7F632653266D0E1236431A950CFE52A
</code></pre>

<p>Negative Private Key: 
<code>FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD036413F</code></p>

<p>public key: </p>

<pre><code>04C6047F9441ED7D6D3045406E95C07CD85C778E4B8CEF3CA7ABAC09B95C709EE5E51E970159C23CC65C3A7BE6B99315110809CD9ACD992F1EDC9BCE55AF301705
</code></pre>

<p>Now I will write two public keys to "<code>3</code>" and "<code>FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD036413E</code>":</p>

<pre><code>04F9308A019258C31049344F85F89D5229B531C845836F99B08601F113BCE036F9388F7B0F632DE8140FE337E62A37F3566500A99934C2231B6CB9FD7584B8E672

04F9308A019258C31049344F85F89D5229B531C845836F99B08601F113BCE036F9C77084F09CD217EBF01CC819D5C80CA99AFF5666CB3DDCE4934602897B4715BD
</code></pre>

<p>How to determine which is a positive and which is a negative private key to these two public keys?</p>

<private-key><public-key><cryptography><secp256k1>
Positive or negative private key of a bitcoin wallet?
Rozwrcd
# Positive or negative private key of a bitcoin wallet?

(Asked by: username_0 on 2020-01-29)

Private key is a number. Is the question positive or negative? Is it possible to know a positive private key or negative if you only know the public key?

For instance:

Positive private key: 2

public key:

```
04C6047F9441ED7D6D3045406E95C07CD85C778E4B8CEF3CA7ABAC09B95C709EE51AE168FEA63DC339A3C58419466CEAEEF7F632653266D0E1236431A950CFE52A

```

Negative Private Key:
`FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD036413F`

public key:

```
04C6047F9441ED7D6D3045406E95C07CD85C778E4B8CEF3CA7ABAC09B95C709EE5E51E970159C23CC65C3A7BE6B99315110809CD9ACD992F1EDC9BCE55AF301705

```

Now I will write two public keys to "`3`" and "`FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD036413E`":

```
04F9308A019258C31049344F85F89D5229B531C845836F99B08601F113BCE036F9388F7B0F632DE8140FE337E62A37F3566500A99934C2231B6CB9FD7584B8E672

04F9308A019258C31049344F85F89D5229B531C845836F99B08601F113BCE036F9C77084F09CD217EBF01CC819D5C80CA99AFF5666CB3DDCE4934602897B4715BD

```

How to determine which is a positive and which is a negative private key to these two public keys?

**Tags:** private-key, public-key, cryptography, secp256k1


---

## 1 answers

### Answer by username_1 on 2020-01-29. Score: 4

There really isn't a "positive" or "negative" for private keys. Private keys are unsigned integers, so they're basically all "positive". Your "negative" numbers are not actually negative, they're the modular additive inverse of the "positive" private key.

Since private keys are really unsigned integers, you can't glean any information about signed-ness from the public key because there are no signs to even look at. Every private key is the "negative" of another private key, so a private key is both "positive" and "negative". Every private key has an additive inverse.

However, given two public keys, you can determine whether their private keys are additive inverses of each other by checking whether the X coordinates are the same. If so, one should have a Y coordinate that is odd, and the other have a Y coordinate that is even. This only tells you that their private keys are additive inverses of each other. But you won't know which is the lower number or what one of them is (unless you have the private key for one of them).

> **Comments:**
> **username_2**: Can I get the positive private key from the negative key?  
> **username_2**: Please help. I need to do this kotlin or java  
> **username_3**: you can invert the private key within the field, yes  

---

