<blockquote>
  <p>Is it possible to decode the private key from a signed input?</p>
</blockquote>

<p>No. Signatures and public keys are meant to be public. In typical use, using a correct implementation of the signing code, it is currently not possible to determine the private key for a signature and pubkey pair.</p>

<p>Signed inputs are not encrypted or obfuscated in any way, so when you broadcast your transaction, everything in the input, including the signature, will be publicly available for anyone to see.</p>

<hr>

<p>There are some cases where it is possible to determine the private key for a signature and pubkey pair. However these all involve faulty implementations of the signing code. They usually revolve around the use of bad randomness and otherwise failing to produce a random enough number. For the most part though, these failures are rare.</p>

CC BY-SA 4.0
2020-05-21T02:57:32.103Z
2020-05-21T02:57:32.103Z
Ava Chow
<p>Is it possible to decode the private key from a signed input?</p>

<p>For example:</p>

<hr>

<p>From this signed input hex...</p>

<pre><code>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
</code></pre>

<hr>

<p>Can I get this private key?</p>

<pre><code>cQ4JFq6BKwgvgqQcQK1d1ZNkpjmaDbmf3NJ99zYb9ESEnaPQwy3s
</code></pre>

<security><utxo><transaction-input>
Is sharing a signed input safe?
Michael
# Is sharing a signed input safe?

(Asked by: username_0 on 2020-05-21)

Is it possible to decode the private key from a signed input?

For example:

---

From this signed input hex...

```
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

```

---

Can I get this private key?

```
cQ4JFq6BKwgvgqQcQK1d1ZNkpjmaDbmf3NJ99zYb9ESEnaPQwy3s

```

**Tags:** security, utxo, transaction-input


---

## 1 answers

### Answer by username_1 on 2020-05-21. Score: 4 | Accepted answer

> Is it possible to decode the private key from a signed input?

No. Signatures and public keys are meant to be public. In typical use, using a correct implementation of the signing code, it is currently not possible to determine the private key for a signature and pubkey pair.

Signed inputs are not encrypted or obfuscated in any way, so when you broadcast your transaction, everything in the input, including the signature, will be publicly available for anyone to see.

---

There are some cases where it is possible to determine the private key for a signature and pubkey pair. However these all involve faulty implementations of the signing code. They usually revolve around the use of bad randomness and otherwise failing to produce a random enough number. For the most part though, these failures are rare.


---

