<p>closest I can come up with are these:</p>

<p><a href="http://coinig.com/" rel="nofollow noreferrer">http://coinig.com/</a></p>

<p><a href="http://gobittest.appspot.com/Address" rel="nofollow noreferrer">http://gobittest.appspot.com/Address</a> </p>

<p><a href="https://www.bitaddress.org/bitaddress.org-v3.2.0-SHA256-ad4fd171c647772aa76d0ce828731b01ca586596275d43a94008766b758e8736.html" rel="nofollow noreferrer">https://www.bitaddress.org/bitaddress.org-v3.2.0-SHA256-ad4fd171c647772aa76d0ce828731b01ca586596275d43a94008766b758e8736.html</a> </p>

<p><a href="https://coinb.in/" rel="nofollow noreferrer">https://coinb.in/</a></p>

<p>not exactly ECDSA, but served me alot for Bitcoin undertsanding/testing.</p>

<blockquote>
  <p><strong>Security hint</strong>: you would never provide/use a private key to/from such a public website, unless you are really sure of what you are
  doing. Be extremly careful.</p>
</blockquote>

CC BY-SA 3.0
2017-05-16T01:05:29.617Z
The first link lets me verify a public key + message + signature combination. Do you know of some online site that will generate a signature given a private key and a message (just for playing around purposes of course -- your fair warning is very apt).
thanks_in_advance
CC BY-SA 3.0
2017-05-16T09:44:46.400Z
no, I don't know a webpage that provides this ... when I was playing with signatures, I used the command line: https://bitcoin.stackexchange.com/questions/46455/verifying-a-bitcoin-trx-on-the-unix-cmd-line-with-openssl
pebwindkraft
CC BY-SA 3.0
2017-05-15T23:14:42.370Z
2017-05-15T23:14:42.370Z
pebwindkraft
<p>Here is an ECC calculator for the Secp256k1 curve that I'm programming in Java.
<a href="https://github.com/MrMaxweII/Secp256k1-Calculator" rel="nofollow noreferrer">https://github.com/MrMaxweII/Secp256k1-Calculator</a></p>

CC BY-SA 4.0
2019-11-17T11:37:41.640Z
for build modern GUI swing you can use this [library](https://github.com/vincenzopalazzo/material-ui-swing)
vincenzopalazzo
CC BY-SA 4.0
2019-11-16T19:36:47.467Z
2019-11-16T19:36:47.467Z
MixMAx123
<p>Here are a few I'd recommend:</p>

<ul>
<li><a href="https://bitcore.io/playground/#/address" rel="noreferrer">https://bitcore.io/playground/#/address</a> (private key - public key)</li>
<li><a href="https://brainwalletx.github.io/#generator" rel="noreferrer">https://brainwalletx.github.io/#generator</a> (signing and verifying but bitcoin specific)</li>
</ul>

<p>Or play with <code>pybitcointools</code> at the command line (not online):</p>

<pre><code>$ git clone https://github.com/vbuterin/pybitcointools.git
$ cd pybitcointools
$ python
&gt;&gt;&gt; from bitcoin import *
&gt;&gt;&gt; sk = random_key()  # Generate a private key
&gt;&gt;&gt; vk = privtopub(sk) # Generate a public key
&gt;&gt;&gt; msg = 'hello world' # Create a simple message
&gt;&gt;&gt; sig = ecdsa_sign(msg, sk) # Sign the message using your private key
&gt;&gt;&gt; print sig
GxXGAt...2L/eJk=
&gt;&gt;&gt; print ecdsa_verify(msg, sig, vk) # Use sig and public key to verify
True
&gt;&gt;&gt; msg = 'hello mars' # Change the message
&gt;&gt;&gt; print ecdsa_verify(msg, sig, vk) # Changing the msg invalidates sig
False
</code></pre>

<p><a href="http://showterm.io/203b168061b0156c4d1dd" rel="noreferrer">http://showterm.io/203b168061b0156c4d1dd</a></p>

<p>HD Wallet stuff:</p>

<ul>
<li><a href="https://iancoleman.github.io/bip39/" rel="noreferrer">https://iancoleman.github.io/bip39/</a></li>
<li><a href="http://bip32.org/" rel="noreferrer">http://bip32.org/</a></li>
</ul>

<p>If you're looking to learn more about ECDSA suggest checking out: <a href="https://jeremykun.com/2014/02/08/introducing-elliptic-curves/" rel="noreferrer">https://jeremykun.com/2014/02/08/introducing-elliptic-curves/</a></p>

CC BY-SA 3.0
2017-05-22T05:28:46.573Z
Question: In the first link (bitcore.io), they provide a private-public key pair, and an 'Address'. I presume the 'Address' is the SHA-256 hash of the public key. But when I try to hash the public key on this site (http://www.fileformat.info/tool/hash.htm) I don't get the same SHA-256 hash. Could you help me understand what the 'Address' is in that case?
thanks_in_advance
CC BY-SA 3.0
2017-05-24T02:10:31.613Z
Address creation is a bit more complicated. It's really a series of steps as shown here: http://gobittest.appspot.com/Address. Though there are two types (compressed vs. uncompressed) and I believe you will get different addresses if you use the gobittest vs. bitcore.
Justin O'Brien
CC BY-SA 3.0
2017-05-24T02:18:36.483Z
Using this private key: 2b1f14de0bc7b8d71a6409749e9e88d6e227c6516943713ed08448343722ae85
Bitcore generates: 1JmAEL8KbzVXFc15KUb9YXjgTop321WiC6
Gobittest generates: 1JsnjS7t8JW5CDi1UMwp6BSG2rJ3Xm94BF
For more see: https://github.com/bitcoin-bootcamp/bitcoin-exercises/tree/master/addresses
$ python address.py --secret '2b1...e85'
Bitcoin Address (Compressed): 1JmAEL8KbzVXFc15KUb9YXjgTop321WiC6
$ python address.py --secret '2b1...e85' --u
Bitcoin Address (Uncompressed): 1JsnjS7t8JW5CDi1UMwp6BSG2rJ3Xm94BF
Justin O'Brien
CC BY-SA 3.0
2017-05-24T12:17:06.493Z
Interesting - good to know. I thought a bitcoin address was simply the hash of a public key. Turns out it's more complicated.
thanks_in_advance
CC BY-SA 3.0
2017-05-21T18:37:20.740Z
2017-05-21T18:37:20.740Z
Justin O'Brien
<p>I realize that this question may be borderline bannable because it's asking for suggestions on tools, but it will really help newbies. This online tool allowed me to play around with hashes and to really understand them at a deeper level: <a href="http://www.fileformat.info/tool/hash.htm" rel="noreferrer">http://www.fileformat.info/tool/hash.htm</a></p>

<p>I can't find a similar tool (that works) for ECDSA cryptography where I can play around with public and private keys, and do digital signatures on messages, and test signature verification.</p>

<p>I've found these 2 sites that claim to do this but didn't work for me:</p>

<ol>
<li><p><a href="http://dbis.rwth-aachen.de/~renzel/mobsos/lib/js/jsrsasign/sample-ecdsa.html" rel="noreferrer">http://dbis.rwth-aachen.de/~renzel/mobsos/lib/js/jsrsasign/sample-ecdsa.html</a></p></li>
<li><p><a href="http://extranet.cryptomathic.com/ecc/index" rel="noreferrer">http://extranet.cryptomathic.com/ecc/index</a></p></li>
</ol>

<p>Thoughts? Suggestions?</p>

<hr>

<p>UPDATE: Great suggestions below. Some tools I found:</p>

<p>for hashing:
<a href="http://www.fileformat.info/tool/hash.htm" rel="noreferrer">http://www.fileformat.info/tool/hash.htm</a></p>

<p>generating public private key pairs and decrypting ciphers:
<a href="https://8gwifi.org/rsafunctions.jsp" rel="noreferrer">https://8gwifi.org/rsafunctions.jsp</a></p>

<p>Generating EC public private key pairs and signing Verifying the Message 
<a href="https://8gwifi.org/ecsignverify.jsp" rel="noreferrer">https://8gwifi.org/ecsignverify.jsp</a></p>

<p>generating public private key pairs and testing signing:
<a href="https://kjur.github.io/jsrsasign/sample/sample-ecdsa.html" rel="noreferrer">https://kjur.github.io/jsrsasign/sample/sample-ecdsa.html</a></p>

CC BY-SA 4.0
2018-08-07T02:51:47.177Z
For generating EC Keys https://8gwifi.org/ecfunctions.jsp
anish
CC BY-SA 4.0
2023-05-16T10:30:33.217Z
HDwallet Generator https://8gwifi.org/hdwallet.jsp
anish
<ecdsa><message-signing><message-verification>
online tool to play around with ECDSA public keys, message signature verification?
thanks_in_advance
# online tool to play around with ECDSA public keys, message signature verification?

(Asked by: username_0 on 2017-05-15)

I realize that this question may be borderline bannable because it's asking for suggestions on tools, but it will really help newbies. This online tool allowed me to play around with hashes and to really understand them at a deeper level: <http://www.fileformat.info/tool/hash.htm>

I can't find a similar tool (that works) for ECDSA cryptography where I can play around with public and private keys, and do digital signatures on messages, and test signature verification.

I've found these 2 sites that claim to do this but didn't work for me:

1. <http://dbis.rwth-aachen.de/~renzel/mobsos/lib/js/jsrsasign/sample-ecdsa.html>
2. <http://extranet.cryptomathic.com/ecc/index>

Thoughts? Suggestions?

---

UPDATE: Great suggestions below. Some tools I found:

for hashing:
<http://www.fileformat.info/tool/hash.htm>

generating public private key pairs and decrypting ciphers:
<https://8gwifi.org/rsafunctions.jsp>

Generating EC public private key pairs and signing Verifying the Message
<https://8gwifi.org/ecsignverify.jsp>

generating public private key pairs and testing signing:
<https://kjur.github.io/jsrsasign/sample/sample-ecdsa.html>

**Tags:** ecdsa, message-signing, message-verification

> **Comments:**
> **username_1**: For generating EC Keys https://8gwifi.org/ecfunctions.jsp  
> **username_1**: HDwallet Generator https://8gwifi.org/hdwallet.jsp  

---

## 3 answers

### Answer by username_5 on 2017-05-21. Score: 5 | Accepted answer

Here are a few I'd recommend:

https://bitcore.io/playground/#/address (private key - public key)
https://brainwalletx.github.io/#generator (signing and verifying but bitcoin specific)

Or play with pybitcointools at the command line (not online):
$ git clone https://github.com/vbuterin/pybitcointools.git
$ cd pybitcointools
$ python
>>> from bitcoin import *
>>> sk = random_key()  # Generate a private key
>>> vk = privtopub(sk) # Generate a public key
>>> msg = 'hello world' # Create a simple message
>>> sig = ecdsa_sign(msg, sk) # Sign the message using your private key
>>> print sig
GxXGAt...2L/eJk=
>>> print ecdsa_verify(msg, sig, vk) # Use sig and public key to verify
True
>>> msg = 'hello mars' # Change the message
>>> print ecdsa_verify(msg, sig, vk) # Changing the msg invalidates sig
False

http://showterm.io/203b168061b0156c4d1dd
HD Wallet stuff:

https://iancoleman.github.io/bip39/
http://bip32.org/

If you're looking to learn more about ECDSA suggest checking out: https://jeremykun.com/2014/02/08/introducing-elliptic-curves/

> **Comments:**
> **username_0**: Question: In the first link (bitcore.io), they provide a private-public key pair, and an 'Address'. I presume the 'Address' is the SHA-256 hash of the public key. But when I try to hash the public key on this site (http://www.fileformat.info/tool/hash.htm) I don't get the same SHA-256 hash. Could you help me understand what the 'Address' is in that case?  
> **username_5**: Address creation is a bit more complicated. It's really a series of steps as shown here: http://gobittest.appspot.com/Address. Though there are two types (compressed vs. uncompressed) and I believe you will get different addresses if you use the gobittest vs. bitcore.  
> **username_5**: Using this private key: 2b1f14de0bc7b8d71a6409749e9e88d6e227c6516943713ed08448343722ae85 Bitcore generates: 1JmAEL8KbzVXFc15KUb9YXjgTop321WiC6 Gobittest generates: 1JsnjS7t8JW5CDi1UMwp6BSG2rJ3Xm94BF For more see: https://github.com/bitcoin-bootcamp/bitcoin-exercises/tree/master/addresses $ python address.py --secret '2b1...e85' Bitcoin Address (Compressed): 1JmAEL8KbzVXFc15KUb9YXjgTop321WiC6 $ python address.py --secret '2b1...e85' --u Bitcoin Address (Uncompressed): 1JsnjS7t8JW5CDi1UMwp6BSG2rJ3Xm94BF  
> **username_0**: Interesting - good to know. I thought a bitcoin address was simply the hash of a public key. Turns out it's more complicated.  

---

### Answer by username_2 on 2017-05-15. Score: 3

closest I can come up with are these:

<http://coinig.com/>

<http://gobittest.appspot.com/Address>

<https://www.bitaddress.org/bitaddress.org-v3.2.0-SHA256-ad4fd171c647772aa76d0ce828731b01ca586596275d43a94008766b758e8736.html>

<https://coinb.in/>

not exactly ECDSA, but served me alot for Bitcoin undertsanding/testing.

> **Security hint**: you would never provide/use a private key to/from such a public website, unless you are really sure of what you are
> doing. Be extremly careful.

> **Comments:**
> **username_0**: The first link lets me verify a public key + message + signature combination. Do you know of some online site that will generate a signature given a private key and a message (just for playing around purposes of course -- your fair warning is very apt).  
> **username_2**: no, I don't know a webpage that provides this ... when I was playing with signatures, I used the command line: https://bitcoin.stackexchange.com/questions/46455/verifying-a-bitcoin-trx-on-the-unix-cmd-line-with-openssl  

---

### Answer by username_3 on 2019-11-16. Score: 2

Here is an ECC calculator for the Secp256k1 curve that I'm programming in Java.
<https://github.com/MrMaxweII/Secp256k1-Calculator>

> **Comments:**
> **username_4**: for build modern GUI swing you can use this [library](https://github.com/username_4/material-ui-swing)  

---

