user323: Which programming languages have some ready libraries that support Bitcoin's ECDSA curve - secp256k1?

user323: I've modified a library for Google Go to support a few of the Koblitz Curves, including secp256k1. It is available here.

user3347: There's a dedicated C-library for this curve. This is probably the most widely scrutinized library, and it probably has the best performance. Wrappers for other languages are available.
https://github.com/bitcoin/secp256k1

user117: The Bouncy Castle library provides support for all languages on the Java VM
This library (and now a derivative library called Spongy Castle) is used in the BitCoinJ library. 
The Bouncy Castle library was unfortunately implemented badly in Android which lead to code conflicts that required complex workarounds. Spongy Castle solved those problems making the Java and Android versions work much more cleanly with each other.
There is an interesting discussion on the choice of secp256k1 by Satoshi on the forums.
The languages currently supported by the JVM includes (and I quote):

Java
Clojure, a functional Lisp dialect
Groovy, a scripting language
Scala, an object-oriented and functional programming language
JavaFX Script, a scripting language targeting the Rich Internet Application domain (discontinued 2010)
JRuby, an implementation of Ruby
Jython, an implementation of Python
Rhino, an implementation of JavaScript
AspectJ, an aspect-oriented extension of Java


user1012: The Bouncy Castle project allows for this and it runs on the Java VM (as was mentioned earlier) as well as the .NET Runtime. An example of using it in C# is shown in this blog post. You can use the .NET version from Visual Basic .NET (as well as any of the other languages on the CLR as well, obviously).
For C++, look at the Crypto++ library which supports secp256k1.

323: <p>Which programming languages have some ready libraries that support Bitcoin's ECDSA curve - secp256k1?</p>
 323: <p>I've modified a library for <a href="http://golang.org/" rel="nofollow">Google Go</a> to support a few of the Koblitz Curves, including secp256k1. It is available <a href="https://github.com/ThePiachu/Golang-Koblitz-elliptic-curve-DSA-library" rel="nofollow">here</a>.</p>
 3347: <p>There's a dedicated C-library for this curve. This is probably the most widely scrutinized library, and it probably has the best performance. Wrappers for other languages are available.</p>

<p><a href="https://github.com/bitcoin/secp256k1" rel="nofollow">https://github.com/bitcoin/secp256k1</a></p>
 117: <p><strong>The <a href="http://www.bouncycastle.org/" rel="nofollow">Bouncy Castle</a> library provides support for all languages on the Java VM</strong></p>

<p>This library (and now a derivative library called <a href="http://rtyley.github.com/spongycastle/" rel="nofollow">Spongy Castle</a>) is used in the <a href="http://code.google.com/p/bitcoinj/" rel="nofollow">BitCoinJ</a> library. </p>

<p>The Bouncy Castle library was unfortunately implemented badly in Android which lead to code conflicts that required complex workarounds. Spongy Castle solved those problems making the Java and Android versions work much more cleanly with each other.</p>

<p>There is an <a href="https://bitcointalk.org/?topic=2699.0" rel="nofollow">interesting discussion</a> on the choice of secp256k1 by Satoshi on the forums.</p>

<p>The <a href="http://en.wikipedia.org/wiki/List_of_JVM_languages" rel="nofollow">languages currently supported by the JVM</a> includes (and I quote):</p>

<ul>
<li>Java</li>
<li>Clojure, a functional Lisp dialect</li>
<li>Groovy, a scripting language</li>
<li>Scala, an object-oriented and functional programming language</li>
<li>JavaFX Script, a scripting language targeting the Rich Internet Application domain (discontinued 2010)</li>
<li>JRuby, an implementation of Ruby</li>
<li>Jython, an implementation of Python</li>
<li>Rhino, an implementation of JavaScript</li>
<li>AspectJ, an aspect-oriented extension of Java</li>
</ul>
 1012: <p>The <strong>Bouncy Castle</strong> project allows for this and it runs on the Java VM (as was mentioned earlier) as well as the <strong>.NET Runtime</strong>. An example of using it in <strong>C#</strong> is shown in <a href="http://mytenpennies.wikidot.com/blog%3ausing-bouncy-castle" rel="noreferrer">this blog post</a>. You can use the .NET version from <strong>Visual Basic .NET</strong> (as well as any of the other languages on the CLR as well, obviously).</p>

<p>For C++, look at the <strong>Crypto++</strong> library which <a href="http://www.cryptopp.com/wiki/Keys_and_Formats" rel="noreferrer">supports secp256k1</a>.</p>
