Could not load type 'System.Security.Cryptography.SHA512CryptoServiceProvider' from assembly Version=2.4.0.0, Culture=neutral
<p>I load Cryptography Providers dynamically using this code</p>

<pre><code>string hashAlgoTypeString =
         ConfigurationManager.AppSettings[HashAlgorithmProviderConfiguration];
if (hashAlgoTypeString != null)
{
    Type hashAlgoType = Type.GetType(hashAlgoTypeString, true);
    return (HashAlgorithm) Activator.CreateInstance(hashAlgoType);
}
</code></pre>

<p>The hashAlgoTypeString is a full qualified name to one of <em>CryptoServiceProviders</em> set in my <em>Web.config</em></p>

<p>I don't have any problems loading these</p>

<pre><code>System.Security.Cryptography.DESCryptoServiceProvider
System.Security.Cryptography.DSACryptoServiceProvider
System.Security.Cryptography.MD5CryptoServiceProvider
System.Security.Cryptography.RC2CryptoServiceProvider
System.Security.Cryptography.RNGCryptoServiceProvider
System.Security.Cryptography.RSACryptoServiceProvider
System.Security.Cryptography.SHA1CryptoServiceProvider
System.Security.Cryptography.TripleDESCryptoServiceProvider
</code></pre>

<p>However, the following CryptoServiceProviders all throw the "<em>Could not load type</em>" exception.</p>

<pre><code>System.Security.Cryptography.AesCryptoServiceProvider
System.Security.Cryptography.SHA256CryptoServiceProvider
System.Security.Cryptography.SHA384CryptoServiceProvider
System.Security.Cryptography.SHA512CryptoServiceProvider
</code></pre>

<p>What could be the issue with these four providers?</p>

<p>I'm running Windows 7 x64 with .NET 4.5.2</p>

<p>In GAC </p>

<pre><code>System.Security v2.0.0.0
mscorlib v2.0.0.0 for x86 and AMD64
</code></pre>

<p><strong>Edit</strong></p>

<p>I am able to instantiate all four</p>

<pre><code>        var Aes = new System.Security.Cryptography.AesCryptoServiceProvider();
        var sha256 = new System.Security.Cryptography.SHA256CryptoServiceProvider();
        var sha384 = new System.Security.Cryptography.SHA384CryptoServiceProvider();
        var sha512 = new System.Security.Cryptography.SHA512CryptoServiceProvider();
</code></pre>

<p>and use them from my code without issues. </p>