cryptographicexception the parameter is incorrect
<p>I am using ECDSA with SHA1 encryption because I am trying to make a licencing activation for a desktop application. For that I use a PHP server to which I give PC information and the server gives me the public the key and then I want to validate the data in C#.</p>

<p>I generated this public key in PHP:</p>

<pre><code>"-----BEGIN PUBLIC KEY-----
MDIwEAYHKoZIzj0CAQYFK4EEAAYDHgAEKzL3PFVVo3IWftdEYmwiSO/4zULGM/wB
8BrLjQ==
-----END PUBLIC KEY-----";
</code></pre>

<p>I used the code from here <a href="http://securitydriven.net/inferno/" rel="nofollow">http://securitydriven.net/inferno/</a> To get to this</p>

<pre><code>byte[] thePublicKeyToBytes = GetBytesFromPEM(thePublicKey2, "PUBLIC KEY");
CngKey dsaKeyPublic2 = thePublicKeyToBytes.ToPublicKeyFromBlob();

byte[] theRestToBytes = GetBytes(theRestInBinary);
byte[] meinData = GetBytes("Blabla");

using (var ecdsa = new ECDsaCng(dsaKeyPublic2) { HashAlgorithm = CngAlgorithm.Sha1 }) // verify DSA signature with public key
{
    if (ecdsa.VerifyData(meinData, theRestToBytes)) MessageBox.Show("Signature verified.");
    else MessageBox.Show("Signature verification failed.");
}
</code></pre>

<p>where the procedure is:</p>

<pre><code>byte[] GetBytesFromPEM(string pemString, string section)
{
    var header = String.Format("-----BEGIN {0}-----", section);
    var footer = String.Format("-----END {0}-----", section);

    var start = pemString.IndexOf(header, StringComparison.Ordinal) + header.Length;
    var end = pemString.IndexOf(footer, start, StringComparison.Ordinal) - start;

    if (start &lt; 0 || end &lt; 0)
    {
        return null;
    }

    return Convert.FromBase64String(pemString.Substring(start, end));
}
</code></pre>

<p>The problem is that I get this exception "cryptographicexception the parameter is incorrect" at this line:</p>

<pre><code>CngKey dsaKeyPublic2 = thePublicKeyToBytes.ToPublicKeyFromBlob();
</code></pre>

<p>I can't show the inferno's public key, but I saw that the length of their key is 384. Is this where I am doing it wrong? The length of the generated public key?</p>