Create SecurityKey from signing certificate thumbprint
<p>I'm trying to migrate from FederationAuthenticationModule (WS FAM?) to OWIN WsFederationAuthentication middleware. So far, so good except that, for some customers we only have the thumbprint of their signing certificate.</p>

<p>For WS FAM, this was enough as <a href="https://msdn.microsoft.com/nl-be/library/system.identitymodel.tokens.configurationbasedissuernameregistry.addtrustedissuer%28v=vs.110%29.aspx" rel="nofollow"><code>ConfigurationBasedIssuerNameRegistry.AddTrustedIssuer()</code></a> only needs the thumbprint of the signing certificate.</p>

<p>The OWIN middleware however, needs a <a href="https://msdn.microsoft.com/en-us/library/system.identitymodel.tokens.securitykey%28v=vs.110%29.aspx" rel="nofollow"><code>SecurityKey</code></a>-derived type in the <code>WsFederationConfiguration.SigningKeys</code>-collection. While I can create a <code>SecurityKey</code> from a certificate, I can't find a way to create one from the thumbprint only.</p>

<p>Any ideas how I can create a <code>SecurityKey</code> from a certificate thumbprint only or any other way to get the WsFederationAuthentication middleware working with only thumbprints?</p>