Try this:
public static bool DoesKeyExists(string containerName)
{
var cspParams = new CspParameters
{
Flags = CspProviderFlags.UseExistingKey,
KeyContainerName = containerName
};
try
{
var provider = new RSACryptoServiceProvider(cspParams);
}
catch (Exception e)
{
return false;
}
return true;
}
similiar question: How to check if RSA key container exists in .NET