/// <summary>
/// Validates the signature using the public part of the asymmetric key given as parameter.
/// </summary>
/// <param name="key">The key.</param>
/// <returns><code>true</code> if the signature is present and can be verified using the given key.
/// <code>false</code> if the signature is present, but can't be verified using the given key.</returns>
/// <exception cref="InvalidOperationException">If the query is not signed, and therefore cannot have its signature verified. Use
/// the <code>IsSigned</code> property to check for this situation before calling this method.</exception>
public bool CheckSignature(AsymmetricAlgorithm key)
{
if (key == null)
{
throw new ArgumentNullException("key");
}
if (!(key is DSA || key is RSA))
{
throw new ArgumentException("The key must be an instance of either DSA or RSACryptoServiceProvider.");
}
if (!IsSigned)
{
throw new InvalidOperationException("Query is not signed, so there is no signature to verify.");
}
var hashAlgorithm = XmlSignatureUtils.GetHashAlgorithm(SignatureAlgorithm);
var hash = hashAlgorithm.ComputeHash(Encoding.UTF8.GetBytes(_signedquery));
if (key is RSA)
{
var rsa = (RSA)key;
return(VerifyHash(hashAlgorithm, rsa, hash, DecodeSignature()));
}
else
{
var dsa = (DSA)key;
return(dsa.VerifySignature(hash, DecodeSignature()));
}
}