/// <summary>
/// Calculates the signature for a given message.
/// </summary>
/// <param name="signedMessage">The message to sign or verify.</param>
/// <param name="association">The association to use to sign the message.</param>
/// <returns>The calculated signature of the method.</returns>
protected string GetSignature(ITamperResistantOpenIdMessage signedMessage, Association association)
{
Requires.NotNull(signedMessage, "signedMessage");
Requires.That(!string.IsNullOrEmpty(signedMessage.SignedParameterOrder), "signedMessage", "SignedParameterOrder must not be null or empty.");
Requires.NotNull(association, "association");
// Prepare the parts to sign, taking care to replace an openid.mode value
// of check_authentication with its original id_res so the signature matches.
MessageDictionary dictionary = this.Channel.MessageDescriptions.GetAccessor(signedMessage);
var parametersToSign = from name in signedMessage.SignedParameterOrder.Split(',')
let prefixedName = Protocol.V20.openid.Prefix + name
select new KeyValuePair <string, string>(name, dictionary.GetValueOrThrow(prefixedName, signedMessage));
byte[] dataToSign = KeyValueFormEncoding.GetBytes(parametersToSign);
string signature = Convert.ToBase64String(association.Sign(dataToSign));
if (Logger.Signatures.IsDebugEnabled)
{
Logger.Signatures.DebugFormat(
"Signing these message parts: {0}{1}{0}Base64 representation of signed data: {2}{0}Signature: {3}",
Environment.NewLine,
parametersToSign.ToStringDeferred(),
Convert.ToBase64String(dataToSign),
signature);
}
return(signature);
}