/// <summary>
/// Encodes the specified association data bag.
/// </summary>
/// <param name="secret">The symmetric secret.</param>
/// <param name="expiresUtc">The UTC time that the association should expire.</param>
/// <param name="privateAssociation">A value indicating whether this is a private association.</param>
/// <returns>
/// The association handle that represents this association.
/// </returns>
public string Serialize(byte[] secret, DateTime expiresUtc, bool privateAssociation)
{
var associationDataBag = new AssociationDataBag {
Secret = secret,
IsPrivateAssociation = privateAssociation,
ExpiresUtc = expiresUtc,
};
var formatter = AssociationDataBag.CreateFormatter(this.cryptoKeyStore, AssociationHandleEncodingSecretBucket, expiresUtc - DateTime.UtcNow);
return(formatter.Serialize(associationDataBag));
}
/// <summary>
/// Retrieves an association given an association handle.
/// </summary>
/// <param name="containingMessage">The OpenID message that referenced this association handle.</param>
/// <param name="privateAssociation">A value indicating whether a private association is expected.</param>
/// <param name="handle">The association handle.</param>
/// <returns>
/// An association instance, or <c>null</c> if the association has expired or the signature is incorrect (which may be because the OP's symmetric key has changed).
/// </returns>
/// <exception cref="ProtocolException">Thrown if the association is not of the expected type.</exception>
public Association Deserialize(IProtocolMessage containingMessage, bool privateAssociation, string handle)
{
var formatter = AssociationDataBag.CreateFormatter(this.cryptoKeyStore, AssociationHandleEncodingSecretBucket);
AssociationDataBag bag = new AssociationDataBag();
try {
formatter.Deserialize(bag, containingMessage, handle, Protocol.Default.openid.assoc_handle);
} catch (ProtocolException ex) {
Logger.OpenId.Error("Rejecting an association because deserialization of the encoded handle failed.", ex);
return(null);
}
ErrorUtilities.VerifyProtocol(bag.IsPrivateAssociation == privateAssociation, "Unexpected association type.");
Association assoc = Association.Deserialize(handle, bag.ExpiresUtc, bag.Secret);
return(assoc.IsExpired ? null : assoc);
}