getExtraData

Extra data is a parametrized property that allows the client to store additional data within the signature object after capture.

For example, if a signature is being manually validated, the system may find it convenient to store the result in the signature itself, rather than as an independent data item.

Each extra data item must be given an identifying key name under a string value named key and an associate value string named value. There can be only one value for each key and once written the key cannot be modified or removed. All extra data key pairs are protected by the signature object integrity hash.

Parameters
Key: String indicating the name of the extra data to be retrieved. If this string is empty it will retrieve a string with all the extra data.

Return values
String with the extra data value.