| Feature Name | Description | 
|---|
           | DKIM_FEATURE_DIFFHEADERS | Underlying code required to provide the
	                        dkim_diffheaders()
	                        facility. | 
           | DKIM_FEATURE_PARSE_TIME | Underlying code required to provide the
	                        dkim_get_msgdate()
	                        facility. | 
           | DKIM_FEATURE_QUERY_CACHE | Underlying code required to do local caching
	                        of DNS replies (i.e., key records). | 
           | DKIM_FEATURE_SHA256 | Underlying code required to do SHA256 hashing
	                        when signing or verifying. | 
           | DKIM_FEATURE_DNSSEC | Underlying code required to conduct DNSSEC
	                        evaluation of replies. | 
           | DKIM_FEATURE_OVERSIGN | Capability to "over-sign" header fields
	                        to prevent later addition of signed
				fields. |