PKCS#7 Encryption Recipient Certificate List (0x0019).

This field MAY contain information about each of the certificates used in encryption processing and it can be used to identify who is allowed to decrypt encrypted files. This field should only appear in the archive extra data record. This field is not required and serves only to aid archive modifications by preserving public encryption key data. Individual security requirements may dictate that this data be omitted to deter information exposure.

         Value     Size     Description
         -----     ----     -----------
(CStore) 0x0019    2 bytes  Tag for this "extra" block type
         TSize     2 bytes  Size of the store data
         Version   2 bytes  Format version number - must 0x0001 at this time
         CStore    (var)    PKCS#7 data blob

See the section describing the Strong Encryption Specification for details. Refer to the section in this document entitled "Incorporating PKWARE Proprietary Technology into Your Product" for more information.