The field tag that identifies a field contained in a cryptographic service message; the field tag identifies the contents of the accompanying Field Contents
Identity of Key Distribution Center (CKD) or Key Translation Center (CKT)
IDD
Discontinued Key Name
IDU
Identity of Ultimate Recipient (the Security Recipient)
KD
Data Key
KDU
Data Key, Notarized
KK
Key - Encrypting Key
KKU
Key - Encrypting Key Notarized
MAC
Message Authentication Code
NOS
Notarization Flag
PKK
Key - Encrypting Key Pair (*KK)
PKKU
Key - Encrypting Key Pair, Notarized (*KKU)
SUBF
Subfield of Previous Field Tag
Indicates that the previous field tag (other than SUBF) has a subfield and the accompanying field content is the subfield value without the ANSI X9.17 subfield delimiter