Code identifying the security algorithms and methods applied for this level of interchange

If S2S01 is "AA", "BB", "AC" or "BC", then S2S04 is required.

If S2S01 is "BB", "EE", "AC" or "EC", then S2S06 is required.

Unique designation (identity) of the cryptographic process that performs authentication or encryption on data to be interchanged, or originates a cryptographic service message Note: X9 has a minimum length of 4 characters for the security originator; no mechanism, or registration method is provided by X9 or X12 to guarantee the uniqueness of the identifier

X9 has a required minimum length of four characters for S2S02 (security originator). No mechanism, or registration method, is provided by X9 or X12 to guarantee uniqueness of the identifier.

Unique designation (identity) of the cryptographic process that performs authentication or decryption on received data, or is the destination of a cryptographic service message Note: X9 has a minimum length of 4 characters for the security recipient; no mechanism, or registration method is provided by X9 or X12 to guarantee the uniqueness of the identifier

X9 has a required minimum length of four characters for S2S03 (security recipient). No mechanism, or registration method, is provided by X9 or X12 to guarantee uniqueness of the identifier.

Name of the key used for authentication; this name is mutually known to the security originator and the security recipient, is unique for this relationship, and is intended to allow the changing of the key from time to time Note: The special key name "0123456789ABCDEF" is reserved for the hexidecimal value 0123456789ABCDEF (i.e. a fixed non-secret value) to provide a well-known value for data integrity testing only)

In S2S04 the special name "01234567890ABCDEF" is reserved for the hexadecimal value 01234567890ABCDEF (i.e., a fixed nonsecret value) to provide a well-known value for data-integrity testing only.

Authentication options

Length of data is the number of character positions of the compressed or encrypted/filtered text; when data is plain text, this field shall be absent

The archival representation of a 64-bit value expressed in hexadecimal notation as 16 ASCII characters from the set of characters (0..9, A..F); the 64-bit value is used as a starting point for encryption of a data sequence to increase security by introducing cryptographic variance and to synchronize cryptographic equipment; a new Initialization Vector (IV) shall be used for each message; the IV shall not be intentionally reused; the 64-bit binary value, not its ASCII representation, is used for the cryptographic process; in the interchange process, the resultant encrypted and filtered 64-bit IV is sent; the hexadecimal notation is the representation for archiving purposes; the IV shall be a random or pseudo-random number; when encrypted, the IV must be decrypted using the Electronic Code Book (ECB) mode and the same key used to encrypt the message