Hash a Block of Data

Command:

Hash a block of data.

Notes:

It is the responsibility of the application program to ensure that the amount of data supplied in this command does not cause a buffer overflow.

Field

Length & Type

Details

COMMAND MESSAGE

Message header

m A

(Subsequently returned to the Host unchanged).

Command code

2 A

Value GM.

Hash identifier

2 N

Identifier of the hash algorithm used to hash the data.

Data length

5 N

Length of the message data to be hashed.

Message data

n B

Data to be hashed.

End message delimiter

1 C

Optional.  Must be present if a message trailer is present. Value X’19.

Message trailer

n A

Optional.  Maximum length 32 characters.

RESPONSE MESSAGE

Message header

n A

Returned to the Host unchanged.

Response code

2 A

Value GN.

Error code

2 N

00 : No error

05 : Invalid hash identifier

15 : Error in input data

80 : Data length error

Hash value

n B

Hash result (length depends on the algorithm used)

End message delimiter

1 C

Present only if present in the command message. Value X’19.