Answer:
To check for the data encryption key and encryption algorithm, you can send the "81-04" with the data "05" first (see screenshot below for steps):
And then refer to the NEO IDG excerpt below for the definition of the response data:
For example, the response highlighted in the screenshot above for the data key slot (05) is "01443054453030", below is the breakdown with meanings:
01 - a valid key exists in key slot 5 which is the data encryption key
4430 - this is "D0" in ASCII means the key is used to encrypt data
54 - This is "T" in ASCII means the reader is on the TDES encryption algorithm
45 - This is "E" in ASCII means the key is for Encryption only
3030 - This is "00" in ASCII means the key version number is not used
This method applies to all NEO products
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