The authentication device then generates, using {TAIL ~ the same code generation} algorithm, {HEAD ~ an expected code value} based on a second secret key and compares the expected code value to the service authentication code 
using
The authentication device then generates , using { TAIL ~ the same code generation } algorithm , { HEAD ~ an expected code value } based on a second secret key and compares the expected code value to the service authentication code
OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH