Magtek eDynamo, Руководство программиста

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6 - Magnetic Stripe Card Data Sent from Device to Host (MSR Only | Keypad Entry Only)
eDynamo| Secure Card Reader Authenticator | Programmer’s Manual (COMMANDS)
Page 44 of 245 ( D998200115-17 )
6.7 Encrypted Track Data
If decodable track data exists for a given track, the device returns it in the corresponding Track x
Encrypted Data value, described in the subsections below.
When the device is transmitting data in HID, GATT, or SLIP format, the
Encrypted Data values are
always 112 bytes long, which is the maximum number of bytes that can be encoded on a card. However,
the length of actual valid data in each value may be less than 112 bytes, and is stored in the corresponding
Encrypted Data Length value. The host software should ignore data located beyond the data length
reported by the device.
The device decodes the data from each track on the card and converts it to ASCII, and includes all data
starting with the start sentinel and ending with the end sentinel.
If the device is in a security level below
Security Level 3 , it sends the resulting track data in the Track x
Encrypted Data values unencrypted. If the device is in Security Level 3 or Security Level 4 , it encrypts
the data before sending. For information about how the device encrypts the data and how the host should
decrypt it, see section
5 Encryption, Decryption, and Key Management .
6.7.1 Track 1 Encrypted Data Length (HID | GATT | SLIP)
This one-byte value indicates the number of bytes in the Track 1 Encrypted Data value. The value is
always a multiple of 8. If the value is 0, the device found no data on the track or encountered an error
decoding the track.
After data is decrypted, there may be fewer bytes of decoded track data than indicated by this value. The
number of bytes of decoded track data is indicated by the
Track 1 Absolute Data Length value.
Format Where to Find Value
HID Usage 0x28
Streaming N/A
TLV N/A
GATT/SLIP Offset 3
6.7.2 Track 2 Encrypted Data Length (HID | GATT | SLIP)
This one-byte value indicates the number of bytes in the Track 2 Encrypted Data value. The value is
always a multiple of 8. If the value is 0, the device found no data on the track or encountered an error
decoding the track.
After data is decrypted, there may be fewer bytes of decoded track data than indicated by this value. The
number of bytes of decoded track data is indicated by the
Track 2 Absolute Data Length (HID | GATT
| SLIP) value.
Format Where to Find Value
HID Usage 0x29
Streaming N/A
TLV N/A