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 49 of 245 (D998200115-17)
6.9 MagnePrint Data Length (HID | GATT | SLIP)
This one-byte value indicates the number of bytes in the Encrypted MagnePrint Data value, which is
always a multiple of 8 bytes in length. This value is zero if there is no MagnePrint data. After the
Encrypted MagnePrint data is decrypted, there may be fewer bytes of MagnePrint data than indicated by
this value. The number of bytes of decrypted MagnePrint data is indicated by MagnePrint Absolute
Data Length.
If the device is set to a security level below Security Level 3, it uses the current value of Property 0x15 -
MagnePrint Flags to determine the behavior of this value.
6.10 MagnePrint Absolute Data Length (HID | TLV | GATT | SLIP)
This one-byte value indicates the number of usable bytes in Encrypted MagnePrint Data value after
decryption.
If the device is set to a security level below Security Level 3, it uses the current value of Property 0x15 -
MagnePrint Flags to determine the behavior of this value.
6.11 Encrypted MagnePrint Data
This value contains Encrypted MagnePrint data, which when decrypted generally yields a 54-byte value.
The least significant bit of the first byte of data in the decrypted value corresponds to the first bit of
MagnePrint data.
If the device is set to a security level below Security Level 3, it uses the current value of Property 0x15 -
MagnePrint Flags to determine the behavior of this value.
To derive a decrypted MagnePrint value to authenticate a card, the host should do the following:
1) If the device transmitted a MagnePrint Data Length, truncate the data to that length to strip out
protocol padding and yield a decryptable data block.
2) Decrypt the data block.
3) If the device transmitted a MagnePrint Absolute Data Length (HID | TLV | GATT | SLIP),
truncate the data to that length to yield the MagnePrint data.
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