Adding Hardware Security with the CryptoCape - BeagleBone for Secret Agents - page 79

00000080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
|................|
00000090 00 00 a0 2f 00 00 00 00 00 00 c0 17 00 00 00 00
|.../............|
000000a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
|................|
*
000000e0 00 00 00 00 00 00 00 00 00 00 00 00 01 f4 00 00
|................|
000000f0 00 00 00 00 47 50 47 20 46 69 6e 67 65 72 70 72
|....GPG Fingerpr|
00000100 69 6e 74 3a 20 30 78 42 35 39 31 39 42 31 41 43
|int: 0xB5919B1AC|
00000110 37 31 33 35 39 30 35 46 34 36 36 39 43 38 34 37
|7135905F4669C847|
00000120 42 46 41 35 30 33 31 42 44 32 45 44 45 41 36 0a
|BFA5031BD2EDEA6.|
00000130 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
|................|
*
00008000
If you walk through the SRM EEPROM data format, you should be able to match the
fields with those in the CryptoCape EEPROM. The two most important fields are the
Board Name , which starts at offset 6 and is 32 bytes in length and the Version , which
starts at byte 38 and is 4 bytes in length. From the previous example, the board name is
BB-BONE-CRYPTO and the version is 00A0 . These two components are needed to name
the DTS file in the next section. Starting at offset 244, the manufacturer can place any
nonvolatile information. The CryptoCape contains the GNU Privacy Guard ( GPG ) fin-
gerprint of the author's GPG public key, which is used to sign software packages and e-
mail. In your cape, you could populate this with initial values for software or something
similar.