Difference between revisions of "BCAT Content Container"
(Created page with "Content downloaded by BCAT normally uses this container. =Header= {| class="wikitable" border="1" |- ! Offset ! Size ! Description |- | 0x0 | 0x4 | Magicnum...") |
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| 0x10 | | 0x10 | ||
| 0x10 | | 0x10 | ||
| − | | Base IV | + | | Base IV/CTR |
|- | |- | ||
| 0x20 | | 0x20 | ||
| Line 42: | Line 42: | ||
The header is 0x120-bytes. | The header is 0x120-bytes. | ||
| + | |||
| + | =Key generation= | ||
| + | The AES keydata is the output from pkcs5_pbkdf2_hmac, with SHA256: password = <passphrase string loaded from file>, salt = <below salt string>, and iteration_count=4096. | ||
| + | |||
| + | The passphrase is loaded from "<basepath>/passphrase.bin". passphrase_len=strlen(passphrase). 0x40-bytes are read from the file, with 0x0 being written to passphrase[total_read_data]. salt_len = strlen(salt). | ||
| + | |||
| + | salt is the snprintf output from "%016llx%s", where the former is presumably the titleID, while the latter is secretdata_str. secretdata_str = secretdata_array[<value of hdr+0x7>]. | ||
| + | |||
| + | Settings config for 1-byte <"bcat", "production_mode"> is loaded, when retval!=1 or output_config!=0, then secretdata_array = secretdata_array0(retail), otherwise secretdata_array = secretdata_array1(devunit). The latter only contains empty strings, while the former contains lower-case hex strings. There are 16 entries in each array. | ||
Revision as of 23:14, 6 August 2017
Content downloaded by BCAT normally uses this container.
Header
| Offset | Size | Description |
|---|---|---|
| 0x0 | 0x4 | Magicnum "bcat" |
| 0x4 | 0x1 | ? |
| 0x5 | 0x1 | Crypto type |
| 0x6 | 0x1 | ? |
| 0x7 | 0x1 | Secret-data index |
| 0x8 | 0x8 | Normally zero? |
| 0x10 | 0x10 | Base IV/CTR |
| 0x20 | 0x100 | RSA-2048 signature, presumably. |
The header is 0x120-bytes.
Key generation
The AES keydata is the output from pkcs5_pbkdf2_hmac, with SHA256: password = <passphrase string loaded from file>, salt = <below salt string>, and iteration_count=4096.
The passphrase is loaded from "<basepath>/passphrase.bin". passphrase_len=strlen(passphrase). 0x40-bytes are read from the file, with 0x0 being written to passphrase[total_read_data]. salt_len = strlen(salt).
salt is the snprintf output from "%016llx%s", where the former is presumably the titleID, while the latter is secretdata_str. secretdata_str = secretdata_array[<value of hdr+0x7>].
Settings config for 1-byte <"bcat", "production_mode"> is loaded, when retval!=1 or output_config!=0, then secretdata_array = secretdata_array0(retail), otherwise secretdata_array = secretdata_array1(devunit). The latter only contains empty strings, while the former contains lower-case hex strings. There are 16 entries in each array.