Update Readme

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trivernis 5 years ago
parent b5ce371875
commit d02a8a89b4

@ -3,6 +3,8 @@ name = "bdflib"
version = "0.1.0" version = "0.1.0"
authors = ["trivernis <trivernis@gmail.com>"] authors = ["trivernis <trivernis@gmail.com>"]
edition = "2018" edition = "2018"
license-file = "LICENSE"
license = "GPL-3"
[lib] [lib]
name = "bdf" name = "bdf"

@ -1 +1,70 @@
bdflib # bdflib
This library provides methods to read and write Binary Dictionary Format files that can be used to represent rainbow tables.
## Binary Dictionary File Format (bdf)
```
<BDF> = <Header><Chunk(META)><Chunk(HTBL)>[<Chunk(DTBL)>]
```
All `u8` format are unsigned BigEndian numbers.
### Header
Raw (hex) `42 44 46 01 52 41 49 4e 42 4f 57`
| Position | Name | Value | Meaning |
| -------- | ----------- | --------- | ---------------------------------- |
| 0-2 | Format | `BDF` | Indicates the bdf Format |
| 3-4 | Version | u32 | The revision of the format (0x01) |
| 4-10 | to be fancy | `RAINBOW` | The word "Rainbow" because why not |
### Chunk
| Position | Name | Value | Meaning |
| ------------- | ---------- | ----- | ------------------------------ |
| 0-3 | length (l) | u32 | the length of the data chunk |
| 4-7 | name | ASCII | the name of the chunk |
| 8-l | data | any | the data of the chunk |
| l + 1 - l + 5 | crc | crc | the crc sum value of the chunk |
### Meta Chunk
The format of the data inside the `META` chunk.
The data is mandatory for the file to be interpreted and the chunk should be the first chunk in the file.
| Position | Name | Value | Meaning |
| -------- | ----------------------- | ---------------- | ---------------------------------------------------------------- |
| 0-3 | chunk count | u32 | The number of `DTBL` chunks in the file |
| 4-7 | entries per chunk | u32 | The maximum number of Data Rows in each chunk |
| 8-15 | total number of entries | u64 | The total number Data Rows in the file |
| 16-19 | compression method | ASCII/0x00000000 | The name of the compression method or null bytes if none is used |
### Data Row
The format inside the `DTBL` chunk.
A chunk contains multiple data rows.
| Position | Name | Value | Meaning |
| --------- | ---------- | ----- | --------------------------------------------------------------------------------------- |
| 0-3 | length(lt) | u32 | the total length of the data row |
| 4-7 | length (l) | u32 | the length of the password string |
| 8-l | password | UTF-8 | The password string |
| 1: l+1 - l+5 | type | u32 | the id of the hash function |
| l+6 - l+x | hash | any | the value of the hash function. The length has to be looked up by the hash functions ID |
| goto 1 |
### Hash Entry
The format inside the `HTBL` chunk.
Just like the DataRow the HashEntry is contained in the chunk multiple times.
| Position | Name | Value | Meaning |
| --------- | ------------- | ----- | --------------------------------------------------- |
| 0-3 | ID | u32 | the id of the entry that is used in the data tables |
| 4-7 | output length | u32 | the length of the output of the hash function |
| 8-11 | length | u32 | the length of the hash functions name |
| 12-length | name | ASCII | the name of the hash function |
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