Written by Vitaly Kamluk

3 minute read

This section describes instructions to modify Bitscout configuration and script files to accommodate your requirements. Note: this may NOT be applicable to older Bitscout branch (16.04).

Customization Approach

Please analyse current scripts before customizing them. Here are some general advice for Bitscout contributors:

1. Stick to current design and template-based strategy.
2. Make the code as short and as readable as possible. Do not overload it with complex expressions.
3. If you add another stage (script) into automake.sh make sure that running it repeatedly does not break the final product. I.e. if your script adds another user, make sure that it verifies first that this user has not been added already.

You should be able to add modification to files inside ./resources and ./scripts directory and rerun only those scripts that apply your changes to the final product. There is no need to restart build process from scratch every time.

Should you need to add some manual temporary modifications (i.e. install/remove/configure software packages) you can enter target filesystem using ./scripts/chroot_enter.sh script. To quit, press Ctrl+D or type exit and press Enter.

Bitscout Release Size Levels

Bitscout offers 3 basic release size level: minimal (1), optimal (2) and maximum (3). Depending on this, it includes libraries and software that you may want to have during forensic operation. You need to find your favorite size depending on media size, acceptable ISO file network transfer time, etc. You can change your release size level to another one at any time in GLOBAL_RELEASESIZE variable in config/bitscout-build.conf.

Bitscout Cryptographic Keys Length

By default, Bitscout uses public key cryptography (SSH, OpenVPN) with 2048-bit keys. Should you need to increase the keylength change CRYPTOKEYSIZE variable in config/bitscout-build.conf.

Custom Kernel

Config file config/bitscout-build.conf also offers to change the choice of using custom kernel (variable GLOBAL_CUSTOMKERNEL). In this case Bitscout will compile a custom kernel for you and apply kernel patch to enforce write-blocking mechanism on the kernel level. Credits for the patch go to Maxim Suhanov (more details in his project: https://github.com/msuhanov/Linux-write-blocker).

VPN Settings

During initial run, it will prompt for VPN Server, protocol and port number which shall not be prompted on subsequent run, however it can be modified manually.
To modify the VPN settings:

1. Go to config folder
   cd ./config
2. Open bitscout-build.conf for editing, using a text editor (e.g. vi)
   vi bitscout-build.conf
3. Update the entries accordingly
   GLOBAL_VPNSERVER=new_vpn_server
GLOBAL_VPNPROTOCOL=new_protocol_type
GLOBAL_VPNPORT=new_port_number
4. Save the config file.
5. When automake.sh script is executed again, it will use the settings from config/bitscout-build.conf Note that you do not need to re-download all files when rebuilding after change of settings.

Architecture

Bitscout constructor builds 64-bit system by default. However, if you need to run on older 32-bit setup, you may want to use 32-bit build. In this case you can change the base architecture in config/bitscout-build.conf file (change GLOBAL_BASEARCH variable from amd64 to i386) before making the ISO file.