TrenchBoot Use Cases¶
TrenchBoot is meant to be a universal framework to enable building integrity in the launch process of systems. To relate to real world usage, it is good to have a set of use cases that explain a subset of situations where TrenchBoot is applicable and how it would work in those situations. Below are a series of use cases that are actively being investigated and/or worked on.
Crowd Sourcing Integrity¶
There is currently no known public authority available to verify BIOS/Firmware PCR values. TrenchBoot would like to become such an authority but there is the challenge of how to obtain all these values in a manner that provide assurance to the authenticity of the values. Crowd sourcing provides the best means to collect the largest and most diverse set of values. The challenge with crowd sourcing the values is how to establish authenticity of the values. This challenge can be overcome with a TrenchBoot based live CD that establishes an attestation identity provisioned by a TrenchBoot Attestation Certificate Authority (ACA).
Network Attestation Launch¶
An individual or enterprise may not want to allow a system to boot on their network unless it is running a known configuration. When TrenchBoot is installed onto a system it will work in conjunction with a TrenchBoot ACA (public or private instance) that provides a key management service. TrenchBoot will hold a portion of a Shamir Secret Sharing key with another portion held by the key management service. For the system to boot it will attest to the key management service to obtain a key fragment that will allow it to unlock the system disk.
Travel Laptop 2FA Launch¶
When travelling there are times when an individual loses positive control of their device. During these times attackers can launch physical access attacks. For this configuration TrenchBoot will "double chain wrap" the encryption key for decrypting the system where each chain wrap correlates to an authentication factor. Working internal to external, the system drive key is encrypted with the first wrap key that is in turned encrypted with the second wrap key. The first wrap key is stored on a removable token device, e.g. YubiKey, and the second wrap key is sealed in a TPM NVRAM slot. For a system to boot it must have launched with the correct firmware and the token must be present.