White-box cryptography aims to protect key use in hostile client environments. Evaluate resistance within a defined threat model rather than accepting absolute claims.
Evaluation approach
Software key representations and transformed operations aim to increase analysis effort. Their assumptions differ from hardware-backed storage and server-side processing.
Application example
If offline requirements require client-side key operations, document the threat model and renewal plan explicitly.
Limits and considerations
Software concealment must not be described as unconditional non-extractability or prevention of unauthorized use.
Protecting the key versus protecting its use
Making extraction harder is different from preventing someone from using the software as a key-operation oracle. Assess both risks separately.
Define the attacker's observation and modification capabilities. Plan renewal and revocation. Compare hardware alternatives and operations that could move to the server under the same threat model.
Checks and decisions
- Ask for threat assumptions
- Request independent testing
- Define the key lifecycle
Compare white-box options with hardware and offline requirements using evidence rather than slogans.
Sources
The primary references above provide the technical basis. Example workflows and evaluation suggestions are this publication’s explanations, not independent test results for a particular product.