Delegation Trust Chain
A delegation trust chain records each hop that transfers authority, so a resource server can audit the full path from original principal through every intermediary rather than trusting the.
Definition
A delegation trust chain is a sequence of signed or attested assertions where each delegate records who delegated to it and under what constraints, so that the final resource server can reconstruct the full authority path and verify no hop exceeded its granted scope.
Context and scope
Applied in distributed workflow authorization, service-to-service call chains, and federated identity where authority passes through multiple intermediaries.
Common misconceptions
- The immediate caller authenticated is sufficient — it proves the caller, not that the caller was authorized by the original principal to perform this action
- Delegation chains are too expensive to verify — the verification is a signature chain check; the cost is in building the chain, which token standards already encode
Anti-patterns
- Accepting a bearer token without the delegation history, trusting whatever scope the last hop claims
- Building a delegation chain that intermediaries can extend without bound, allowing authority inflation
Related concepts
Authoritative source
What it is
A delegation trust chain is a sequence of signed or attested assertions where each delegate records who delegated to it and under what constraints, so that the final resource server can reconstruct the full authority path and verify no hop exceeded its granted scope. Applied in distributed workflow authorization, service-to-service call chains, and federated identity where authority passes through multiple intermediaries. The threat model determines which controls apply: preventive controls block exploits, detective controls surface violations, and corrective controls restore integrity after an incident.
How it works
Effective implementations layer controls so that no single bypass compromises the asset. Verification happens at trust boundaries, not just at the perimeter. Cryptographic primitives are selected for the concrete property needed — unforgeability, indistinguishability, or non-malleability — and never composed ad hoc. Failure modes fail closed: a verification error denies rather than allows.
When to enforce and pitfalls
Enforce wherever an attacker can influence input that crosses a trust boundary. Common pitfalls include treating obfuscation as a control, relying on secrecy of the algorithm rather than the key, and auditing the happy path while ignoring error-handling branches where bypasses often hide. Rate-limit and log every verification attempt so brute-force and oracle attacks become visible.