Christian Nennemann
bbf557e54b
Move Go reference implementation to refimpl/go-lang/ and add new Python reference implementation in refimpl/python/. Update build.sh with renamed draft and simplified tool paths. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
108 lines
3.8 KiB
Markdown
108 lines
3.8 KiB
Markdown
# WIMSE ECT — Go Reference Implementation
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Go reference implementation of [Execution Context Tokens (ECTs)](../../draft-nennemann-wimse-execution-context-00.txt) for WIMSE. Implements ECT creation (ES256), verification (Section 7), DAG validation (Section 6), and an in-memory audit ledger (Section 9).
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## Layout
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```
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go-lang/
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├── go.mod, go.sum
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├── ect/ # library
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│ ├── types.go # Payload, Audience, constants
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│ ├── audience.go # aud marshal/unmarshal
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│ ├── create.go # Create(), GenerateKey()
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│ ├── verify.go # Parse(), Verify(), VerifyOptions
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│ ├── dag.go # ValidateDAG(), ECTStore
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│ ├── ledger.go # Ledger, MemoryLedger
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│ ├── config.go # Config, LoadConfigFromEnv()
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│ ├── jti_cache.go # JTICache for replay protection
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│ ├── errors.go # Sentinel errors (ErrExpired, ErrReplay, etc.)
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│ ├── validate.go # ValidateExt, ValidUUID, ValidateHashFormat
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│ └── *_test.go
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├── testdata/
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│ └── valid_root_ect_payload.json
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└── cmd/demo/ # two-agent workflow demo
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└── main.go
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```
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## Usage
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### Library
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```go
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import "github.com/nennemann/ect-refimpl/go-lang/ect"
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// Production: load config from environment
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cfg := ect.LoadConfigFromEnv()
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key, _ := ect.GenerateKey()
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payload := &ect.Payload{
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Iss: "spiffe://example.com/agent/a",
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Aud: ect.Audience{"spiffe://example.com/agent/b"},
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Iat: time.Now().Unix(),
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Exp: time.Now().Add(10*time.Minute).Unix(),
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Jti: "550e8400-e29b-41d4-a716-446655440000",
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ExecAct: "review_spec",
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Par: []string{},
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Pol: "policy_v1",
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PolDecision: ect.PolDecisionApproved,
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}
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compact, err := ect.Create(payload, key, cfg.CreateOptions("agent-a-key"))
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// Verify with optional replay cache
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store := ect.NewMemoryLedger()
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var jtiCache ect.JTICache
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if cfg.JTIReplaySize > 0 {
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jtiCache = ect.NewJTICache(cfg.JTIReplaySize, cfg.JTIReplayTTL)
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}
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opts := cfg.VerifyOptions()
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opts.VerifierID = "spiffe://example.com/agent/b"
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opts.ResolveKey = resolver
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opts.Store = store
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if jtiCache != nil {
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opts.JTISeen = jtiCache.Seen
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}
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parsed, err := ect.Verify(compact, opts)
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if err != nil { ... }
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if jtiCache != nil {
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jtiCache.Add(parsed.Payload.Jti)
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}
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store.Append(compact, parsed.Payload)
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```
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### Demo
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```bash
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cd refimpl/go-lang && go run ./cmd/demo
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```
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### Tests
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```bash
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cd refimpl/go-lang && go test ./ect/... -cover
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```
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Unit tests are in `ect/*_test.go`. Coverage target: **~90%** (run `go test ./ect/... -coverprofile=cover.out && go tool cover -func=cover.out`). Remaining uncovered lines are mostly Parse/Verify error paths that require custom JWS or multi-sig tokens.
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## Production configuration (environment)
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| Variable | Default | Description |
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|----------|---------|-------------|
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| `ECT_IAT_MAX_AGE_MINUTES` | 15 | Max age of `iat` (minutes). |
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| `ECT_IAT_MAX_FUTURE_SEC` | 30 | Max `iat` in future / clock skew (seconds). |
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| `ECT_DEFAULT_EXPIRY_MIN` | 10 | Default token expiry when `exp` is zero (minutes). |
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| `ECT_JTI_REPLAY_CACHE_SIZE` | 0 | Max JTIs to remember for replay check; 0 = disabled. |
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| `ECT_JTI_REPLAY_TTL_MIN` | 60 | TTL for JTI cache entries (minutes). |
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### Replay cache (multi-instance)
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`JTICache` is in-memory only. For multiple verifier instances (e.g. behind a load balancer), use a shared store (Redis, database) so every instance sees the same “seen” JTIs. Implement `JTISeen` as a function that checks (and optionally records) the JTI in that store (e.g. with TTL). Pass it in `VerifyOptions.JTISeen`. See refimpl/README for an overview.
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## Dependencies
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- [go-jose/v4](https://github.com/go-jose/go-jose/v4) for JWS (ES256) and JWK handling.
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## License
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Same as the Internet-Draft (IETF Trust). Code under Revised BSD per BCP 78/79.
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