diff --git a/cmd/server/main_test.go b/cmd/server/main_test.go
index f39a216..04e0346 100644
--- a/cmd/server/main_test.go
+++ b/cmd/server/main_test.go
@@ -44,9 +44,8 @@ func TestMain_HealthEndpointBypassesAuth(t *testing.T) {
 	})
 
 	// Build the handler chain the same way main.go does
-	authMiddleware := middleware.NewAuth(middleware.AuthConfig{
-		Type:   "api-key",
-		Secret: "test-secret-key",
+	authMiddleware := middleware.NewAuthWithNamedKeys([]middleware.NamedAPIKey{
+		{Name: "test", Key: "test-secret-key"},
 	})
 
 	// API handler with auth
@@ -160,9 +159,8 @@ func TestMain_AuthMiddlewareRejectsUnauthorized(t *testing.T) {
 	})
 
 	// Wrap with auth middleware
-	authMiddleware := middleware.NewAuth(middleware.AuthConfig{
-		Type:   "api-key",
-		Secret: "test-secret-key",
+	authMiddleware := middleware.NewAuthWithNamedKeys([]middleware.NamedAPIKey{
+		{Name: "test", Key: "test-secret-key"},
 	})
 
 	chainedHandler := middleware.Chain(protectedHandler, authMiddleware)
@@ -189,9 +187,8 @@ func TestMain_AuthMiddlewareAllowsWithValidKey(t *testing.T) {
 	})
 
 	// Wrap with auth middleware
-	authMiddleware := middleware.NewAuth(middleware.AuthConfig{
-		Type:   "api-key",
-		Secret: testKey,
+	authMiddleware := middleware.NewAuthWithNamedKeys([]middleware.NamedAPIKey{
+		{Name: "test", Key: testKey},
 	})
 
 	chainedHandler := middleware.Chain(protectedHandler, authMiddleware)
@@ -462,9 +459,8 @@ func TestMain_AuthNoneMode(t *testing.T) {
 	})
 
 	// Wrap with auth middleware in "none" mode
-	authMiddleware := middleware.NewAuth(middleware.AuthConfig{
-		Type: "none",
-	})
+	// auth=none equivalent: empty named-keys list is a no-op pass-through.
+	authMiddleware := middleware.NewAuthWithNamedKeys(nil)
 
 	chainedHandler := middleware.Chain(protectedHandler, authMiddleware)
 
diff --git a/docs/features.md b/docs/features.md
index 39f06dd..7c83f49 100644
--- a/docs/features.md
+++ b/docs/features.md
@@ -60,11 +60,20 @@ Two endpoints are served without auth so the GUI can detect auth mode before log
 
 Token bucket algorithm protecting the control plane from misbehaving clients.
 
+Bundle B (Audit M-025 / OWASP ASVS L2 §11.2.1): per-key keying. Each
+authenticated caller gets a bucket keyed on their API-key name; each
+unauthenticated source IP gets its own bucket. Bucket creation is
+on-demand under a `sync.RWMutex`; no eviction (the leak is bounded by
+realistic operator IP fan-out — appropriate for the OWASP ASVS L2 threat
+model of abuse-by-known-clients, not infinite-cardinality scanners).
+
 | Env Var | Default | Description |
 |---|---|---|
 | `CERTCTL_RATE_LIMIT_ENABLED` | `true` | Enable/disable |
-| `CERTCTL_RATE_LIMIT_RPS` | `50` | Requests per second |
-| `CERTCTL_RATE_LIMIT_BURST` | `100` | Burst capacity |
+| `CERTCTL_RATE_LIMIT_RPS` | `50` | Per-key requests per second (default applies to IP-keyed buckets; user-keyed buckets fall back to this when `PER_USER_RPS` is unset) |
+| `CERTCTL_RATE_LIMIT_BURST` | `100` | Per-key burst capacity (default applies to IP-keyed buckets; user-keyed buckets fall back to this when `PER_USER_BURST` is unset) |
+| `CERTCTL_RATE_LIMIT_PER_USER_RPS` | `0` | Override RPS for authenticated callers. `0` means "use `RATE_LIMIT_RPS`". Set higher than `RATE_LIMIT_RPS` to grant authenticated clients a more generous budget than anonymous probes. |
+| `CERTCTL_RATE_LIMIT_PER_USER_BURST` | `0` | Override burst for authenticated callers. `0` means "use `RATE_LIMIT_BURST`". |
 
 Exceeded requests receive `429 Too Many Requests` with a `Retry-After` header.
 
diff --git a/internal/api/handler/scep.go b/internal/api/handler/scep.go
index da91ede..7fb5e03 100644
--- a/internal/api/handler/scep.go
+++ b/internal/api/handler/scep.go
@@ -263,6 +263,18 @@ func extractCSRFields(csrDER []byte) ([]byte, string, string, error) {
 	// Attributes is []pkix.AttributeTypeAndValueSET where each has Type (OID)
 	// and Value ([][]pkix.AttributeTypeAndValue). The challenge password value
 	// is stored as a string in the inner AttributeTypeAndValue.Value field.
+	//
+	// Audit M-028 carve-out: Go's stdlib deprecates `csr.Attributes` for the
+	// specific use case of parsing the "requestedExtensions" CSR attribute
+	// (OID 1.2.840.113549.1.9.14), pointing callers at `csr.Extensions` /
+	// `csr.ExtraExtensions`. challengePassword (OID 1.2.840.113549.1.9.7)
+	// per RFC 2985 §5.4.1 is a SEPARATE CSR attribute that cannot be
+	// retrieved via Extensions. There is no non-deprecated stdlib API for
+	// it; callers either accept the deprecation warning or parse the raw
+	// `csr.RawAttributes` ASN.1 themselves. We accept the warning; the
+	// staticcheck.conf and golangci-lint rules suppress SA1019 for this
+	// specific line per the audit closure note.
+	//lint:ignore SA1019 RFC 2985 challengePassword has no non-deprecated stdlib API; see comment above.
 	for _, attr := range csr.Attributes {
 		if attr.Type.Equal(oidChallengePassword) {
 			if len(attr.Value) > 0 && len(attr.Value[0]) > 0 {
diff --git a/internal/connector/issuer/local/bundle9_coverage_test.go b/internal/connector/issuer/local/bundle9_coverage_test.go
index 7f3bed0..22b29e9 100644
--- a/internal/connector/issuer/local/bundle9_coverage_test.go
+++ b/internal/connector/issuer/local/bundle9_coverage_test.go
@@ -334,11 +334,12 @@ func TestHashPublicKey_ECDSA_RoundTripPin(t *testing.T) {
 				t.Fatalf("ecdsaToECDH: %v", err)
 			}
 			ecdhBytes := ecdhPub.Bytes()
-			//nolint:staticcheck // SA1019: pin assertion — we DELIBERATELY use
-			// the deprecated API here as a regression oracle to prove the
-			// new crypto/ecdh path produces byte-identical output. If
-			// elliptic.Marshal is removed in a future Go release this test
-			// must be deleted (and the migration is then irreversibly proven).
+			// Pin assertion — we DELIBERATELY use the deprecated API here
+			// as a regression oracle to prove the new crypto/ecdh path
+			// produces byte-identical output. If elliptic.Marshal is
+			// removed in a future Go release this test must be deleted
+			// (and the migration is then irreversibly proven).
+			//lint:ignore SA1019 deliberate regression oracle for M-028 round-trip pin
 			legacy := elliptic.Marshal(k.Curve, k.X, k.Y)
 			if !bytes.Equal(ecdhBytes, legacy) {
 				t.Fatalf("ECDH .Bytes() != legacy elliptic.Marshal output\n new: %x\n old: %x", ecdhBytes, legacy)