feat: enhanced generateRandomizedSpec() with randomized keyShare and curveIDs

Author: nihiloid

u_common.go

@@ -684,6 +684,7 @@ type Weights struct {
 	Extensions_Append_Reneg                            float64
 	Extensions_Append_EMS                              float64
 	FirstKeyShare_Set_CurveP256                        float64
+	KeyShare_Append_RandomGroups                       float64
 	Extensions_Append_ALPS                             float64
 }
 
@@ -704,7 +705,8 @@ var DefaultWeights = Weights{
 	Extensions_Append_SCT:                              0.46,
 	Extensions_Append_Reneg:                            0.75,
 	Extensions_Append_EMS:                              0.77,
-	FirstKeyShare_Set_CurveP256:                        0.25,
+	FirstKeyShare_Set_CurveP256:                        0.00, // legacy setting
+	KeyShare_Append_RandomGroups:                       0.50,
 	Extensions_Append_ALPS:                             0.33,
 }
 

u_parrots.go

@@ -3053,6 +3053,9 @@ func generateRandomizedSpec(
 	points := SupportedPointsExtension{SupportedPoints: []byte{pointFormatUncompressed}}
 
 	curveIDs := []CurveID{}
+	if r.FlipWeightedCoin(id.Weights.CurveIDs_Append_X25519) && p.TLSVersMax == VersionTLS13 {
+		curveIDs = append(curveIDs, X25519MLKEM768)
+	}
 	if r.FlipWeightedCoin(id.Weights.CurveIDs_Append_X25519) || p.TLSVersMax == VersionTLS13 {
 		curveIDs = append(curveIDs, X25519)
 	}
@@ -3104,11 +3107,15 @@ func generateRandomizedSpec(
 		ks := KeyShareExtension{[]KeyShare{
 			{Group: X25519}, // the key for the group will be generated later
 		}}
-		if r.FlipWeightedCoin(id.Weights.FirstKeyShare_Set_CurveP256) {
-			// do not ADD second keyShare because crypto/tls does not support multiple ecdheParams
-			// TODO: add it back when they implement multiple keyShares, or implement it oursevles
-			// ks.KeyShares = append(ks.KeyShares, KeyShare{Group: CurveP256})
+		if r.FlipWeightedCoin(id.Weights.FirstKeyShare_Set_CurveP256) { // legacy setting, not used by default
 			ks.KeyShares[0].Group = CurveP256
+		} else {
+			if r.FlipWeightedCoin(id.Weights.KeyShare_Append_RandomGroups) {
+				ks.KeyShares = append(ks.KeyShares, KeyShare{Group: CurveP256})
+			}
+			if r.FlipWeightedCoin(id.Weights.KeyShare_Append_RandomGroups) {
+				ks.KeyShares = append([]KeyShare{{Group: X25519MLKEM768}}, ks.KeyShares...)
+			}
 		}
 		pskExchangeModes := PSKKeyExchangeModesExtension{[]uint8{pskModeDHE}}
 		supportedVersionsExt := SupportedVersionsExtension{