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check if messages contain known data DT-3038
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,11 @@ | ||
| /// Represents the level of trust in the authenticity of collected data. | ||
| enum DataAuthenticityStatus { | ||
| // verified by authority/multilateration | ||
| verified, | ||
| // default | ||
| untrusted, | ||
| // signs if questionable authenticity exist | ||
| suspicious, | ||
| // high certainty of falsehood | ||
| counterfeit | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,211 @@ | ||
| import 'package:dart_opendroneid/dart_opendroneid.dart'; | ||
| import 'package:flutter_opendroneid/models/constants.dart'; | ||
| import 'package:flutter_opendroneid/models/data_authenticity_status.dart'; | ||
| import 'package:flutter_opendroneid/models/message_container.dart'; | ||
|
|
||
| class MessageContainerAuthenticator { | ||
| /// Detectors that contribute to final score. | ||
| static final detectors = [ | ||
| MacAddressSpooferDetector(), | ||
| TimestampSpooferDetector(), | ||
| AuthDataSpooferDetector(), | ||
| BasicIdSpooferDetector(), | ||
| OperatorIdSpooferDetector(), | ||
| LocationSpooferDetector(), | ||
| SelfIdSpooferDetector(), | ||
| SystemDataSpooferDetector(), | ||
| ]; | ||
|
|
||
| /// Check contents of message container using [detectors]. | ||
| /// Test known spoofer data traits, each detector returns probability that | ||
| /// data were spoofed. Sum up the probablities and make final decision. | ||
| /// Convert score into [DataAuthenticityStatus] according to inverval: | ||
| /// < max/2 - untrusted | ||
| /// max/2, max/4*3 - suspicious | ||
| /// > max/4*3 - counterfeit. | ||
| static DataAuthenticityStatus determineAuthenticityStatus( | ||
| MessageContainer container) { | ||
| var score = 0.0; | ||
|
|
||
| detectors.forEach((element) { | ||
| score += element.calculateSpoofedProbability(container); | ||
| }); | ||
|
|
||
| return _scoreToStatus(score); | ||
| } | ||
|
|
||
| static DataAuthenticityStatus _scoreToStatus(double score) { | ||
| final maxScore = detectors.length; | ||
|
|
||
| // if nothing can be decided, score is exactly half, use as limi | ||
| final noSuspisionScore = maxScore * 0.5; | ||
| final counterfeitScore = maxScore * 0.75; | ||
|
|
||
| if (score <= noSuspisionScore) return DataAuthenticityStatus.untrusted; | ||
| if (score <= counterfeitScore) return DataAuthenticityStatus.suspicious; | ||
| return DataAuthenticityStatus.counterfeit; | ||
| } | ||
| } | ||
|
|
||
| abstract class SpooferDetector { | ||
| const SpooferDetector(); | ||
|
|
||
| /// Return a probability that data are spoofed. | ||
| /// 0 -> data are real | ||
| /// 0.5 -> cannot decide | ||
| /// 1 -> data are counterfeit | ||
| double calculateSpoofedProbability(MessageContainer container); | ||
| } | ||
|
|
||
| class MacAddressSpooferDetector implements SpooferDetector { | ||
| // spoofed data MAC addr always starts with a zero | ||
| // if starts with 0, still does'nt have to be spoofed | ||
| @override | ||
| double calculateSpoofedProbability(MessageContainer container) => | ||
| container.macAddress.startsWith('0') ? 0.75 : 0; | ||
| } | ||
|
|
||
| /// Spoofer starts counting time from known timestamp. | ||
| /// If received timestamp is in short interval after that timestamp, | ||
| /// data are probably spoofed. | ||
| class TimestampSpooferDetector implements SpooferDetector { | ||
| static final spooferTimestamp = DateTime(2022, 11, 16, 10); | ||
| static const maxUptime = Duration(days: 10); | ||
|
|
||
| bool _isNearSpooferTimestamp(DateTime timestamp) => | ||
| timestamp.isAfter(spooferTimestamp) && | ||
| timestamp.isBefore(spooferTimestamp.add(maxUptime)); | ||
|
|
||
| // returns true if any of timestamps within the interval | ||
| // (spooferTimestamp, spooferTimestamp + maxUptime). | ||
| @override | ||
| double calculateSpoofedProbability(MessageContainer container) { | ||
| final authTimestamp = container.authenticationMessage?.timestamp; | ||
| final systemTimestamp = container.systemDataMessage?.timestamp; | ||
|
|
||
| if (authTimestamp == null && systemTimestamp == null) return 0.5; | ||
|
|
||
| return (authTimestamp != null && _isNearSpooferTimestamp(authTimestamp)) || | ||
| systemTimestamp != null && _isNearSpooferTimestamp(systemTimestamp) | ||
| ? 1 | ||
| : 0; | ||
| } | ||
| } | ||
|
|
||
| /// Following detectors check the contents of messages and compare them with | ||
| /// known values for spoofed data. | ||
| class AuthDataSpooferDetector implements SpooferDetector { | ||
| @override | ||
| double calculateSpoofedProbability(MessageContainer container) { | ||
| final message = container.authenticationMessage; | ||
| // message not received, cannot decide | ||
| if (message == null) return 0.5; | ||
|
|
||
| // if len and type are not as expected, data are not spoofed | ||
| if (message.authData.authData.length != maxAuthDataPages || | ||
| message.authType != AuthType.none) return 0.1; | ||
|
|
||
| // spoofed auth data contain indexes | ||
| for (var index = 0; index < message.authData.authData.length; index++) { | ||
| if (message.authData.authData[index] != index) return 0.2; | ||
| } | ||
| return 0.8; | ||
| } | ||
| } | ||
|
|
||
| class BasicIdSpooferDetector implements SpooferDetector { | ||
| @override | ||
| double calculateSpoofedProbability(MessageContainer container) { | ||
| final messages = container.basicIdMessages; | ||
|
|
||
| if (messages == null || messages.isEmpty) return 0.5; | ||
|
|
||
| // spofed data always have 1 basic id with types set to .none | ||
| return (messages.length == 1 && | ||
| messages.values.first.uaType == UAType.none && | ||
| messages.values.first.uasID.type == IDType.none) | ||
| ? 0.8 | ||
| : 0.2; | ||
| } | ||
| } | ||
|
|
||
| class OperatorIdSpooferDetector implements SpooferDetector { | ||
| @override | ||
| double calculateSpoofedProbability(MessageContainer container) { | ||
| final message = container.operatorIdMessage; | ||
| // message not received, cannot decide | ||
| if (message == null) return 0.5; | ||
|
|
||
| // spofed DATA have 16 random chars in Operator IDm | ||
| // [OperatorIDTypeOperatorID] type and len 16 | ||
| if (message.operatorIDType is! OperatorIDTypeOperatorID || | ||
| message.operatorID.length != 16) return 0.3; | ||
| // check that country code cantains only capital letters | ||
| // if not, data are spoofed | ||
| final countryCode = message.operatorID.substring(0, 3); | ||
| if (countryCode != countryCode.toUpperCase()) return 0.9; | ||
| // country code contains capital letters, | ||
| // data can still be spoofed | ||
| return 0.4; | ||
| } | ||
| } | ||
|
|
||
| class LocationSpooferDetector implements SpooferDetector { | ||
| @override | ||
| double calculateSpoofedProbability(MessageContainer container) { | ||
| final message = container.locationMessage; | ||
| // message not received, cannot decide | ||
| if (message == null) return 0.5; | ||
|
|
||
| // spoofed if all values are set as expected | ||
| final spoofed = message.status == OperationalStatus.none && | ||
| (message.verticalSpeed == null || | ||
| message.verticalSpeed == INV_SPEED_V) && | ||
| message.heightType == HeightType.aboveTakeoff && | ||
| message.horizontalAccuracy == HorizontalAccuracy.meters_10 && | ||
| message.verticalAccuracy == VerticalAccuracy.meters_10 && | ||
| message.baroAltitudeAccuracy == VerticalAccuracy.meters_10 && | ||
| message.speedAccuracy == SpeedAccuracy.meterPerSecond_10 && | ||
| // spoofed data have acc 1.5 | ||
| message.timestampAccuracy?.compareTo(Duration(milliseconds: 1500)) == 0; | ||
| return spoofed ? 1 : 0.2; | ||
| } | ||
| } | ||
|
|
||
| class SelfIdSpooferDetector implements SpooferDetector { | ||
| @override | ||
| double calculateSpoofedProbability(MessageContainer container) { | ||
| final message = container.selfIdMessage; | ||
| // message not received, cannot decide | ||
| if (message == null) return 0.5; | ||
|
|
||
| // spoofed if all values are set as expected | ||
| return message.descriptionType is DescriptionTypeText && | ||
| message.description == "Recreational" | ||
| ? 1 | ||
| : 0.2; | ||
| } | ||
| } | ||
|
|
||
| class SystemDataSpooferDetector implements SpooferDetector { | ||
| @override | ||
| double calculateSpoofedProbability(MessageContainer container) { | ||
| final message = container.systemDataMessage; | ||
| // message not received, cannot decide | ||
| if (message == null) return 0.5; | ||
|
|
||
| // spoofed if all values are set as expected | ||
| final spoofed = message.operatorLocationType == | ||
| OperatorLocationType.takeOff && | ||
| message.uaClassification is UAClassificationEurope && | ||
| (message.uaClassification as UAClassificationEurope).uaCategoryEurope == | ||
| UACategoryEurope.EUOpen && | ||
| (message.uaClassification as UAClassificationEurope).uaClassEurope == | ||
| UAClassEurope.EUClass_4 && | ||
| message.areaCount == 1 && | ||
| message.areaRadius == 500 && | ||
| message.areaCeiling == null && | ||
| message.areaFloor == null; | ||
| return spoofed ? 1 : 0.2; | ||
| } | ||
| } |