4 Star 4 Fork 2

华为移动服务 / hms-nearby-contactshield-internals

加入 Gitee
与超过 1200万 开发者一起发现、参与优秀开源项目,私有仓库也完全免费 :)
免费加入
克隆/下载
贡献代码
同步代码
取消
提示: 由于 Git 不支持空文件夾,创建文件夹后会生成空的 .keep 文件
Loading...
README
Apache-2.0

华为接触卫士

English | 中文

简介

该项目是华为移动服务中接触卫士的代码片段,主要包括:密钥管理、蓝牙(BLE)任务管理、密钥文件分析、数据存储。本项目还提供了示例代码,为您展示如何在已集成Google Exposure Notification的应用中快速集成Contact Shield SDK。

密钥管理

本模块描述了如何生成周期性密钥、动态共享码(DSC)和辅助元数据(SD)。启动接触卫士服务(Contact Shield)时,调用ContactAdvBeaconGenerator.generate()可以生成上述与周期性密钥相关的数据。关键步骤如下:

  1. 获取当天的周期性密钥。注意每个应用都有自己的周期性密钥集合。调用PeriodicKeyGenerator.getPeriodicKey()以获取周期性密钥,其逻辑为:
  • 如果数据库中已有当天的周期性密钥,则调用该接口会立即返回此密钥。
  • 如果数据库中未保存当天的周期性密钥,该接口会调用PeriodicKeyGenerator.cRNG()生成一个新的随机数组作为密钥,并将其保存至数据库中,之后返回新生成的密钥。
  1. DSC的生成依赖DSC KeyPaddedData。DSC Key派生自周期性密钥,可通过调用DynamicSharingCode.getDscKey()生成。PaddedData包含了当前时间的Interval Number值,通过调用DynamicSharingCode.generatePaddedData()生成。当准备好DSC Key和PaddedData后,调用EncryptDecrypt.aesEcbEncrypt()使用DSC Key加密PaddedData,从而生成DSC。所以,DSC是加密后的PaddedData

  2. SD的生成需要使用到DSC(DSC生成请参考步骤2)、SD KeymetadataSupplementaryData类中的SupplementaryData.getSdKey()可用于生成SD Key。SD Key也是派生自周期性密钥,用于加密承载了BLE报文版本和传输功率的蓝牙metadata。具体实现细节请参见ContactAdvBeaconGenerator。最后,调用EncryptDecrypt.aesCtrEncrypt()生成新的SD。

蓝牙(BLE)任务管理

接触卫士使用BLE与其他设备进行数据交互,期间向周围广播和扫描DSC和SD。接触卫士将扫描端与广播端整合在一起,便于管理。ContactBeacon类承载了具体的广播报文。可以通过调用pack()unpack()方法来转换广播报文和ContactBeacon。调用ContactManage.startContact()后,接触卫士将进行如下操作:

  1. 检查蓝牙状态,确保您的设备支持BLE。如果当前蓝牙处于关闭状态,则打开蓝牙。

  2. 调用ContactBleScanner.startBleScan()启动BLE扫描,并配置BLE scanner timer,使扫描在4秒后停止。BLE扫描端的具体实现细节集中在ContactBleScanner类中。当接触卫士广播时,此类会调用ContactBeacon.unpack()并将新发现的ContactBeacon传给ContactManager。由ContactManager来保存ContactBeaconDSCSDRSSI

  3. 开始BLE广播。首先调用ContactAdvBeaconGenerator.generate()来生成ContactBeaconContactBeacon可以连结DSC数据(对应当前时间戳Interval Number的值)和SD数据(加密的蓝牙metadata)。然后将生成的ContactBeacon传入ContactBleAdvertiser.startBleAdv()。BLE广播端的实现细节集中在ContactBleAdvertiser类中。

  4. BLE scanner timer失效后,停止BLE扫描并调用ContactDataManage.flushScanDataToDb()将扫描到的所有数据从缓存写入数据库。然后配置Contact Shield alarm,以便在3-4分钟后开始下一次BLE扫描。

  5. 每次触发Contact Shield alarm时,按照上述启动BLE扫描端持续扫描4秒,同时Contact Shield将检查BLE广播端数据更新的时间戳。如果超过十分钟未更新广播数据,则重新启动BLE广播端以更新DSC/SD数据。

密钥文件分析

ContactAnalyze类实现了密钥文件分析的核心步骤。ContactAnalyze.analyzeKeyFileList()是诊断入口,调用该接口时,需要传入诊断配置信息(DiagnosisConfiguration的实例)来计算接触风险值。

当app传入压缩文件后,KeyFileParser.parseFiles()可以将每个密钥文件转换成相应的周期性密钥,并基于每个周期性密钥的有效时间和生存周期来判断它们的合法性,丢弃那些超过潜伏期的周期性密钥。

在诊断过程中,密钥管理模块可以协助ContactAnalyze.getTargetDsc()为每个潜伏期内的密钥生成所有DSC,称之为目标DSC集合(target DSCs),然后对比目标DSC集合和本地数据库保存的BLE曾扫描到的病毒潜伏期内的DSC数据表。

一旦任一本地DSC与目标DSC匹配,便可确认当前用户与确诊者曾经有过近距离接触。接触卫士会根据匹配到的DSC数量,通过具体的DiagnosisConfiguration计算风险值。与此同时,接触详情(Contact Detail)、接触摘要(Contact Sketch)和接触窗口(Contact Window)都会同步更新。

诊断结束后,有三种方法可以获取诊断结果:

  1. ContactAnalyze.getContactSketch() 提供传入的所有密钥压缩文件的摘要信息。
  2. ContactAnalyze.getDetailList() 提供密钥压缩文件中已匹配的密钥的详细信息。
  3. ContactAnalyze.getContactWindows() 提供ContactWindow模式下已匹配的密钥的详细信息。

诊断详情将保存至本地数据库以供后续查询,超过病毒潜伏期时将会被删除。

数据存储

本模块显示接触卫士会将哪些数据保存至数据库。底层数据库操作依赖于平台,此处不进行说明。以下是接触卫士工作时使用的主要数据:

类名 说明
ScanData BLE扫描数据,如DSC、SD、RSSI等。
PdkData 历史周期性密钥。
ContactDetailData 诊断结果:接触详情、token等。
ContactSketchData 诊断结果:接触摘要、token等。
ContactWindowData 诊断结果:接触窗口、ScanInfoData等。

何时清除数据:

  1. 当用户卸载接触卫士时,历史周期性密钥和诊断结果会被清除。
  2. 数据超过病毒潜伏期后,ContactDataManager.checkAndDeleteData()会删除历史周期性密钥、诊断结果和扫描数据。
  3. 用户可以在HMS Core Setting页删除历史周期性密钥和扫描数据。以EMUI为例:点击设置>应用管理>应用>HMS Core,然后点击右上角齿轮图标,选择COVID-19接触卫士>删除随机ID。

Contact Shield Wrapper

根据此模块的封装接口,可以轻松更新已集成Google Exposure Notification的应用来集成Contact Shield SDK。详情请参考ContactShieldWrapperReadme.

Copyright 2020 Huawei Technologies Co., Ltd Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. Apache License, Version 2.0 TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 1. Definitions. "License" shall mean the terms and conditions for use, reproduction, and distribution as defined by Sections 1 through 9 of this document. "Licensor" shall mean the copyright owner or entity authorized by the copyright owner that is granting the License. "Legal Entity" shall mean the union of the acting entity and all other entities that control, are controlled by, or are under common control with that entity. For the purposes of this definition, "control" means (i) the power, direct or indirect, to cause the direction or management of such entity, whether by contract or otherwise, or (ii) ownership of fifty percent (50%) or more of the outstanding shares, or (iii) beneficial ownership of such entity. "You" (or "Your") shall mean an individual or Legal Entity exercising permissions granted by this License. "Source" form shall mean the preferred form for making modifications, including but not limited to software source code, documentation source, and configuration files. "Object" form shall mean any form resulting from mechanical transformation or translation of a Source form, including but not limited to compiled object code, generated documentation, and conversions to other media types. "Work" shall mean the work of authorship, whether in Source or Object form, made available under the License, as indicated by a copyright notice that is included in or attached to the work (an example is provided in the Appendix below). "Derivative Works" shall mean any work, whether in Source or Object form, that is based on (or derived from) the Work and for which the editorial revisions, annotations, elaborations, or other modifications represent, as a whole, an original work of authorship. For the purposes of this License, Derivative Works shall not include works that remain separable from, or merely link (or bind by name) to the interfaces of, the Work and Derivative Works thereof. "Contribution" shall mean any work of authorship, including the original version of the Work and any modifications or additions to that Work or Derivative Works thereof, that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner. For the purposes of this definition, "submitted" means any form of electronic, verbal, or written communication sent to the Licensor or its representatives, including but not limited to communication on electronic mailing lists, source code control systems, and issue tracking systems that are managed by, or on behalf of, the Licensor for the purpose of discussing and improving the Work, but excluding communication that is conspicuously marked or otherwise designated in writing by the copyright owner as "Not a Contribution." "Contributor" shall mean Licensor and any individual or Legal Entity on behalf of whom a Contribution has been received by Licensor and subsequently incorporated within the Work. 2. Grant of Copyright License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare Derivative Works of, publicly display, publicly perform, sublicense, and distribute the Work and such Derivative Works in Source or Object form. 3. Grant of Patent License. Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer the Work, where such license applies only to those patent claims licensable by such Contributor that are necessarily infringed by their Contribution(s) alone or by combination of their Contribution(s) with the Work to which such Contribution(s) was submitted. If You institute patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that the Work or a Contribution incorporated within the Work constitutes direct or contributory patent infringement, then any patent licenses granted to You under this License for that Work shall terminate as of the date such litigation is filed. 4. Redistribution. You may reproduce and distribute copies of the Work or Derivative Works thereof in any medium, with or without modifications, and in Source or Object form, provided that You meet the following conditions: You must give any other recipients of the Work or Derivative Works a copy of this License; and You must cause any modified files to carry prominent notices stating that You changed the files; and You must retain, in the Source form of any Derivative Works that You distribute, all copyright, patent, trademark, and attribution notices from the Source form of the Work, excluding those notices that do not pertain to any part of the Derivative Works; and If the Work includes a "NOTICE" text file as part of its distribution, then any Derivative Works that You distribute must include a readable copy of the attribution notices contained within such NOTICE file, excluding those notices that do not pertain to any part of the Derivative Works, in at least one of the following places: within a NOTICE text file distributed as part of the Derivative Works; within the Source form or documentation, if provided along with the Derivative Works; or, within a display generated by the Derivative Works, if and wherever such third-party notices normally appear. The contents of the NOTICE file are for informational purposes only and do not modify the License. You may add Your own attribution notices within Derivative Works that You distribute, alongside or as an addendum to the NOTICE text from the Work, provided that such additional attribution notices cannot be construed as modifying the License. You may add Your own copyright statement to Your modifications and may provide additional or different license terms and conditions for use, reproduction, or distribution of Your modifications, or for any such Derivative Works as a whole, provided Your use, reproduction, and distribution of the Work otherwise complies with the conditions stated in this License. 5. Submission of Contributions. Unless You explicitly state otherwise, any Contribution intentionally submitted for inclusion in the Work by You to the Licensor shall be under the terms and conditions of this License, without any additional terms or conditions. Notwithstanding the above, nothing herein shall supersede or modify the terms of any separate license agreement you may have executed with Licensor regarding such Contributions. 6. Trademarks. This License does not grant permission to use the trade names, trademarks, service marks, or product names of the Licensor, except as required for reasonable and customary use in describing the origin of the Work and reproducing the content of the NOTICE file. 7. Disclaimer of Warranty. Unless required by applicable law or agreed to in writing, Licensor provides the Work (and each Contributor provides its Contributions) on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. You are solely responsible for determining the appropriateness of using or redistributing the Work and assume any risks associated with Your exercise of permissions under this License. 8. Limitation of Liability. In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall any Contributor be liable to You for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising as a result of this License or out of the use or inability to use the Work (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if such Contributor has been advised of the possibility of such damages. 9. Accepting Warranty or Additional Liability. While redistributing the Work or Derivative Works thereof, You may choose to offer, and charge a fee for, acceptance of support, warranty, indemnity, or other liability obligations and/or rights consistent with this License. However, in accepting such obligations, You may act only on Your own behalf and on Your sole responsibility, not on behalf of any other Contributor, and only if You agree to indemnify, defend, and hold each Contributor harmless for any liability incurred by, or claims asserted against, such Contributor by reason of your accepting any such warranty or additional liability. END OF TERMS AND CONDITIONS

简介

该项目是华为移动服务中接触卫士的代码片段,主要包括:密钥管理、蓝牙(BLE)任务管理、密钥文件分析、数据存储。本项目还提供了示例代码,为您展示如何在已集成Google Exposure Notification的应用中快速集成Contact Shield SDK。 展开 收起
Java
Apache-2.0
取消

发行版

暂无发行版

贡献者

全部

近期动态

加载更多
不能加载更多了
Java
1
https://gitee.com/hms-core/hms-nearby-contactshield-internals.git
git@gitee.com:hms-core/hms-nearby-contactshield-internals.git
hms-core
hms-nearby-contactshield-internals
hms-nearby-contactshield-internals
master

搜索帮助