98 lines
3.2 KiB
Markdown
98 lines
3.2 KiB
Markdown
+++
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title = "Chatto <A Self Hosted E2EE Chat Applicati>n"
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date = "2020-06-01T15:02:07+05:30"
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disable_comments = true
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draft = false
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[sidebar]
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disable = true
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categories = [
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"Projects"
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]
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tags = [
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"java",
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"spring-boot",
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"hibernate",
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"self-hosted",
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"e2ee",
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"encryption",
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"typescript"
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]
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[menu]
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[menu.main]
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parent = "Projects"
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name = "Chatto"
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+++
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Chatto is a self hosted, end to end encrypted chat application.
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[Repository](https://git.arcusiridis.com/nova/Chatto)
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[Documentation](https://git.arcusiridis.com/nova/Chatto/wiki)
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## Key Features
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1. Open Source, Self Hosted
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2. Messages are encrypted end to end using AES GCM encryption (paramters like keysize can be configured)
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3. No personal information such as names or email required
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4. Does not rely on any external services like auth services, mail servers or captcha services
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5. You are in control of your data.
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6. Backend exposes a JSON API that can be used by third party clients
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7. The chat messages support markdown
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## Technical Features
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1. Made with Java, Spring Boot and Hibernate
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2. Front end is made with Thymeleaf templates and uses AJAX(written in TypeScript) to provide dynamic functionality
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3. All password are stored hashed using Bcrypt
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4. Uses a custom token based authentication scheme making use of Spring Security. Tokens are cached using EhCache
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5. Care has been taken to safeguard against attacks like CSRF and XSS
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* Server side cookies are protected against CSRF using CSRF tokens
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* To protect the JSON API auth token against XSS, DomPurify is used to sanitize any user provided HTML
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* Server side DTO validation is used to sanitize user input
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## Tech Stack
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* **Backend** - Java, Spring Boot, Hibernate, Maven
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+ Database migrations using flyway
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* Caching using EhCache
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* **Frontend** -
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+ Server side templating - Thymeleaf
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+ JS - TypeScript, Browserify (and plugins like tsify), Terser, Grunt, Yarn
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* Templating using Handlebars
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## Preview
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### Design
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+ **Full layout**
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<p align="center"> 
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Design adapted from [bootsnip](https://bootsnipp.com/snippets/nNg98)</p>
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+ **Mobile layout** <br>
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The UI uses bootstrap grid system for a fully responsive layout. This is how it might look on a mobile screen -
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<p align="center"></p>
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<!-- <video autoplay loop style=" width: 100% !important;
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height: auto !important;">
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<source type="video/mp4" src="/img/projects/chatto/chatto-preview-infinite-scroll.mkv">
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</source>
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</video> -->
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### Infinite scroll
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{{< apvid >}}/img/projects/chatto/chatto-preview-infinite-scroll-2.webm{{< /apvid >}}
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Decryption takes place on the fly on a background thread using the web worker API for a smooth user experience.
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### E2EE Passphrase
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{{< avid >}}/img/projects/chatto/chatto-preview-passphrase.mp4{{</ avid>}}
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Note - passphrase is not stored on the server, or anywhere other than client's memory. The app simply checks whether decryption was successful to determine whether the passphrase is correct.
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### Markdown in chat
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{{< avid >}}/img/projects/chatto/chatto-preview-markdown.webm{{</ avid>}}
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