From 37f1678940e3da329a019092a32b4db50ad79183 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E1=9E=87=E1=9E=B6=E1=9E=84=E1=9E=8C=E1=9E=B8=E1=9E=93=20?=
 =?UTF-8?q?=E1=9E=92=E1=9E=B8?=
 <316307659+dda994179-beep@users.noreply.github.com>
Date: Thu, 20 Aug 2026 04:23:37 +0700
Subject: [PATCH 1/2] docs: add DIT Racing 2.2 PIN Security architecture
 diagram

---
 DIT_RACING_2.2_PIN_SECURITY.md | 123 +++++++++++++++++++++++++++++++++
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 create mode 100644 DIT_RACING_2.2_PIN_SECURITY.md

diff --git a/DIT_RACING_2.2_PIN_SECURITY.md b/DIT_RACING_2.2_PIN_SECURITY.md
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+# DIT RACING 2.2 — PIN Security
+
+## User flow
+- First use: Settings → សុវត្ថិភាព → កំណត់ PIN.
+- On next app launch: PIN screen appears before protected content.
+- Settings can change or disable the PIN after current PIN verification.
+- Wrong PIN clears the field and shows an error.
+
+## Security
+The PIN is not stored as plain text; the app stores a SHA-256 digest.
+For stronger protection of sensitive stored data, Android recommends using
+the Android Keystore for encryption keys and cryptographic operations.
+
+## Architecture Overview
+
+```mermaid
+graph TD
+    User["👤 User"]
+    App["📱 DIT Racing App"]
+    
+    subgraph AppLayers["Application Layers"]
+        UI["UI Layer<br/>PIN Input Screen"]
+        Logic["Business Logic<br/>PIN Verification"]
+        Storage["Data Layer<br/>Local Storage"]
+    end
+    
+    subgraph Security["🔒 Security Layer"]
+        Hash["SHA-256<br/>Hashing"]
+        Keystore["Android Keystore<br/>Encryption Keys"]
+    end
+    
+    subgraph OnFirstLaunch["First Use Flow"]
+        Settings["Settings Page"]
+        Security_Menu["សុវត្ថិភាព Menu"]
+        SetPIN["កំណត់ PIN Dialog"]
+    end
+    
+    subgraph OnNextLaunch["Subsequent Launches"]
+        PINCheck["PIN Verification Screen"]
+        Validate["Validate against stored<br/>SHA-256 digest"]
+        ProtectedContent["Access Protected Content"]
+        Error["Show Error & Clear Field"]
+    end
+    
+    User -->|Opens App| App
+    App -->|First Time| OnFirstLaunch
+    Settings -->|Navigate| Security_Menu
+    Security_Menu -->|Select| SetPIN
+    SetPIN -->|User enters PIN| Hash
+    Hash -->|SHA-256 digest| Keystore
+    Keystore -->|Store encrypted| Storage
+    
+    App -->|Subsequent Launches| OnNextLaunch
+    PINCheck -->|User enters PIN| Validate
+    Validate -->|Match| ProtectedContent
+    Validate -->|No Match| Error
+    Error -->|Retry| PINCheck
+    
+    Validate -->|Request encryption key| Keystore
+    Storage -.->|Retrieve encrypted digest| Validate
+    
+    classDef security fill:#ff6b6b,stroke:#c92a2a,color:#fff
+    classDef ui fill:#4c6ef5,stroke:#364fc7,color:#fff
+    classDef storage fill:#ffd93d,stroke:#f59f00,color:#000
+    classDef flow fill:#51cf66,stroke:#2f9e44,color:#fff
+    
+    class Hash,Keystore security
+    class UI,PINCheck,Error ui
+    class Storage storage
+    class OnFirstLaunch,OnNextLaunch flow
+```
+
+## System Components
+
+### UI Layer
+- **PIN Input Screen**: Secure input field for PIN entry
+- **Settings Navigation**: Access security settings
+- **Error Display**: Show feedback for incorrect PIN attempts
+
+### Business Logic
+- **PIN Verification**: Compare user input against stored digest
+- **First-time Setup**: Initialize PIN on first launch
+- **Settings Management**: Change or disable PIN with verification
+
+### Data Layer
+- **Local Storage**: Persists encrypted PIN digest
+- **Encrypted State**: Protects sensitive configuration
+
+### Security Layer
+- **SHA-256 Hashing**: One-way cryptographic hash of PIN
+- **Android Keystore**: Stores and manages encryption keys securely
+  - Hardware-backed when available
+  - Prevents key extraction
+  - OS-level protection
+
+## Security Flow
+
+1. **Initial PIN Setup**
+   - User enters PIN in Settings → សុវត្ថិភាព → កំណត់ PIN
+   - PIN is hashed using SHA-256
+   - Hash is encrypted using Android Keystore
+   - Encrypted digest stored in local storage
+
+2. **PIN Verification on Launch**
+   - PIN screen appears before protected content
+   - User enters PIN
+   - Input is hashed with SHA-256
+   - Compare against stored encrypted digest
+   - Match → Grant access | No match → Clear field and show error
+
+3. **PIN Management**
+   - Changing PIN requires current PIN verification first
+   - Disabling PIN requires verification
+   - Updates re-hash and re-encrypt using Keystore
+
+## Best Practices Implemented
+
+✅ PIN stored as SHA-256 digest (not plaintext)  
+✅ Android Keystore for encryption key management  
+✅ Error feedback without exposing sensitive details  
+✅ Clear input field on failed attempts  
+✅ Secure on-launch verification  
+✅ Settings-based management with verification gate

From 74e35b7f652b9f0ed04f74bffca6a3e82cc441f6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E1=9E=87=E1=9E=B6=E1=9E=84=E1=9E=8C=E1=9E=B8=E1=9E=93=20?=
 =?UTF-8?q?=E1=9E=92=E1=9E=B8?=
 <316307659+dda994179-beep@users.noreply.github.com>
Date: Thu, 20 Aug 2026 05:28:24 +0700
Subject: [PATCH 2/2] Create Google
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

ហាងជួសជុលម៉ូតូ ឌីនធី 090833814 090804863
---
 Google | 1 +
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 create mode 100644 Google

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+