feat: implement KEncrypt for classical and post-quantum encryption methods

.devcontainer/devcontainer.json

@@ -1,13 +1,8 @@
 {
   "name": "Android Kotlin Dev Environment",
+  // Java 21 is already bundled in the base image — no need for the SDKMAN feature.
+  // Adding it again causes a conflict because SDKMAN can't locate "ms/21" in its registry.
   "image": "mcr.microsoft.com/devcontainers/java:1-21-bullseye",
-  "features": {
-    "ghcr.io/devcontainers/features/java:1": {
-      "version": "21",
-      "jdkDistribution": "ms",
-      "gradleVersion": "latest"
-    }
-  },
   "remoteEnv": {
     "ANDROID_HOME": "/usr/local/lib/android/sdk",
     "ANDROID_SDK_ROOT": "/usr/local/lib/android/sdk",

.devcontainer/post-create.sh

@@ -1,27 +1,62 @@
 #!/usr/bin/env bash
-set -e
+set -euo pipefail
 
-# Set target Android SDK directory
 SDK_DIR="/usr/local/lib/android/sdk"
+CMDLINE_VERSION="11076708"
+GRADLE_VERSION="8.7"
+
+echo "──────────────────────────────────────────"
+echo " Android SDK setup"
+echo "──────────────────────────────────────────"
+
+# ── 1. SDK directory ────────────────────────────────────────────────────────
 sudo mkdir -p "$SDK_DIR/cmdline-tools"
-sudo chown -R vscode:vscode "$SDK_DIR"
+sudo chown -R vscode:vscode /usr/local/lib/android
 
-# Download Android Command-Line Tools
-CMDLINE_VERSION="11076708" # Latest command-line tools version
+# ── 2. Command-line tools ───────────────────────────────────────────────────
+echo "→ Downloading Android cmdline-tools ${CMDLINE_VERSION}…"
 cd /tmp
-wget -q "https://dl.google.com/android/repository/commandlinetools-linux-${CMDLINE_VERSION}_latest.zip"
-unzip -q "commandlinetools-linux-${CMDLINE_VERSION}_latest.zip"
-
-# Move tools to the expected structure ($ANDROID_HOME/cmdline-tools/latest/bin)
+wget -q "https://dl.google.com/android/repository/commandlinetools-linux-${CMDLINE_VERSION}_latest.zip" \
+     -O cmdline-tools.zip
+unzip -q cmdline-tools.zip
 mkdir -p "$SDK_DIR/cmdline-tools/latest"
-mv cmdline-tools/* "$SDK_DIR/cmdline-tools/latest/" 2>/dev/null || true
-rm -rf "commandlinetools-linux-${CMDLINE_VERSION}_latest.zip" cmdline-tools
+mv cmdline-tools/* "$SDK_DIR/cmdline-tools/latest/"
+rm -rf cmdline-tools.zip cmdline-tools
+
+# ── 3. SDK packages ─────────────────────────────────────────────────────────
+SDKMANAGER="$SDK_DIR/cmdline-tools/latest/bin/sdkmanager"
+echo "→ Accepting licenses…"
+yes | "$SDKMANAGER" --licenses > /dev/null 2>&1 || true
+
+echo "→ Installing SDK packages…"
+"$SDKMANAGER" \
+  "platform-tools" \
+  "platforms;android-34" \
+  "build-tools;34.0.0"
+
+# ── 4. Gradle (standalone, no SDKMAN needed) ────────────────────────────────
+if ! command -v gradle &> /dev/null; then
+  echo "→ Installing Gradle ${GRADLE_VERSION}…"
+  cd /tmp
+  wget -q "https://services.gradle.org/distributions/gradle-${GRADLE_VERSION}-bin.zip" \
+       -O gradle.zip
+  sudo unzip -q gradle.zip -d /opt
+  sudo ln -sf "/opt/gradle-${GRADLE_VERSION}/bin/gradle" /usr/local/bin/gradle
+  rm gradle.zip
+  echo "   Gradle $(gradle --version | head -1) installed."
+else
+  echo "→ Gradle already available: $(gradle --version | head -1)"
+fi
 
-# Accept licenses & install platforms/build-tools
-yes | "$SDK_DIR/cmdline-tools/latest/bin/sdkmanager" --licenses
-"$SDK_DIR/cmdline-tools/latest/bin/sdkmanager" "platform-tools" "platforms;android-34" "build-tools;34.0.0"
+# ── 5. Gradle wrapper ───────────────────────────────────────────────────────
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+if [ -f "$SCRIPT_DIR/gradlew" ]; then
+  chmod +x "$SCRIPT_DIR/gradlew"
+  echo "→ gradlew made executable."
+fi
 
-# Make Gradle wrapper executable if present
-if [ -f "./gradlew" ]; then
-  chmod +x ./gradlew
-fi
+echo ""
+echo "✓ Android dev environment ready."
+echo "  Java   : $(java -version 2>&1 | head -1)"
+echo "  Gradle : $(gradle --version 2>/dev/null | head -1)"
+echo "  SDK    : $SDK_DIR"

buildSrc/src/main/kotlin/Versions.kt

@@ -13,7 +13,8 @@ object Versions {
     const val ktor                  = "2.3.12"
     const val coil                  = "3.5.0"
     const val serialization         = "1.6.3"
-    const val immutableCollections   = "0.3.8"
+    const val immutableCollections  = "0.3.8"
+    const val castle                = "1.80"
 
     // AndroidX / Google
     const val annotationJvm          = "1.10.0"

utils/build.gradle.kts

@@ -10,10 +10,13 @@ dependencies {
     implementation("androidx.annotation:annotation-jvm:1.10.0")
     implementation(kotlin("stdlib"))
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:${Versions.coroutines}")
+    implementation("org.jetbrains.kotlinx:kotlinx-datetime:0.6.0")
+    implementation("org.bouncycastle:bcpkix-jdk18on:${Versions.castle}")
+    implementation("org.bouncycastle:bcprov-jdk18on:${Versions.castle}")
+    implementation("org.bouncycastle:bcpqc-jdk18on:${Versions.castle}")
     testImplementation(kotlin("test"))
     testImplementation("org.junit.jupiter:junit-jupiter:${Versions.junit5}")
     testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:${Versions.coroutines}")
-    implementation("org.jetbrains.kotlinx:kotlinx-datetime:0.6.0")
 }
 
 tasks.test { useJUnitPlatform() }