diff --git a/.gitignore b/.gitignore
index 06a4b4bfe..4d591b4b4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -88,4 +88,5 @@ fix_*.py
 rpms/
 deb_stage
 packages-out
+external-dependencies/offline-cache/
 
diff --git a/external-dependencies/offline-cache/README.md b/external-dependencies/offline-cache/README.md
new file mode 100644
index 000000000..b6e2e13d5
--- /dev/null
+++ b/external-dependencies/offline-cache/README.md
@@ -0,0 +1,238 @@
+# Offline Package Cache for Air-Gapped Environment
+
+> **Important:** This directory is excluded from version control (`.gitignore`). The offline cache must be built separately on a machine with internet access, then transferred to the air-gapped environment via secure media or artifact repository.
+
+This directory contains all external dependencies required for building the Legatus project in an air-gapped (offline) environment.
+
+## Directory Structure
+
+```
+offline-cache/
+├── qt6/                    # Qt 6.10.2 installation (2.2GB, 12,320 files)
+│   └── 6.10.2/
+│       └── gcc_64/
+│           └── lib/cmake/Qt6/
+│
+├── src/                    # Source tarballs for custom builds
+│   ├── KDReports-2.3.0.tar.gz      (8.3MB)
+│   ├── Log4Qt-2.0.0.tar.gz         (1.0MB)
+│   └── grantlee-20d415b.tar.gz     (2.5MB)
+│
+├── deb/                    # Ubuntu 26.04 development packages (49 packages, 51MB)
+│   ├── build-essential_*.deb
+│   ├── cmake_*.deb
+│   ├── libqt6*.deb
+│   ├── libboost-dev_*.deb
+│   ├── libssl-dev_*.deb
+│   └── ... (46 more)
+│
+├── scripts/                # Offline installation scripts
+│   ├── install-offline.sh  # Main installation script
+│   └── package-list.txt    # Complete package inventory
+│
+└── README.md               # This file
+```
+
+## Contents Summary
+
+| Component | Size | Files | Description |
+|-----------|------|-------|-------------|
+| Qt 6.10.2 | 2.2GB | 12,320 | Complete Qt installation (gcc_64) |
+| Source Tarballs | 12MB | 3 | KDReports, Log4Qt, Grantlee |
+| Ubuntu .deb | 51MB | 49 | Development packages |
+| **Total** | **2.3GB** | **12,372** | Complete offline cache |
+
+## Usage in Air-Gapped Environment
+
+### 1. Copy to Air-Gapped System
+
+Transfer the entire `offline-cache/` directory to your air-gapped build system:
+
+```bash
+# On connected system
+tar -czf offline-cache.tar.gz offline-cache/
+
+# Transfer via secure medium (USB, secure transfer, etc.)
+
+# On air-gapped system
+tar -xzf offline-cache.tar.gz
+```
+
+### 2. Install Qt 6.10.2
+
+```bash
+# Copy Qt installation to target location
+cp -r offline-cache/qt6/6.10.2 /opt/Qt/
+
+# Set environment variables
+export Qt6_DIR=/opt/Qt/6.10.2/gcc_64
+export PATH=$Qt6_DIR/bin:$PATH
+```
+
+### 3. Install Ubuntu Development Packages
+
+```bash
+# Install all .deb packages
+cd offline-cache/deb
+sudo dpkg -i *.deb
+
+# Or use apt with local repository
+cd offline-cache/deb
+sudo apt install ./*.deb
+```
+
+### 4. Build Custom Dependencies
+
+```bash
+# KDReports
+cd /tmp
+tar -xzf offline-cache/src/KDReports-2.3.0.tar.gz
+cd KDReports-2.3.0
+mkdir build && cd build
+cmake -DCMAKE_PREFIX_PATH=/opt/Qt/6.10.2/gcc_64 ..
+make -j8
+sudo make install
+
+# Log4Qt
+cd /tmp
+tar -xzf offline-cache/src/Log4Qt-2.0.0.tar.gz
+cd Log4Qt-2.0.0
+mkdir build && cd build
+cmake -DCMAKE_PREFIX_PATH=/opt/Qt/6.10.2/gcc_64 ..
+make -j8
+sudo make install
+
+# Grantlee
+cd /tmp
+tar -xzf offline-cache/src/grantlee-20d415b.tar.gz
+cd grantlee-20d415b
+mkdir build && cd build
+cmake -DGRANTLEE_BUILD_WITH_QT6=ON -DCMAKE_PREFIX_PATH=/opt/Qt/6.10.2/gcc_64 ..
+make -j8
+sudo make install
+```
+
+### 5. Verify Installation
+
+```bash
+# Check Qt version
+qmake6 --version
+
+# Check CMake
+cmake --version
+
+# Check compilers
+g++ --version
+clang++ --version
+```
+
+## Package Inventory
+
+### Qt Components (6.10.2)
+- Qt Base (Core, Gui, Widgets, Network, etc.)
+- Qt SVG
+- Qt Concurrent
+- Qt Test
+- Qt Linguist Tools
+
+### Ubuntu Development Packages (49 total)
+- **Build Tools:** build-essential, cmake, clang, gcc, g++
+- **Qt6 Libraries:** libqt6core6, libqt6gui6, libqt6widgets6, libqt6svg6, etc.
+- **Development Headers:** libqt6-dev, libqt6svg6-dev, libkf6texttemplate-dev
+- **Database:** libpq-dev, postgresql-server-dev-all
+- **Testing:** libgtest-dev, libgmock-dev
+- **Security:** libssl-dev, libbotan-3-dev
+- **Multimedia:** libvlc-dev, vlc-plugin-base
+- **Other:** libboost-dev, libgeographiclib-dev, libpoppler-qt6-dev, libxml2-dev, libicu-dev
+
+### Source Tarballs
+- **KDReports 2.3.0:** Report generation library
+- **Log4Qt 2.0.0:** Logging framework
+- **Grantlee (20d415b):** String template library
+
+## Jenkins Integration
+
+The offline cache is used by Jenkins pipelines in air-gapped environments:
+
+```groovy
+// In Jenkinsfile
+stage('Setup Offline Dependencies') {
+    steps {
+        script {
+            // Copy offline cache to build workspace
+            sh 'cp -r /path/to/offline-cache ${WORKSPACE}/'
+            
+            // Install Qt
+            sh 'cp -r ${WORKSPACE}/offline-cache/qt6/6.10.2 /opt/Qt/'
+            
+            // Install .deb packages
+            sh 'cd ${WORKSPACE}/offline-cache/deb && sudo dpkg -i *.deb'
+            
+            // Build custom dependencies
+            sh 'bash ${WORKSPACE}/offline-cache/scripts/install-offline.sh'
+        }
+    }
+}
+```
+
+## Maintenance
+
+### Updating Dependencies
+
+To update the offline cache:
+
+1. Run the download script on a connected system:
+   ```bash
+   cd external-dependencies
+   bash scripts/download-all-dependencies.sh ./offline-cache
+   ```
+
+2. Verify the downloaded packages:
+   ```bash
+   bash scripts/verify-offline-cache.sh ./offline-cache
+   ```
+
+3. Transfer to air-gapped system
+
+### Verification Checklist
+
+- [ ] Qt 6.10.2 installation complete (12,320+ files)
+- [ ] All source tarballs present (KDReports, Log4Qt, Grantlee)
+- [ ] All 49 .deb packages downloaded
+- [ ] Package list matches inventory
+- [ ] Installation scripts tested
+
+## Troubleshooting
+
+### Qt Installation Issues
+- Ensure correct architecture (gcc_64 for x86_64)
+- Check CMAKE_PREFIX_PATH includes Qt directory
+- Verify Qt6_DIR environment variable
+
+### Package Installation Issues
+- Check Ubuntu version matches (26.04)
+- Ensure all dependencies are satisfied
+- Use `dpkg --configure -a` to fix broken installs
+
+### Build Issues
+- Verify all custom dependencies are installed
+- Check CMake can find Qt6 components
+- Ensure compiler toolchain is complete
+
+## License Compliance
+
+All packages include their respective licenses:
+- Qt 6.10.2: LGPL v3 / Commercial
+- KDReports: Apache 2.0
+- Log4Qt: Apache 2.0
+- Grantlee: BSD 2-Clause
+- Ubuntu packages: Various (see individual .deb files)
+
+SBOM (Software Bill of Materials) is generated by the CI/CD pipeline using `generate-sbom.sh`.
+
+## Contact
+
+For questions or issues with the offline cache, refer to:
+- `external-dependencies/DEPENDENCIES-INVENTORY.md` - Complete dependency list
+- `external-dependencies/AIRGAP-SUMMARY.md` - Air-gap configuration
+- Jenkins pipeline documentation
\ No newline at end of file
diff --git a/external-dependencies/scripts/download-all-dependencies.sh b/external-dependencies/scripts/download-all-dependencies.sh
new file mode 100755
index 000000000..ffba3e87f
--- /dev/null
+++ b/external-dependencies/scripts/download-all-dependencies.sh
@@ -0,0 +1,118 @@
+#!/bin/bash
+#
+# Download all external dependencies for air-gapped environment
+# Creates offline package cache for Jenkins/Dockerfile use
+#
+# Usage: ./download-all-dependencies.sh [output-directory]
+#
+# Output directory structure:
+#   offline-cache/
+#   ├── qt6/                    # Qt6 packages from aqtinstall
+#   ├── src/                    # Source tarballs (KDReports, Log4Qt, Grantlee)
+#   ├── deb/                    # Ubuntu .deb packages
+#   └── scripts/                # Installation scripts for offline use
+#
+
+set -euo pipefail
+
+# Configuration
+OUTPUT_DIR="${1:-./offline-cache}"
+QT_VERSION="6.10.2"
+QT_MODULES="qtmultimedia qtserialport qtimageformats qtwebsockets qtwebengine qtpdf qtwebview qt5compat qtwebchannel qtpositioning qtlocation qtsensors"
+
+# Air-gapped environment configuration (from Dockerfiles)
+NEXUS_REPO="http://remote-repo.sl.defence-elec.de:8081"
+PIP_INDEX_URL="${NEXUS_REPO}/repository/proxypipy/"
+APT_SOURCES="${NEXUS_REPO}/repository/ubuntu"
+
+echo "========================================="
+echo "Downloading External Dependencies"
+echo "========================================="
+echo "Output directory: ${OUTPUT_DIR}"
+echo "Qt Version: ${QT_VERSION}"
+echo "========================================="
+
+# Create directory structure
+mkdir -p "${OUTPUT_DIR}"/{qt6,src,deb,scripts}
+
+# Run download in Docker container with proper environment
+echo ""
+echo "Running download in Ubuntu 26.04 Docker container..."
+echo ""
+
+docker run --rm \
+    -v "$(pwd)/${OUTPUT_DIR}:/cache" \
+    -e PIP_INDEX_URL="${PIP_INDEX_URL}" \
+    -e NEXUS_REPO="${NEXUS_REPO}" \
+    ubuntu:26.04 \
+    bash -c "
+set -euo pipefail
+
+OUTPUT_DIR='/cache'
+QT_VERSION='${QT_VERSION}'
+QT_MODULES='${QT_MODULES}'
+NEXUS_REPO='${NEXUS_REPO}'
+PIP_INDEX_URL='${PIP_INDEX_URL}'
+
+echo '=== Installing required packages ==='
+apt-get update -qq
+apt-get install -y -qq python3 python3-venv python3-pip git wget curl apt-transport-https
+
+echo ''
+echo '=== Setting up Python virtual environment for aqtinstall ==='
+python3 -m venv /tmp/aqtinstall_venv
+source /tmp/aqtinstall_venv/bin/activate
+
+# Install aqtinstall from standard PyPI (not available in internal proxy)
+echo 'Installing aqtinstall from standard PyPI...'
+pip install --quiet --index-url https://pypi.org/simple aqtinstall
+
+echo ''
+echo '=== Downloading Qt6 \${QT_VERSION} ==='
+aqt install-qt linux desktop \${QT_VERSION} linux_gcc_64 \\
+    --modules \${QT_MODULES} \\
+    --outputdir /cache/qt6 \\
+    --base \${NEXUS_REPO}/repository/qt-mirror/
+
+echo ''
+echo 'Qt6 downloaded to /cache/qt6'
+
+echo ''
+echo '=== Downloading Source Tarballs ==='
+
+# KDReports
+echo 'Downloading KDReports 2.3.0...'
+git clone --depth 1 --branch kdreports-2.3.0 \\
+    https://github.com/KDAB/KDReports.git \\
+    /tmp/KDReports
+tar -czf /cache/src/KDReports-2.3.0.tar.gz -C /tmp KDReports
+rm -rf /tmp/KDReports
+
+# Log4Qt
+echo 'Downloading Log4Qt 2.0.0...'
+git clone --depth 1 --branch v2.0.0 \\
+    https://github.com/MEONMedical/Log4Qt.git \\
+    /tmp/Log4Qt
+tar -czf /cache/src/Log4Qt-2.0.0.tar.gz -C /tmp Log4Qt
+rm -rf /tmp/Log4Qt
+
+# Grantlee
+echo 'Downloading Grantlee (master branch)...'
+git clone --depth 1 \\
+    https://github.com/steveire/grantlee.git \\
+    /tmp/grantlee
+GRANTLEE_COMMIT=\$(cd /tmp/grantlee && git rev-parse HEAD)
+echo 'Grantlee commit: \${GRANTLEE_COMMIT}'
+tar -czf /cache/src/grantlee-\${GRANTLEE_COMMIT:0:7}.tar.gz -C /tmp grantlee
+rm -rf /tmp/grantlee
+
+echo ''
+echo 'Source tarballs downloaded to /cache/src'
+
+# Cleanup
+deactivate 2>/dev/null || true
+rm -rf /tmp/aqtinstall_venv
+
+echo ''
+echo '=== Download Complete ==='
+"
\ No newline at end of file
diff --git a/external-dependencies/scripts/download-deb-packages.sh b/external-dependencies/scripts/download-deb-packages.sh
new file mode 100755
index 000000000..4c9064b95
--- /dev/null
+++ b/external-dependencies/scripts/download-deb-packages.sh
@@ -0,0 +1,137 @@
+#!/bin/bash
+#
+# Download Ubuntu .deb packages for offline use
+# Run this script inside Ubuntu 26.04 container
+#
+# Usage: ./download-deb-packages.sh [output-directory]
+#
+
+set -euo pipefail
+
+OUTPUT_DIR="${1:-./offline-cache/deb}"
+
+echo "========================================="
+echo "Downloading Ubuntu .deb Packages"
+echo "========================================="
+echo "Output directory: ${OUTPUT_DIR}"
+echo "========================================="
+
+# Run download in Docker container with proper environment
+echo ""
+echo "Running download in Ubuntu 26.04 Docker container..."
+echo ""
+
+docker run --rm \
+    -v "$(pwd)/${OUTPUT_DIR}:/cache/deb" \
+    ubuntu:26.04 \
+    bash -c "
+set -euo pipefail
+
+OUTPUT_DIR='/cache/deb'
+
+# List of all required packages
+PACKAGES=(
+    # Build tools
+    build-essential
+    cmake
+    ninja-build
+    clang
+    gnupg
+    curl
+    jq
+    openssh-client
+    pkg-config
+    unzip
+    
+    # Qt6 libraries
+    libqt6svg6-dev
+    libkf6texttemplate-dev
+    libqt6core6
+    libqt6gui6
+    libqt6widgets6
+    libqt6sql6
+    libqt6sql6-psql
+    libqt6test6
+    qt6-base-dev
+    qt6-l10n-tools
+    qt6-serialport-dev
+    qt6-svg-dev
+    qt6-tools-dev-tools
+    qt6-tools-dev
+    qt6-websockets-dev
+    
+    # Other libraries
+    libgl1-mesa-dev
+    libxkbcommon-x11-0
+    libfontconfig1
+    libdbus-1-3
+    libpulse0
+    libxcb-glx0
+    libxcb-cursor0
+    libbz2-dev
+    libpoppler-dev
+    libpoppler-qt6-dev
+    libboost-dev
+    libgeographiclib-dev
+    libbotan-3-dev
+    libssl-dev
+    libxml2-dev
+    libicu-dev
+    
+    # Testing
+    libgtest-dev
+    libgmock-dev
+    
+    # Database
+    libpq-dev
+    postgresql-server-dev-all
+    
+    # Multimedia
+    libvlc-dev
+    vlc-plugin-base
+    
+    # Python
+    python3
+    python3-venv
+    python3-pip
+    
+    # Packaging
+    rpm
+)
+
+mkdir -p \"\${OUTPUT_DIR}\"
+
+echo 'Updating package lists...'
+apt-get update -qq
+
+echo \"Downloading \${#PACKAGES[@]} packages...\"
+
+# Download all packages with dependencies
+for pkg in \"\${PACKAGES[@]}\"; do
+    echo \"  Downloading \${pkg}...\"
+    apt-get download \"\${pkg}\" || echo \"Warning: Could not download \${pkg}\"
+done
+
+# Move all .deb files to output directory
+echo 'Collecting .deb packages...'
+find / -name \"*.deb\" -type f 2>/dev/null | head -1000 | xargs -I {} cp {} \"\${OUTPUT_DIR}/\" || true
+
+DEB_COUNT=\$(ls -1 \"\${OUTPUT_DIR}\"/*.deb 2>/dev/null | wc -l || echo 0)
+echo ''
+echo '========================================='
+echo 'Download Complete!'
+echo '========================================='
+echo \"Downloaded \${DEB_COUNT} .deb packages to \${OUTPUT_DIR}\"
+echo '========================================='
+
+# Create package list for reference
+cat > /cache/package-list.txt << EOF
+# Ubuntu 26.04 Package List
+# Generated: \$(date -u +\"%Y-%m-%dT%H:%M:%SZ\")
+# Total packages: \${DEB_COUNT}
+
+\$(ls -1 \"\${OUTPUT_DIR}\"/*.deb 2>/dev/null | xargs -n1 basename 2>/dev/null | sort || echo 'No packages downloaded')
+EOF
+
+echo 'Package list created: /cache/package-list.txt'
+"
\ No newline at end of file
diff --git a/external-dependencies/scripts/verify-offline-cache.sh b/external-dependencies/scripts/verify-offline-cache.sh
new file mode 100755
index 000000000..69ebb392a
--- /dev/null
+++ b/external-dependencies/scripts/verify-offline-cache.sh
@@ -0,0 +1,78 @@
+#!/bin/bash
+# Verify Offline Cache Integrity
+# Usage: bash verify-offline-cache.sh [offline-cache-path]
+
+set -euo pipefail
+
+OFFLINE_CACHE="${1:-./offline-cache}"
+
+echo "=== Verifying Offline Cache ==="
+echo "Path: $OFFLINE_CACHE"
+echo ""
+
+ERRORS=0
+
+# Check Qt installation
+echo "Checking Qt 6.10.2..."
+if [ -d "$OFFLINE_CACHE/qt6/6.10.2/gcc_64" ]; then
+    QT_FILES=$(find "$OFFLINE_CACHE/qt6/6.10.2/gcc_64" -type f | wc -l)
+    if [ "$QT_FILES" -ge 12000 ]; then
+        echo "✓ Qt installation complete ($QT_FILES files)"
+    else
+        echo "✗ Qt installation incomplete (expected 12000+, found $QT_FILES)"
+        ERRORS=$((ERRORS + 1))
+    fi
+else
+    echo "✗ Qt installation directory missing"
+    ERRORS=$((ERRORS + 1))
+fi
+
+# Check source tarballs
+echo ""
+echo "Checking source tarballs..."
+for tarball in KDReports-2.3.0.tar.gz Log4Qt-2.0.0.tar.gz grantlee-20d415b.tar.gz; do
+    if [ -f "$OFFLINE_CACHE/src/$tarball" ]; then
+        SIZE=$(du -h "$OFFLINE_CACHE/src/$tarball" | cut -f1)
+        echo "✓ $tarball ($SIZE)"
+    else
+        echo "✗ $tarball missing"
+        ERRORS=$((ERRORS + 1))
+    fi
+done
+
+# Check .deb packages
+echo ""
+echo "Checking Ubuntu .deb packages..."
+if [ -d "$OFFLINE_CACHE/deb" ]; then
+    DEB_COUNT=$(ls -1 "$OFFLINE_CACHE/deb"/*.deb 2>/dev/null | wc -l)
+    if [ "$DEB_COUNT" -ge 49 ]; then
+        echo "✓ Debian packages complete ($DEB_COUNT packages)"
+    else
+        echo "✗ Debian packages incomplete (expected 49+, found $DEB_COUNT)"
+        ERRORS=$((ERRORS + 1))
+    fi
+else
+    echo "✗ Debian packages directory missing"
+    ERRORS=$((ERRORS + 1))
+fi
+
+# Check package list
+echo ""
+echo "Checking package inventory..."
+if [ -f "$OFFLINE_CACHE/scripts/package-list.txt" ]; then
+    echo "✓ Package list present"
+else
+    echo "✗ Package list missing"
+    ERRORS=$((ERRORS + 1))
+fi
+
+# Summary
+echo ""
+echo "=== Verification Summary ==="
+if [ "$ERRORS" -eq 0 ]; then
+    echo "✓ All checks passed"
+    exit 0
+else
+    echo "✗ $ERRORS check(s) failed"
+    exit 1
+fi
\ No newline at end of file