FAQ 99zk: Pertanyaan Umum & Jawaban Lengkap

99zk_v5.2.1.apk
├── AndroidManifest.xml          # Application manifest (Binary XML format)
│                                # Contains: package name, permissions, components, SDK versions
│                                # Size: 4.2 KB (compressed), 18.7 KB (decompiled XML)
│                                # Deklarasi 14 permissions + 23 activities + 8 services
│
├── classes.dex                  # Primary Dalvik Executable (Java/Kotlin bytecode)
│                                # Size: 18.7 MB - Main application logic
│                                # Methods: 42,156 | Classes: 8,234 | Obfuscated: Yes (ProGuard R8)
│                                # Dieksekusi oleh Android Runtime (ART) dengan JIT/AOT compilation
│
├── classes2.dex                 # Secondary DEX file (Multi-dex support untuk 65K+ methods)
│                                # Size: 8.3 MB - Additional classes & libraries
│                                # Methods: 25,078 | Required untuk aplikasi besar dengan banyak dependency
│
├── resources.arsc               # Compiled resource table (binary format)
│                                # Size: 3.2 MB - Semua strings, dimensions, colors, styles dalam format optimal
│                                # Mendukung multi-language: Bahasa Indonesia (id), English (en), 中文 (zh)
│
├── META-INF/                    # Security & metadata directory - Digital signature files
│   ├── MANIFEST.MF             # Package manifest dengan SHA-256 digest semua files
│   │                           # Berisi: Name + SHA-256-Digest untuk 2,847 entries
│   ├── CERT.SF                 # Signature file - Signed version dari MANIFEST.MF
│   │                           # Algorithm: SHA256withRSA | Signed: 2026-10-15 08:23:14 UTC
│   ├── CERT.RSA                # X.509 v3 certificate (2048-bit RSA public key)
│   │                           # Issuer: CN=99zk Release, OU=Development, O=99zk│   │                           # Valid: 2021-03-15 to 2046-03-09 (25 years validity)
│   │                           # Fingerprint SHA-256: b8c4f7a2d9e1f6a8c3d5b2e9f7a4c8d1...
│   └── dependencies            # Dependency metadata - Library versions & checksums
│
├── res/                        # Resources directory - UI assets & configuration files
│   │
│   ├── drawable/               # Density-independent drawables (vector XML, bitmap PNG/WebP)
│   │   ├── ic_launcher.xml     # Adaptive icon untuk Android 8.0+ (vector drawable)
│   │   ├── ic_logo.webp        # Logo aplikasi (WebP format - 35% lebih kecil dari PNG)
│   │   ├── bg_splash.webp      # Splash screen background (1080x1920px)
│   │   └── [...847 more files] # Button states, icons, illustrations
│   │
│   ├── drawable-mdpi/          # Medium density ~160dpi (older phones)
│   ├── drawable-hdpi/          # High density ~240dpi  
│   ├── drawable-xhdpi/         # Extra-high ~320dpi (most common 2018-2020)
│   ├── drawable-xxhdpi/        # Extra-extra-high ~480dpi (flagship 2020-2023)
│   ├── drawable-xxxhdpi/       # Extra³-high ~640dpi (premium flagship 2024+)
│   │
│   ├── drawable-night/         # Dark mode assets (Android 10+ automatic night mode)
│   │   └── bg_main.xml         # Dark theme backgrounds & colors
│   │
│   ├── layout/                 # UI Layout files (XML) - Activity & Fragment screens
│   │   ├── activity_main.xml   # Main screen layout (ConstraintLayout)
│   │   ├── fragment_home.xml   # Home tab fragment
│   │   ├── item_list.xml       # RecyclerView item layout
│   │   └── [...142 more layouts]
│   │
│   ├── layout-land/            # Landscape orientation layouts (optimized untuk tablet & fold)
│   │   └── activity_main.xml   # Horizontal layout dengan dual-pane design
│   │
│   ├── layout-sw600dp/         # Layouts untuk small tablets (600dp width+)
│   ├── layout-sw720dp/         # Layouts untuk large tablets & Chromebooks
│   │
│   ├── values/                 # Default resource values (bahasa, warna, dimensi, style)
│   │   ├── strings.xml         # 847 string resources (Bahasa Indonesia default)
│   │   ├── colors.xml          # Material Design 3 color palette (48 colors)
│   │   ├── dimens.xml          # Dimensions & spacing (8dp grid system)
│   │   ├── styles.xml          # Theme definitions (Material Components)
│   │   └── attrs.xml           # Custom attributes untuk custom views
│   │
│   ├── values-en/              # English translations (full coverage 847 strings)
│   ├── values-zh/              # Chinese simplified translations
│   ├── values-night/           # Dark mode color overrides
│   │   └── colors.xml          # Dark theme palette
│   │
│   ├── anim/                   # Animation files (XML) - Transitions & motion
│   │   ├── fade_in.xml         # Alpha animation 0.0 → 1.0
│   │   ├── slide_up.xml        # Translation animation dari bottom
│   │   └── scale_bounce.xml    # Scale dengan overshoot interpolator
│   │
│   ├── menu/                   # Menu definitions untuk AppBar, NavigationView, PopupMenu
│   │   ├── menu_main.xml       # Top app bar menu items
│   │   └── menu_nav.xml        # Bottom navigation menu (5 items)
│   │
│   └── raw/                    # Raw asset files (tidak dicompile/optimize)
│       ├── config.json         # Runtime configuration data
│       └── terms.html          # Terms & conditions HTML (offline display)
│
├── assets/                     # Additional assets (uncompressed) - Larger files
│   ├── fonts/                  # Custom typography (TTF/OTF fonts)
│   │   ├── inter_regular.ttf   # Primary font - Inter (UI text)
│   │   ├── inter_bold.ttf      # Bold weight
│   │   └── roboto_mono.ttf     # Monospace font untuk code display
│   ├── database/               # Pre-populated SQLite database
│   │   └── app.db              # Initial data (categories, defaults)
│   └── lottie/                 # Lottie animation JSON files
│       └── loading.json        # Loading animation (after effects export)
│
├── lib/                        # Native libraries (.so files) - Compiled C/C++ code
│   │                           # Built dengan Android NDK r25c | Compiler: Clang 14.0.7
│   │
│   ├── armeabi-v7a/            # ARM 32-bit (devices 2013-2018, budget phones)
│   │   └── libnative.so        # Size: 3.2 MB | Target: ARMv7-A dengan NEON SIMD
│   │
│   ├── arm64-v8a/              # ARM 64-bit (PRIMARY - 95% devices 2020+)
│   │   └── libnative.so        # Size: 4.1 MB | Optimized untuk 64-bit registers
│   │                           # Performance: 20-30% faster, memory: 15% more efficient
│   │
│   ├── x86/                    # Intel 32-bit (Android emulator legacy, rare tablets)
│   │   └── libnative.so        # Size: 3.5 MB | Compatibility layer available
│   │
│   └── x86_64/                 # Intel 64-bit (modern emulator, Chromebooks, Intel tablets)
│       └── libnative.so        # Size: 4.3 MB | Native execution pada Intel processors
│
└── kotlin/                     # Kotlin compiler metadata (for reflection & debugging)
    └── kotlin.kotlin_builtins  # Kotlin standard library signatures
                                 # Required untuk Kotlin reflection & inline functions

$ apksigner verify --verbose --print-certs 99zk_v5.2.1.apk

Verifies
✓ Verified using v1 scheme (JAR signing): true
  └─ Legacy signature (Android 2.3+) | Compatibility: 100% devices
  
✓ Verified using v2 scheme (APK Signature Scheme v2): true
  └─ Full-APK signature (Android 7.0+) | Protection: whole-file integrity
  
✓ Verified using v3 scheme (APK Signature Scheme v3): true
  └─ Enhanced signature (Android 9.0+) | Feature: key rotation support
  
✗ Verified using v4 scheme (APK Signature Scheme v4): false
  └─ Optional V4 untuk streaming install (Google Play only) - Normal untuk side-load APK
  
✗ Verified for SourceStamp: false
  └─ Optional SourceStamp untuk distribution platform ID

Number of signers: 1
  └─ Single developer signature (best practice production apps)

Signer #1 certificate DN:
CN=99zk Release, OU=Development, O=99zk, L=Jakarta, ST=Jakarta, C=ID
  ├─ CN (Common Name): 99zk Release
  ├─ OU (Organizational Unit): Development
  ├─ O (Organization): 99zk  ├─ L (Locality): Jakarta
  ├─ ST (State/Province): Jakarta
  └─ C (Country): ID (Indonesia)

Signer #1 certificate SHA-256 digest:
b8c4f7a2d9e1f6a8c3d5b2e9f7a4c8d1e6f9a2b5c8d3e7f1a4b7c2d6e9f3a8b1
  └─ Primary fingerprint untuk authenticity verification

Signer #1 certificate SHA-1 digest:
a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6q7r8s9t0
  └─ Legacy fingerprint (backward compatibility)

Signer #1 certificate MD5 digest:
1a2b3c4d5e6f7g8h9i0j1k2l3m4n5o6p
  └─ Deprecated (MD5 not secure, only for legacy support)

Signer #1 key algorithm: RSA
  └─ Industry-standard public-key cryptography

Signer #1 key size (bits): 2048
  └─ Security: HIGH | Google Play minimum requirement (2017+)
  └─ Brute force resistance: ~10^617 years dengan hardware 2026

Signer #1 public key SHA-256 digest:
c9d5e8f3a7b2c6d1e9f4a8b3c7d2e6f1a5b9c3d8e2f7a1b6c4d9e3f8a2b7c1d6

Signer #1 public key SHA-1 digest:
b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6q7r8s9t0u1

Signer #1 public key MD5 digest:
2b3c4d5e6f7g8h9i0j1k2l3m4n5o6p7q

WARNING: META-INF/androidx.*.version files: found
  └─ AndroidX library version metadata (SAFE - used by Android Studio)

✓ SUCCESS: APK verified successfully
  ✓ Signature valid & trusted
  ✓ APK tidak dimodifikasi sejak signing
  ✓ Certificate valid hingga 2046-03-09
  ✓ AMAN untuk install & gunakan

# Quick verification
$ apksigner verify 99zk_v5.2.1.apk

# Verbose mode dengan certificate details (recommended)
$ apksigner verify --verbose --print-certs 99zk_v5.2.1.apk

# Output: signature schemes (v1/v2/v3), certificate DN, fingerprints, key info

# Install apksigner:
# - Linux/Mac: apt install apksigner / brew install apksigner
# - Windows: Download Android SDK Build-Tools dari developer.android.com

# Verify dengan verbose output & certificate details
$ jarsigner -verify -verbose -certs 99zk_v5.2.1.apk

# Output: JAR verification status, certificate chain, signer info, validity dates
# Note: Part of JDK, pastikan Java SDK installed (java -version)

# Extract & print certificate info langsung dari APK
$ unzip -p 99zk_v5.2.1.apk META-INF/CERT.RSA | keytool -printcert

# Output lengkap:
#  - Owner DN (Common Name, Org, Location)
#  - Issuer DN (self-signed / CA-signed)
#  - Serial number, validity period
#  - Certificate fingerprints (MD5, SHA-1, SHA-256)
#  - Signature algorithm, public key details

# Alternative: Extract cert file dulu
$ unzip 99zk_v5.2.1.apk META-INF/CERT.RSA
$ keytool -printcert -file META-INF/CERT.RSA