Primer paso de la investigacion. Se aportan el .apk, las carpetas con el apk extraido y el apk descompilado. El archivo API_DOCUMENTATION.md es un archivo donde se anotaran los descubrimientos del funcionamiento de la API, y los .py son scripts para probar la funcionalidad de la API con los métodos que vayamos encontrando. Finalmente, los archivos .js son scripts de Frida para extraer informacion de la APP durante la ejecucion.

apk_decompiled/sources/kotlin/random/KotlinRandom.java

@@ -0,0 +1,83 @@
+package kotlin.random;
+
+import kotlin.Metadata;
+import kotlin.jvm.internal.DefaultConstructorMarker;
+import kotlin.jvm.internal.Intrinsics;
+
+@Metadata(d1 = {"\u0000B\n\u0002\u0018\u0002\n\u0002\u0018\u0002\n\u0000\n\u0002\u0018\u0002\n\u0002\b\u0004\n\u0002\u0010\u000b\n\u0000\n\u0002\u0010\b\n\u0002\b\u0003\n\u0002\u0010\u0002\n\u0000\n\u0002\u0010\u0012\n\u0000\n\u0002\u0010\u0006\n\u0000\n\u0002\u0010\u0007\n\u0002\b\u0003\n\u0002\u0010\t\n\u0002\b\u0004\b\u0002\u0018\u0000 \u001b2\u00020\u0001:\u0001\u001bB\r\u0012\u0006\u0010\u0002\u001a\u00020\u0003¢\u0006\u0002\u0010\u0004J\u0010\u0010\t\u001a\u00020\n2\u0006\u0010\u000b\u001a\u00020\nH\u0014J\b\u0010\f\u001a\u00020\bH\u0016J\u0010\u0010\r\u001a\u00020\u000e2\u0006\u0010\u000f\u001a\u00020\u0010H\u0016J\b\u0010\u0011\u001a\u00020\u0012H\u0016J\b\u0010\u0013\u001a\u00020\u0014H\u0016J\b\u0010\u0015\u001a\u00020\nH\u0016J\u0010\u0010\u0015\u001a\u00020\n2\u0006\u0010\u0016\u001a\u00020\nH\u0016J\b\u0010\u0017\u001a\u00020\u0018H\u0016J\u0010\u0010\u0019\u001a\u00020\u000e2\u0006\u0010\u001a\u001a\u00020\u0018H\u0016R\u0011\u0010\u0002\u001a\u00020\u0003¢\u0006\b\n\u0000\u001a\u0004\b\u0005\u0010\u0006R\u000e\u0010\u0007\u001a\u00020\bX\u0082\u000e¢\u0006\u0002\n\u0000¨\u0006\u001c"}, d2 = {"Lkotlin/random/KotlinRandom;", "Ljava/util/Random;", "impl", "Lkotlin/random/Random;", "(Lkotlin/random/Random;)V", "getImpl", "()Lkotlin/random/Random;", "seedInitialized", "", "next", "", "bits", "nextBoolean", "nextBytes", "", "bytes", "", "nextDouble", "", "nextFloat", "", "nextInt", "bound", "nextLong", "", "setSeed", "seed", "Companion", "kotlin-stdlib"}, k = 1, mv = {1, 9, 0}, xi = 48)
+/* loaded from: classes3.dex */
+final class KotlinRandom extends java.util.Random {
+    private static final Companion Companion = new Companion(null);
+    private static final long serialVersionUID = 0;
+    private final Random impl;
+    private boolean seedInitialized;
+
+    @Metadata(d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0002\b\u0002\n\u0002\u0010\t\n\u0000\b\u0082\u0003\u0018\u00002\u00020\u0001B\u0007\b\u0002¢\u0006\u0002\u0010\u0002R\u000e\u0010\u0003\u001a\u00020\u0004X\u0082T¢\u0006\u0002\n\u0000¨\u0006\u0005"}, d2 = {"Lkotlin/random/KotlinRandom$Companion;", "", "()V", "serialVersionUID", "", "kotlin-stdlib"}, k = 1, mv = {1, 9, 0}, xi = 48)
+    /* loaded from: classes3.dex */
+    public static final class Companion {
+        public /* synthetic */ Companion(DefaultConstructorMarker defaultConstructorMarker) {
+            this();
+        }
+
+        private Companion() {
+        }
+    }
+
+    public KotlinRandom(Random impl) {
+        Intrinsics.checkNotNullParameter(impl, "impl");
+        this.impl = impl;
+    }
+
+    public final Random getImpl() {
+        return this.impl;
+    }
+
+    @Override // java.util.Random
+    public int next(int bits) {
+        return this.impl.nextBits(bits);
+    }
+
+    @Override // java.util.Random
+    public boolean nextBoolean() {
+        return this.impl.nextBoolean();
+    }
+
+    @Override // java.util.Random
+    public void nextBytes(byte[] bytes) {
+        Intrinsics.checkNotNullParameter(bytes, "bytes");
+        this.impl.nextBytes(bytes);
+    }
+
+    @Override // java.util.Random
+    public double nextDouble() {
+        return this.impl.nextDouble();
+    }
+
+    @Override // java.util.Random
+    public float nextFloat() {
+        return this.impl.nextFloat();
+    }
+
+    @Override // java.util.Random
+    public int nextInt() {
+        return this.impl.nextInt();
+    }
+
+    @Override // java.util.Random
+    public long nextLong() {
+        return this.impl.nextLong();
+    }
+
+    @Override // java.util.Random
+    public void setSeed(long seed) {
+        if (this.seedInitialized) {
+            throw new UnsupportedOperationException("Setting seed is not supported.");
+        }
+        this.seedInitialized = true;
+    }
+
+    @Override // java.util.Random
+    public int nextInt(int bound) {
+        return this.impl.nextInt(bound);
+    }
+}