From e2df506b944d8e938a9d47bcd497f705efe4fd85 Mon Sep 17 00:00:00 2001
From: Sam <samdinner@hotmail.com>
Date: Sat, 11 Nov 2023 19:04:47 -0500
Subject: [PATCH] fix(en/aniwave): Fix VRF encrypt/decrypt (#2504)

---
 src/en/aniwave/build.gradle                   |  2 +-
 .../en/nineanime/AniwaveUtils.kt              | 69 +++++++++++++++----
 2 files changed, 55 insertions(+), 16 deletions(-)

diff --git a/src/en/aniwave/build.gradle b/src/en/aniwave/build.gradle
index 8303f9c8ab..b9fe8c46d1 100644
--- a/src/en/aniwave/build.gradle
+++ b/src/en/aniwave/build.gradle
@@ -8,7 +8,7 @@ ext {
     extName = 'Aniwave'
     pkgNameSuffix = 'en.nineanime'
     extClass = '.Aniwave'
-    extVersionCode = 57
+    extVersionCode = 58
     libVersion = '13'
 }
 
diff --git a/src/en/aniwave/src/eu/kanade/tachiyomi/animeextension/en/nineanime/AniwaveUtils.kt b/src/en/aniwave/src/eu/kanade/tachiyomi/animeextension/en/nineanime/AniwaveUtils.kt
index 09f4570a50..05c18e19ca 100644
--- a/src/en/aniwave/src/eu/kanade/tachiyomi/animeextension/en/nineanime/AniwaveUtils.kt
+++ b/src/en/aniwave/src/eu/kanade/tachiyomi/animeextension/en/nineanime/AniwaveUtils.kt
@@ -1,5 +1,6 @@
 package eu.kanade.tachiyomi.animeextension.en.nineanime
 
+import android.util.Base64
 import eu.kanade.tachiyomi.AppInfo
 import eu.kanade.tachiyomi.animeextension.BuildConfig
 import eu.kanade.tachiyomi.network.GET
@@ -10,6 +11,9 @@ import okhttp3.Headers
 import okhttp3.OkHttpClient
 import okhttp3.Response
 import uy.kohesive.injekt.injectLazy
+import java.net.URLDecoder
+import javax.crypto.Cipher
+import javax.crypto.spec.SecretKeySpec
 
 class AniwaveUtils(private val client: OkHttpClient, private val headers: Headers) {
 
@@ -37,22 +41,10 @@ class AniwaveUtils(private val client: OkHttpClient, private val headers: Header
                     headers = userAgent,
                 ),
             ).execute().parseAs<RawResponse>().rawURL
+        } else if (action == "decrypt") {
+            vrfDecrypt(query)
         } else {
-            client.newCall(
-                GET("https://9anime.eltik.net/$action?query=$query&apikey=aniyomi", userAgent),
-            ).execute().use {
-                val body = it.body.string()
-                when (action) {
-                    "decrypt" -> {
-                        json.decodeFromString<VrfResponse>(body).url
-                    }
-                    else -> {
-                        json.decodeFromString<VrfResponse>(body).let { vrf ->
-                            "${vrf.vrfQuery}=${java.net.URLEncoder.encode(vrf.url, "utf-8")}"
-                        }
-                    }
-                }
-            }
+            "vrf=${java.net.URLEncoder.encode(vrfEncrypt(query), "utf-8")}"
         }
     }
 
@@ -60,4 +52,51 @@ class AniwaveUtils(private val client: OkHttpClient, private val headers: Header
         val responseBody = use { it.body.string() }
         return json.decodeFromString(responseBody)
     }
+
+    private fun vrfEncrypt(input: String): String {
+        val rc4Key = SecretKeySpec("ysJhV6U27FVIjjuk".toByteArray(), "RC4")
+        val cipher = Cipher.getInstance("RC4")
+        cipher.init(Cipher.DECRYPT_MODE, rc4Key, cipher.parameters)
+
+        var vrf = cipher.doFinal(input.toByteArray())
+        vrf = Base64.encode(vrf, Base64.URL_SAFE or Base64.NO_WRAP)
+        vrf = Base64.encode(vrf, Base64.DEFAULT or Base64.NO_WRAP)
+        vrf = vrfShift(vrf)
+        vrf = Base64.encode(vrf, Base64.DEFAULT)
+        vrf = rot13(vrf)
+
+        return vrf.toString(Charsets.UTF_8)
+    }
+
+    private fun vrfDecrypt(input: String): String {
+        var vrf = input.toByteArray()
+        vrf = Base64.decode(vrf, Base64.URL_SAFE)
+
+        val rc4Key = SecretKeySpec("hlPeNwkncH0fq9so".toByteArray(), "RC4")
+        val cipher = Cipher.getInstance("RC4")
+        cipher.init(Cipher.DECRYPT_MODE, rc4Key, cipher.parameters)
+        vrf = cipher.doFinal(vrf)
+
+        return URLDecoder.decode(vrf.toString(Charsets.UTF_8), "utf-8")
+    }
+
+    private fun rot13(vrf: ByteArray): ByteArray {
+        for (i in vrf.indices) {
+            val byte = vrf[i]
+            if (byte in 'A'.code..'Z'.code) {
+                vrf[i] = ((byte - 'A'.code + 13) % 26 + 'A'.code).toByte()
+            } else if (byte in 'a'.code..'z'.code) {
+                vrf[i] = ((byte - 'a'.code + 13) % 26 + 'a'.code).toByte()
+            }
+        }
+        return vrf
+    }
+
+    private fun vrfShift(vrf: ByteArray): ByteArray {
+        for (i in vrf.indices) {
+            val shift = arrayOf(-3, 3, -4, 2, -2, 5, 4, 5)[i % 8]
+            vrf[i] = vrf[i].plus(shift).toByte()
+        }
+        return vrf
+    }
 }