fix(PR): story decryption by hazelnut27

Enhance media encryption handling with hybrid resolver and improved decryption methods

common/src/main/kotlin/me/eternal/purrfectsnap/common/data/download/MediaEncryptionKeyPair.kt

@@ -9,7 +9,6 @@ import javax.crypto.spec.SecretKeySpec
 import kotlin.io.encoding.Base64
 import kotlin.io.encoding.ExperimentalEncodingApi
 
-// key and iv are base64 encoded into url safe strings
 data class MediaEncryptionKeyPair(
     val key: String,
     val iv: String,

core/src/main/kotlin/me/eternal/purrfectsnap/core/features/impl/downloader/MediaDownloader.kt

@@ -48,11 +48,18 @@ import me.eternal.purrfectsnap.core.wrapper.impl.media.opera.ParamMap
 import me.eternal.purrfectsnap.core.wrapper.impl.media.toKeyPair
 import me.eternal.purrfectsnap.core.wrapper.impl.media.EncryptionWrapper
 import me.eternal.purrfectsnap.mapper.impl.OperaPageViewControllerMapper
+import me.eternal.purrfectsnap.core.wrapper.impl.media.SnapCipherMode
+import me.eternal.purrfectsnap.core.wrapper.impl.media.toKeyPairUrlSafe
+import me.eternal.purrfectsnap.core.wrapper.impl.media.HybridEncryptionResolver
+import me.eternal.purrfectsnap.core.wrapper.AbstractWrapper
 import java.nio.file.Paths
 import java.util.UUID
 import kotlin.coroutines.suspendCoroutine
 import kotlin.math.absoluteValue
 import android.util.Base64
+import javax.crypto.Cipher
+import javax.crypto.spec.IvParameterSpec
+import javax.crypto.spec.SecretKeySpec
 
 class SnapChapterInfo(
     val offset: Long,
@@ -205,37 +212,6 @@ class MediaDownloader : MessagingRuleFeature("MediaDownloader", MessagingRuleTyp
         }
     }
 
-    private fun extractStoryEncryption(paramMap: ParamMap): MediaEncryptionKeyPair? {
-
-        val keyRaw = paramMap["CONTEXT_REPLY_MEDIA_KEY"] as? String
-            ?: paramMap["REPLY_MEDIA_KEY"] as? String
-            ?: return null
-
-        val ivRaw = paramMap["CONTEXT_REPLY_MEDIA_IV"] as? String
-            ?: paramMap["REPLY_MEDIA_IV"] as? String
-            ?: return null
-
-        return try {
-
-            val keyBytes = android.util.Base64.decode(keyRaw, android.util.Base64.DEFAULT)
-            val ivBytes  = android.util.Base64.decode(ivRaw,  android.util.Base64.DEFAULT)
-
-            if (keyBytes.size != 32 || ivBytes.size != 16) {
-                return null
-            }
-
-            MediaEncryptionKeyPair(
-                key = android.util.Base64.encodeToString(keyBytes, android.util.Base64.NO_WRAP),
-                iv  = android.util.Base64.encodeToString(ivBytes,  android.util.Base64.NO_WRAP),
-                urlSafe = false
-            )
-
-        } catch (e: Exception) {
-            context.log.error("Story AES decode failed", e)
-            null
-        }
-    }
-
     private fun downloadOperaMedia(
         downloadManagerClient: DownloadManagerClient,
         mediaInfoMap: Map<SplitMediaAssetType, MediaInfo>,
@@ -243,69 +219,50 @@ class MediaDownloader : MessagingRuleFeature("MediaDownloader", MessagingRuleTyp
     ) {
         if (mediaInfoMap.isEmpty()) return
 
-        val storyKeyPair = extractStoryEncryption(paramMap)
-
-        val originalMediaInfo = mediaInfoMap[SplitMediaAssetType.ORIGINAL]!!
-        val originalMediaInfoReference = handleLocalReferences(originalMediaInfo.uri)
-
+        // Story Snap Entry (images)
         paramMap["SNAP_ID"]?.toString()?.let { snapId ->
             context.database.getStorySnapEntry(snapId)?.let { storySnapEntry ->
 
-                val urlToDownload = storySnapEntry?.mediaUrl ?: originalMediaInfo.uri
-                val encryptionPair =
-                    safeGetEncryptionPair(originalMediaInfo)
-                        ?: extractStoryEncryption(paramMap)
-
                 downloadManagerClient.downloadSingleMedia(
-                    originalMediaInfoReference,
-                    DownloadMediaType.fromUri(Uri.parse(originalMediaInfoReference)),
-                    encryptionPair
+                    storySnapEntry.mediaUrl ?: throw Exception("Media URL not found"),
+                    DownloadMediaType.fromUri(Uri.parse(storySnapEntry.mediaUrl)),
+                    (storySnapEntry.mediaKey to storySnapEntry.mediaIv)
+                        .takeIf { it.first != null && it.second != null }
+                        ?.let { (key, iv) -> MediaEncryptionKeyPair(key!!, iv!!, urlSafe = false) }
                 )
-
                 return
             }
         }
 
+        val originalMediaInfo = mediaInfoMap[SplitMediaAssetType.ORIGINAL]!!
+        val originalMediaInfoReference = handleLocalReferences(originalMediaInfo.uri)
+
+        // Overlay (if present)
         mediaInfoMap[SplitMediaAssetType.OVERLAY]?.let { overlay ->
             val overlayReference = handleLocalReferences(overlay.uri)
 
-            val originalEncryption = safeGetEncryptionPair(originalMediaInfo)
-            val overlayEncryption = overlay.encryption?.toKeyPair()
-
             downloadManagerClient.downloadMediaWithOverlay(
                 original = InputMedia(
                     originalMediaInfoReference,
                     DownloadMediaType.fromUri(Uri.parse(originalMediaInfoReference)),
-                    encryption = originalEncryption
+                    originalMediaInfo.encryption?.toKeyPair()
                 ),
                 overlay = InputMedia(
                     overlayReference,
                     DownloadMediaType.fromUri(Uri.parse(overlayReference)),
-                    encryption = overlayEncryption,
+                    overlay.encryption?.toKeyPair(),
                     isOverlay = true
                 )
             )
             return
         }
 
-        // fallback to single media download
-        val encryptionPair =
-            storyKeyPair ?: safeGetEncryptionPair(originalMediaInfo)
-
+        // Single media (video/DASH)
         downloadManagerClient.downloadSingleMedia(
             originalMediaInfoReference,
             DownloadMediaType.fromUri(Uri.parse(originalMediaInfoReference)),
-            encryptionPair
+            originalMediaInfo.encryption?.toKeyPair()
         )
-
-    }
-
-    private fun safeGetEncryptionPair(info: MediaInfo?): MediaEncryptionKeyPair? {
-        val enc = info?.encryption ?: return null
-        return runCatching {
-            enc.toKeyPair()
-        }.onFailure { context.log.verbose("Failed to parse encryption key pair → ${info.uri}")
-        }.getOrNull()
     }
 
     fun canAutoDownloadMessage(databaseMessage: ConversationMessage): Boolean {
@@ -313,32 +270,6 @@ class MediaDownloader : MessagingRuleFeature("MediaDownloader", MessagingRuleTyp
         return canUseRule(databaseMessage.clientConversationId!!)
     }
 
-    private fun resolveMediaUrl(raw: String): String {
-            var url = raw.trim()
-
-            // Remove garbage prefix/suffix sometimes present
-            if (url.contains("https://")) {
-                url = url.substringAfter("https://")
-                url = "https://$url"
-            }
-
-            val knownGoodPrefixes = listOf(
-                "https://cf-st.sc-cdn.net",
-                "https://bolt-gcdn.sc-cdn.net",
-                "https://app.snapchat.com",
-                "https://cf-st-nl1.sc-cdn.net"  // sometimes region specific
-            )
-
-            return when {
-                url.startsWith("http") -> url
-                knownGoodPrefixes.any { url.contains(it) } -> url.substringAfterLast("http")
-                else -> "${RemoteMediaResolver.CF_ST_CDN_D}/$url"
-            }.also { resolved ->
-                if (resolved != raw) {
-                    context.log.debug("URL rewritten: $raw → $resolved")
-                }
-            }
-        }
     /**
      * Handles the media from the opera viewer
      *
@@ -347,105 +278,94 @@ class MediaDownloader : MessagingRuleFeature("MediaDownloader", MessagingRuleTyp
      * @param forceDownload if the media should be downloaded
      */
     private fun handleOperaMedia(
-        paramMap: ParamMap, 
-        mediaInfoMap: Map<SplitMediaAssetType, 
-        MediaInfo>, 
-        forceDownload: Boolean, 
+        paramMap: ParamMap,
+        mediaInfoMap: Map<SplitMediaAssetType, MediaInfo>,
+        forceDownload: Boolean,
         forceAllowDuplicate: Boolean = false
     ) {
-
-        //messages
+        
+        // ─── Messages ─────────────────────────
         paramMap["MESSAGE_ID"]?.toString()?.takeIf { forceDownload || shouldAutoDownload("friend_snaps") }?.let { id ->
-            val messageId = id.substring(id.lastIndexOf(":") + 1).toLong()
-            val conversationMessage = context.database.getConversationMessageFromId(messageId)!!
-
+            val messageId = id.substringAfterLast(":").toLong()
+            val conversationMessage = context.database.getConversationMessageFromId(messageId) ?: return@let
             val conversationId = conversationMessage.clientConversationId!!
 
-            if (!forceDownload && !canUseRule(conversationId)) {
-                return
-            }
+            if (!forceDownload && !canUseRule(conversationId)) return@let
 
             val senderId = conversationMessage.senderId!!
+            if (!forceDownload && context.config.downloader.preventSelfAutoDownload.get() &&
+                senderId == context.database.myUserId
+            ) return@let
 
-            if (!forceDownload && context.config.downloader.preventSelfAutoDownload.get() && senderId == context.database.myUserId) return
-
-            val author = context.database.getFriendInfo(senderId) ?: return
+            val author = context.database.getFriendInfo(senderId) ?: return@let
             val authorUsername = author.usernameForSorting!!
-            val mediaId = paramMap["MEDIA_ID"]?.toString()?.let {
-                if (it.contains("-")) it.substringAfter("-")
-                else it
-            }?.substringBefore(".")
-
-            downloadOperaMedia(provideDownloadManagerClient(
-                mediaIdentifier = "$conversationId$senderId${conversationMessage.serverMessageId}$mediaId",
-                mediaAuthor = authorUsername,
-                creationTimestamp = conversationMessage.creationTimestamp,
-                downloadSource = MediaDownloadSource.CHAT_MEDIA,
-                friendInfo = author,
-                forceAllowDuplicate = forceAllowDuplicate
-            ), mediaInfoMap, paramMap)
+            val mediaId = paramMap["MEDIA_ID"]?.toString()?.substringAfter("-")?.substringBefore(".") ?: ""
 
+            downloadOperaMedia(
+                provideDownloadManagerClient(
+                    mediaIdentifier = "$conversationId$senderId${conversationMessage.serverMessageId}$mediaId",
+                    mediaAuthor = authorUsername,
+                    creationTimestamp = conversationMessage.creationTimestamp,
+                    downloadSource = MediaDownloadSource.CHAT_MEDIA,
+                    friendInfo = author,
+                    forceAllowDuplicate = forceAllowDuplicate
+                ),
+                mediaInfoMap,
+                paramMap
+            )
             return
         }
 
-        //private stories
+        // ─── Private Friend Story ─────────────────────────
         paramMap["PLAYLIST_V2_GROUP"]?.takeIf {
             forceDownload || shouldAutoDownload("friend_stories")
         }?.let { playlistGroup ->
             val playlistGroupString = playlistGroup.toString()
 
-            // Try multiple possible keys/paths in order of likelihood
-            val storyUserId = sequenceOf(
-                // Most common new locations
-                { paramMap["STORY_USER_ID"]?.toString() },
-                { paramMap["CREATOR_USER_ID"]?.toString() },
-                { paramMap["USER_ID"]?.toString() },
-                { paramMap["TOPIC_SNAP_CREATOR_USER_ID"]?.toString() },
-                // Old ones as fallback
-                { paramMap["PLAYABLE_STORY_SNAP_RECORD"]
-                    ?.toString()
-                    ?.substringAfter("userId=")
-                    ?.substringBefore(",") },
-                // Parse playlistGroup string more carefully
-                { playlistGroupString.substringAfter("userId=", missingDelimiterValue = "").substringBefore(",") },
-                { playlistGroupString.substringAfter("storyUserId=", missingDelimiterValue = "").substringBefore(",") },
-                // Last desperate fallback — sometimes it's in nested snap record
-                { paramMap["SNAP_PLAYLIST_ITEM"]
-                    ?.toString()
-                    ?.substringAfter("userId=")
-                    ?.substringBefore(",") }
-            ).mapNotNull { it() }.firstOrNull { it.isNotBlank() && it != "null" }
+            val storyUserId = paramMap["TOPIC_SNAP_CREATOR_USER_ID"]?.toString() ?: paramMap["PLAYABLE_STORY_SNAP_RECORD"]?.toString()?.let {
+                if (it.contains("userId=")) it.substringAfter("userId=").substringBefore(",") else null
+            } ?: if (playlistGroupString.contains("storyUserId=")) {
+                playlistGroupString.substringAfter("storyUserId=").substringBefore(",")
+            } else {
+                //story replies
+                val arroyoMessageId = playlistGroup::class.java.methods.firstOrNull { it.name == "getId" }
+                    ?.invoke(playlistGroup)?.toString()
+                    ?.split(":")?.getOrNull(2) ?: return@let
 
-            // ──────────────────────────────────────────────
-
-            val authorUserId = storyUserId ?: run {
-                context.log.warn("[FriendStories] Could not extract user ID — falling back to current user")
-                context.database.myUserId   // prevents crash, but will tag as self
+                val conversationMessage = context.database.getConversationMessageFromId(arroyoMessageId.toLong()) ?: return@let
+                val conversationParticipants = context.database.getConversationParticipants(conversationMessage.clientConversationId.toString()) ?: return@let
+                conversationParticipants.firstOrNull { it != conversationMessage.senderId }
             }
 
-            val author = context.database.getFriendInfo(authorUserId)
-                ?: context.database.getFriendInfoByUsername(authorUserId)   // sometimes it's username
-                ?: throw Exception("No friend info for ID: $authorUserId")
-
-            val authorName = author.usernameForSorting ?: author.displayName ?: "UnknownFriend"
+            val author = context.database.getFriendInfo(
+                if (storyUserId == null || storyUserId == "null")
+                    context.database.myUserId
+                else storyUserId
+            ) ?: throw Exception("Friend not found in database")
+            val authorName = author.usernameForSorting!!
 
             if (!forceDownload) {
                 if (context.config.downloader.preventSelfAutoDownload.get() && author.userId == context.database.myUserId) return
                 if (!canUseRule(author.userId!!)) return
             }
 
-            downloadOperaMedia(provideDownloadManagerClient(
-                mediaIdentifier = paramMap["MEDIA_ID"].toString(),
-                mediaAuthor = authorName,
-                creationTimestamp = paramMap["PLAYABLE_STORY_SNAP_RECORD"]?.toString()?.substringAfter("timestamp=")
-                    ?.substringBefore(",")?.toLongOrNull(),
-                downloadSource = MediaDownloadSource.STORY,
-                friendInfo = author,
-                forceAllowDuplicate = forceAllowDuplicate,
-            ), mediaInfoMap, paramMap)
+            downloadOperaMedia(
+                provideDownloadManagerClient(
+                    mediaIdentifier = paramMap["MEDIA_ID"].toString(),
+                    mediaAuthor = authorName,
+                    creationTimestamp = paramMap["PLAYABLE_STORY_SNAP_RECORD"]?.toString()?.substringAfter("timestamp=")
+                        ?.substringBefore(",")?.toLongOrNull(),
+                    downloadSource = MediaDownloadSource.STORY,
+                    friendInfo = author,
+                    forceAllowDuplicate = forceAllowDuplicate
+                ),
+                mediaInfoMap,
+                paramMap
+            )
             return
         }
 
+        // ─── Public Stories / Spotlight ───────────────────
         val snapSource = paramMap["SNAP_SOURCE"].toString()
 
         //spotlight
@@ -480,7 +400,13 @@ class MediaDownloader : MessagingRuleFeature("MediaDownloader", MessagingRuleTyp
                 return "${(hours % 24).toString().padStart(2, '0')}:${(minutes % 60).toString().padStart(2, '0')}:${(seconds % 60).toString().padStart(2, '0')}"
             }
 
-            val playlistUrl = resolveMediaUrl(paramMap["MEDIA_ID"].toString())
+            val playlistUrl = paramMap["MEDIA_ID"].toString().let {
+                val urlIndexes = arrayOf(it.indexOf("https://cf-st.sc-cdn.net"), it.indexOf("https://bolt-gcdn.sc-cdn.net"))
+
+                urlIndexes.firstOrNull { index -> index != -1 }?.let { validIndex ->
+                    it.substring(validIndex)
+                } ?: "${RemoteMediaResolver.CF_ST_CDN_D}$it"
+            }
 
             context.runOnUiThread {
                 val selectedChapters = mutableListOf<Int>()
@@ -810,7 +736,7 @@ class MediaDownloader : MessagingRuleFeature("MediaDownloader", MessagingRuleTyp
         if (!isPreview) {
             if (forceDownloadFirst ||
                 decodedAttachments.size == 1 ||
-                context.isMainActivityPaused // we can't show alert dialogs when it downloads from a notification, so it downloads the first one
+                context.isMainActivityPaused
             ) {
                 downloadMessageAttachments(friendInfo, message, authorName,
                     listOf(decodedAttachments.first()),

core/src/main/kotlin/me/eternal/purrfectsnap/core/wrapper/impl/media/EncryptionWrapper.kt

@@ -1,5 +1,7 @@
 package me.eternal.purrfectsnap.core.wrapper.impl.media
 
+import android.util.Base64
+import android.util.Log
 import me.eternal.purrfectsnap.common.data.download.MediaEncryptionKeyPair
 import me.eternal.purrfectsnap.core.wrapper.AbstractWrapper
 import java.io.InputStream
@@ -10,83 +12,206 @@ import javax.crypto.CipherInputStream
 import javax.crypto.CipherOutputStream
 import javax.crypto.spec.IvParameterSpec
 import javax.crypto.spec.SecretKeySpec
-import kotlin.io.encoding.ExperimentalEncodingApi
-import android.util.Base64
+
+// Cipher mode enum
 
 enum class SnapCipherMode {
     CBC,
     CTR
 }
 
+// Encryption Wrapper
+
 class EncryptionWrapper(
-    instance: Any?,
+    instance: Any? = null,
     private val mode: SnapCipherMode = SnapCipherMode.CBC
 ) : AbstractWrapper(instance) {
 
-    fun decrypt(data: ByteArray?): ByteArray {
-        return newCipher(Cipher.DECRYPT_MODE).doFinal(data)
+    // Manual key injection (story fallback)
+
+    private var manualKey: ByteArray? = null
+    private var manualIv: ByteArray? = null
+
+    constructor(
+        key: ByteArray,
+        iv: ByteArray,
+        mode: SnapCipherMode = SnapCipherMode.CBC
+    ) : this(null, mode) {
+        manualKey = key
+        manualIv = iv
     }
 
-    fun decrypt(inputStream: InputStream?): InputStream {
-        return CipherInputStream(inputStream, newCipher(Cipher.DECRYPT_MODE))
-    }
-
-    fun decrypt(outputStream: OutputStream?): OutputStream {
-        return CipherOutputStream(outputStream, newCipher(Cipher.DECRYPT_MODE))
-    }
-
-    fun newCipher(modeInt: Int): Cipher {
-        val cipher = cipher
-        cipher.init(
-            modeInt,
-            SecretKeySpec(keySpec, "AES"),
-            IvParameterSpec(ivKeyParameterSpec)
-        )
-        return cipher
-    }
-
-    /**
-     * Dynamic cipher selection
-     */
-    private val cipher: Cipher
-        get() = when (mode) {
-            SnapCipherMode.CBC ->
-                Cipher.getInstance("AES/CBC/PKCS5Padding")
-
-            SnapCipherMode.CTR ->
-                Cipher.getInstance("AES/CTR/NoPadding")
-        }
+    // Key + IV extraction
 
     val keySpec: ByteArray by lazy {
-        searchByteArrayField(32)[instance] as ByteArray
+        manualKey ?: searchByteArrayField(32)[instance] as ByteArray
     }
 
     val ivKeyParameterSpec: ByteArray by lazy {
-        searchByteArrayField(16)[instance] as ByteArray
+        manualIv ?: searchByteArrayField(16)[instance] as ByteArray
     }
 
-    private fun searchByteArrayField(arrayLength: Int): Field {
-        return instanceNonNull()::class.java.fields.first { f ->
+    private fun searchByteArrayField(length: Int): Field {
+        return instanceNonNull()::class.java.declaredFields.first { field ->
             try {
-                if (!f.type.isArray ||
-                    f.type.componentType != Byte::class.javaPrimitiveType
+                field.isAccessible = true
+
+                if (!field.type.isArray ||
+                    field.type.componentType != Byte::class.javaPrimitiveType
                 ) return@first false
 
-                (f.get(instanceNonNull()) as ByteArray).size == arrayLength
+                val value = field.get(instanceNonNull()) as? ByteArray
+                value?.size == length
+
             } catch (_: Exception) {
                 false
             }
         }
     }
+
+    // Cipher builders
+
+    /** Chat media */
+    private fun buildCBCCipherPKCS5(mode: Int): Cipher {
+        return Cipher.getInstance("AES/CBC/PKCS5Padding").apply {
+            init(
+                mode,
+                SecretKeySpec(keySpec, "AES"),
+                IvParameterSpec(ivKeyParameterSpec)
+            )
+        }
+    }
+
+    /** Story images */
+    private fun buildCBCCipherNoPadding(mode: Int): Cipher {
+        return Cipher.getInstance("AES/CBC/NoPadding").apply {
+            init(
+                mode,
+                SecretKeySpec(keySpec, "AES"),
+                IvParameterSpec(ivKeyParameterSpec)
+            )
+        }
+    }
+
+    /** Videos + DASH */
+    private fun buildCTRCipher(mode: Int): Cipher {
+        return Cipher.getInstance("AES/CTR/NoPadding").apply {
+            init(
+                mode,
+                SecretKeySpec(keySpec, "AES"),
+                IvParameterSpec(ivKeyParameterSpec)
+            )
+        }
+    }
+
+    // Generic decrypt (auto detect)
+
+    fun decrypt(data: ByteArray): ByteArray {
+
+        Log.d(
+            "PurrfectSnap",
+            "Decrypt → keySize=${keySpec.size} ivSize=${ivKeyParameterSpec.size}"
+        )
+
+        return try {
+            buildCBCCipherPKCS5(Cipher.DECRYPT_MODE).doFinal(data)
+
+        } catch (cbcError: Exception) {
+
+            Log.d("PurrfectSnap", "PKCS5 failed → trying CTR")
+
+            buildCTRCipher(Cipher.DECRYPT_MODE).doFinal(data)
+        }
+    }
+
+    // Image decrypt (story + chat safe)
+
+    fun decryptImage(data: ByteArray): ByteArray {
+
+        Log.d(
+            "PurrfectSnap",
+            "Image Decrypt → keySize=${keySpec.size} ivSize=${ivKeyParameterSpec.size}"
+        )
+
+        return try {
+            // Story images
+            buildCBCCipherNoPadding(Cipher.DECRYPT_MODE).doFinal(data)
+
+        } catch (noPadError: Exception) {
+
+            Log.d("PurrfectSnap", "CBC NoPadding failed → trying PKCS5")
+
+            try {
+                // Chat images
+                buildCBCCipherPKCS5(Cipher.DECRYPT_MODE).doFinal(data)
+
+            } catch (pkcsError: Exception) {
+
+                Log.d("PurrfectSnap", "PKCS5 failed → trying CTR")
+
+                // Edge fallback
+                buildCTRCipher(Cipher.DECRYPT_MODE).doFinal(data)
+            }
+        }
+    }
+
+    // Stream decrypt
+
+    fun decrypt(input: InputStream): InputStream {
+        val cipher = try {
+            buildCBCCipherPKCS5(Cipher.DECRYPT_MODE)
+        } catch (_: Exception) {
+            buildCTRCipher(Cipher.DECRYPT_MODE)
+        }
+
+        return CipherInputStream(input, cipher)
+    }
+
+    fun decryptImage(input: InputStream): InputStream {
+
+        val cipher = try {
+            buildCBCCipherNoPadding(Cipher.DECRYPT_MODE)
+        } catch (_: Exception) {
+            buildCBCCipherPKCS5(Cipher.DECRYPT_MODE)
+        }
+
+        return CipherInputStream(input, cipher)
+    }
+
+    fun decrypt(output: OutputStream): OutputStream {
+
+        val cipher = try {
+            buildCBCCipherPKCS5(Cipher.DECRYPT_MODE)
+        } catch (_: Exception) {
+            buildCTRCipher(Cipher.DECRYPT_MODE)
+        }
+
+        return CipherOutputStream(output, cipher)
+    }
 }
 
-@OptIn(ExperimentalEncodingApi::class)
+// KeyPair Extensions
+
+/** Standard Base64 */
 fun EncryptionWrapper.toKeyPair(): MediaEncryptionKeyPair {
     return MediaEncryptionKeyPair(
-        key = android.util.Base64.encodeToString(this.keySpec, android.util.Base64.NO_WRAP),
-        iv  = android.util.Base64.encodeToString(this.ivKeyParameterSpec, android.util.Base64.NO_WRAP),
-        urlSafe = true
+        key = Base64.encodeToString(this.keySpec, Base64.NO_WRAP),
+        iv = Base64.encodeToString(this.ivKeyParameterSpec, Base64.NO_WRAP),
+        urlSafe = false
     )
 }
 
-
+/** URL Safe (story media) */
+fun EncryptionWrapper.toKeyPairUrlSafe(): MediaEncryptionKeyPair {
+    return MediaEncryptionKeyPair(
+        key = Base64.encodeToString(
+            this.keySpec,
+            Base64.URL_SAFE or Base64.NO_WRAP
+        ),
+        iv = Base64.encodeToString(
+            this.ivKeyParameterSpec,
+            Base64.URL_SAFE or Base64.NO_WRAP
+        ),
+        urlSafe = true
+    )
+}

core/src/main/kotlin/me/eternal/purrfectsnap/core/wrapper/impl/media/HybridEncryptionResolver.kt

@@ -0,0 +1,56 @@
+package me.eternal.purrfectsnap.core.wrapper.impl.media
+
+import android.util.Base64
+import me.eternal.purrfectsnap.common.data.download.MediaEncryptionKeyPair
+import javax.crypto.Cipher
+import javax.crypto.spec.IvParameterSpec
+import javax.crypto.spec.SecretKeySpec
+
+object HybridEncryptionResolver {
+
+    fun resolve(
+        mediaInfo: MediaInfo,
+        storyKeyPair: MediaEncryptionKeyPair?
+    ): MediaEncryptionKeyPair? {
+
+        // ────OLD WRAPPER (images/snaps)───────────────────
+        val wrapperPair = runCatching {
+            mediaInfo.encryption?.toKeyPair()
+        }.getOrNull()
+
+        if (wrapperPair != null) {
+            return wrapperPair
+        }
+
+        // ────DIRECT MEDIAINFO KEYPAIR────────────────
+        val directPair = runCatching {
+            mediaInfo.encryption?.toKeyPairUrlSafe()
+        }.getOrNull()
+
+        if (directPair != null) {
+            return directPair
+        }
+
+        // ────STORY PARAMMAP AES─────────────────
+        if (storyKeyPair != null) {
+            return storyKeyPair
+        }
+
+        // ────NONE FOUND─────────────────
+        return null
+    }
+
+    // Optional cipher builder if needed elsewhere
+    fun buildCipher(pair: MediaEncryptionKeyPair): Cipher {
+        val key = Base64.decode(pair.key, Base64.DEFAULT)
+        val iv  = Base64.decode(pair.iv, Base64.DEFAULT)
+
+        return Cipher.getInstance("AES/CBC/PKCS5Padding").apply {
+            init(
+                Cipher.DECRYPT_MODE,
+                SecretKeySpec(key, "AES"),
+                IvParameterSpec(iv)
+            )
+        }
+    }
+}