clean code and fix signature to null

app/src/main/java/com/bitchat/android/crypto/EncryptionService.kt

@@ -286,66 +286,3 @@ class EncryptionService(private val context: Context) {
         Log.d(TAG, "🔌 EncryptionService shut down")
     }
 }
-
-/**
- * Message padding utilities - exact same as iOS version
- */
-object MessagePadding {
-    // Standard block sizes for padding
-    private val blockSizes = listOf(256, 512, 1024, 2048)
-    
-    /**
-     * Add PKCS#7-style padding to reach target size
-     */
-    fun pad(data: ByteArray, targetSize: Int): ByteArray {
-        if (data.size >= targetSize) return data
-        
-        val paddingNeeded = targetSize - data.size
-        
-        // PKCS#7 only supports padding up to 255 bytes
-        if (paddingNeeded > 255) return data
-        
-        val padded = ByteArray(targetSize)
-        System.arraycopy(data, 0, padded, 0, data.size)
-        
-        // Fill with random bytes except the last byte
-        val random = SecureRandom()
-        random.nextBytes(padded.sliceArray(data.size until targetSize - 1))
-        
-        // Last byte indicates padding length (PKCS#7)
-        padded[targetSize - 1] = paddingNeeded.toByte()
-        
-        return padded
-    }
-    
-    /**
-     * Remove padding from data
-     */
-    fun unpad(data: ByteArray): ByteArray {
-        if (data.isEmpty()) return data
-        
-        // Last byte tells us how much padding to remove
-        val paddingLength = (data.last().toInt() and 0xFF)
-        if (paddingLength <= 0 || paddingLength > data.size) return data
-        
-        return data.sliceArray(0 until (data.size - paddingLength))
-    }
-    
-    /**
-     * Find optimal block size for data
-     */
-    fun optimalBlockSize(dataSize: Int): Int {
-        // Account for encryption overhead (~16 bytes for AES-GCM tag)
-        val totalSize = dataSize + 16
-        
-        // Find smallest block that fits
-        for (blockSize in blockSizes) {
-            if (totalSize <= blockSize) {
-                return blockSize
-            }
-        }
-        
-        // For very large messages, just use the original size
-        return dataSize
-    }
-}