feat: Implement JSON serialization for message attachments with decryption support

2026-01-13 05:04:05 +05:00
parent af10005879
commit f6409a9474
3 changed files with 223 additions and 4 deletions
--- a/app/src/main/java/com/rosetta/messenger/crypto/MessageCrypto.kt
+++ b/app/src/main/java/com/rosetta/messenger/crypto/MessageCrypto.kt
@@ -637,6 +637,88 @@ object MessageCrypto {
        
        return plaintext
    }
+    
+    /**
+     * Расшифровка MESSAGES attachment blob
+     * Формат: ivBase64:ciphertextBase64
+     * Использует PBKDF2 + AES-256-CBC + zlib decompression
+     */
+    fun decryptAttachmentBlob(
+        encryptedData: String,
+        encryptedKey: String,
+        myPrivateKey: String
+    ): String? {
+        return try {
+            // 1. Расшифровываем ChaCha ключ (как для сообщений)
+            val keyAndNonce = decryptKeyFromSender(encryptedKey, myPrivateKey)
+            
+            // 2. Конвертируем key+nonce в строку (как в RN: key.toString('utf-8'))
+            val chachaKeyString = String(keyAndNonce, Charsets.UTF_8)
+            
+            // 3. Генерируем PBKDF2 ключ (salt='rosetta', 1000 iterations, sha256)
+            val pbkdf2Key = generatePBKDF2Key(chachaKeyString)
+            
+            // 4. Расшифровываем AES-256-CBC
+            decryptWithPBKDF2Key(encryptedData, pbkdf2Key)
+        } catch (e: Exception) {
+            android.util.Log.e("MessageCrypto", "❌ Failed to decrypt attachment blob", e)
+            null
+        }
+    }
+    
+    /**
+     * Генерация PBKDF2 ключа (совместимо с RN)
+     */
+    private fun generatePBKDF2Key(password: String, salt: String = "rosetta", iterations: Int = 1000): ByteArray {
+        val factory = javax.crypto.SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256")
+        val spec = javax.crypto.spec.PBEKeySpec(
+            password.toCharArray(),
+            salt.toByteArray(Charsets.UTF_8),
+            iterations,
+            256 // 32 bytes
+        )
+        return factory.generateSecret(spec).encoded
+    }
+    
+    /**
+     * Расшифровка с PBKDF2 ключом (AES-256-CBC + zlib)
+     * Формат: ivBase64:ciphertextBase64
+     */
+    private fun decryptWithPBKDF2Key(encryptedData: String, pbkdf2Key: ByteArray): String? {
+        return try {
+            val parts = encryptedData.split(":")
+            if (parts.size != 2) {
+                android.util.Log.e("MessageCrypto", "Invalid encrypted data format")
+                return null
+            }
+            
+            val iv = android.util.Base64.decode(parts[0], android.util.Base64.DEFAULT)
+            val ciphertext = android.util.Base64.decode(parts[1], android.util.Base64.DEFAULT)
+            
+            // AES-256-CBC расшифровка
+            val cipher = javax.crypto.Cipher.getInstance("AES/CBC/PKCS5Padding")
+            val secretKey = javax.crypto.spec.SecretKeySpec(pbkdf2Key, "AES")
+            val ivSpec = javax.crypto.spec.IvParameterSpec(iv)
+            cipher.init(javax.crypto.Cipher.DECRYPT_MODE, secretKey, ivSpec)
+            val decrypted = cipher.doFinal(ciphertext)
+            
+            // Zlib декомпрессия
+            val inflater = java.util.zip.Inflater()
+            inflater.setInput(decrypted)
+            val outputStream = java.io.ByteArrayOutputStream()
+            val buffer = ByteArray(1024)
+            while (!inflater.finished()) {
+                val count = inflater.inflate(buffer)
+                outputStream.write(buffer, 0, count)
+            }
+            inflater.end()
+            
+            String(outputStream.toByteArray(), Charsets.UTF_8)
+        } catch (e: Exception) {
+            android.util.Log.e("MessageCrypto", "❌ Failed to decrypt with PBKDF2 key", e)
+            null
+        }
+    }
 }

 // Extension functions для конвертации