Better kdf engine implementation

app/src/main/java/com/kunzisoft/keepass/database/element/Database.kt

@@ -340,13 +340,10 @@ class Database {
     var kdfEngine: KdfEngine?
         get() = mDatabaseKDB?.kdfEngine ?: mDatabaseKDBX?.kdfEngine
         set(kdfEngine) {
-            kdfEngine?.let {
+            mDatabaseKDB?.kdfEngine = kdfEngine
-                if (mDatabaseKDBX?.kdfParameters?.uuid != kdfEngine.defaultParameters.uuid)
+            mDatabaseKDBX?.kdfEngine = kdfEngine
-                    mDatabaseKDBX?.kdfParameters = kdfEngine.defaultParameters
+            mDatabaseKDBX?.settingsChanged = DateInstant()
-                numberKeyEncryptionRounds = kdfEngine.defaultKeyRounds
+            dataModifiedSinceLastLoading = true
-                memoryUsage = kdfEngine.defaultMemoryUsage
-                parallelism = kdfEngine.defaultParallelism
-            }
         }
 
     fun getKeyDerivationName(): String {

app/src/main/java/com/kunzisoft/keepass/database/element/database/DatabaseKDB.kt

@@ -44,8 +44,13 @@ class DatabaseKDB : DatabaseVersioned<Int, UUID, GroupKDB, EntryKDB>() {
         EncryptionAlgorithm.Twofish
     )
 
-    override val kdfEngine: KdfEngine
+    override var kdfEngine: KdfEngine?
         get() = kdfAvailableList[0]
+        set(value) {
+            value?.let {
+                numberKeyEncryptionRounds = value.defaultKeyRounds
+            }
+        }
 
     override val kdfAvailableList: List<KdfEngine> = listOf(
         KdfFactory.aesKdf

app/src/main/java/com/kunzisoft/keepass/database/element/database/DatabaseKDBX.kt

@@ -73,6 +73,9 @@ import kotlin.math.min
 
 class DatabaseKDBX : DatabaseVersioned<UUID, UUID, GroupKDBX, EntryKDBX> {
 
+    var hmacKey: ByteArray? = null
+        private set
+
     override var encryptionAlgorithm: EncryptionAlgorithm = EncryptionAlgorithm.AESRijndael
 
     fun setEncryptionAlgorithmFromUUID(uuid: UUID) {
@@ -85,13 +88,24 @@ class DatabaseKDBX : DatabaseVersioned<UUID, UUID, GroupKDBX, EntryKDBX> {
         EncryptionAlgorithm.ChaCha20
     )
 
-    override val kdfEngine: KdfEngine?
+    var kdfParameters: KdfParameters? = null
+
+    override var kdfEngine: KdfEngine?
         get() = try {
             getEngineKDBX4(kdfParameters)
         } catch (unknownKDF: UnknownKDF) {
             Log.i(TAG, "Unable to retrieve KDF engine", unknownKDF)
             null
         }
+        set(value) {
+            value?.let {
+                if (kdfParameters?.uuid != value.defaultParameters.uuid)
+                    kdfParameters = value.defaultParameters
+                numberKeyEncryptionRounds = value.defaultKeyRounds
+                memoryUsage = value.defaultMemoryUsage
+                parallelism = value.defaultParallelism
+            }
+        }
 
     @Throws(UnknownKDF::class)
     fun getEngineKDBX4(kdfParameters: KdfParameters?): KdfEngine {
@@ -113,11 +127,8 @@ class DatabaseKDBX : DatabaseVersioned<UUID, UUID, GroupKDBX, EntryKDBX> {
         KdfFactory.argon2idKdf
     )
 
-    var hmacKey: ByteArray? = null
-        private set
     var compressionAlgorithm = CompressionAlgorithm.GZip
-    var kdfParameters: KdfParameters? = null
+
-    private var numKeyEncRounds: Long = 0
     private val mFieldReferenceEngine = FieldReferencesEngine(this)
     private val mTemplateEngine = TemplateEngineCompatible(this)
 
@@ -311,6 +322,7 @@ class DatabaseKDBX : DatabaseVersioned<UUID, UUID, GroupKDBX, EntryKDBX> {
     override var numberKeyEncryptionRounds: Long
         get() {
             val kdfEngine = kdfEngine
+            var numKeyEncRounds: Long = 0
             if (kdfEngine != null && kdfParameters != null)
                 numKeyEncRounds = kdfEngine.getKeyRounds(kdfParameters!!)
             return numKeyEncRounds
@@ -319,7 +331,6 @@ class DatabaseKDBX : DatabaseVersioned<UUID, UUID, GroupKDBX, EntryKDBX> {
             val kdfEngine = kdfEngine
             if (kdfEngine != null && kdfParameters != null)
                 kdfEngine.setKeyRounds(kdfParameters!!, rounds)
-            numKeyEncRounds = rounds
         }
 
     var memoryUsage: Long

app/src/main/java/com/kunzisoft/keepass/database/element/database/DatabaseVersioned.kt

@@ -51,7 +51,7 @@ abstract class DatabaseVersioned<
     abstract var encryptionAlgorithm: EncryptionAlgorithm
     abstract val availableEncryptionAlgorithms: List<EncryptionAlgorithm>
 
-    abstract val kdfEngine: KdfEngine?
+    abstract var kdfEngine: KdfEngine?
     abstract val kdfAvailableList: List<KdfEngine>
     abstract var numberKeyEncryptionRounds: Long
 

app/src/main/java/com/kunzisoft/keepass/database/merge/DatabaseKDBXMerger.kt

@@ -189,7 +189,7 @@ class DatabaseKDBXMerger(private var database: DatabaseKDBX) {
             database.historyMaxItems = databaseToMerge.historyMaxItems
             database.historyMaxSize = databaseToMerge.historyMaxSize
             database.encryptionAlgorithm = databaseToMerge.encryptionAlgorithm
-            database.kdfParameters = databaseToMerge.kdfParameters
+            database.kdfEngine = databaseToMerge.kdfEngine
             database.numberKeyEncryptionRounds = databaseToMerge.numberKeyEncryptionRounds
             database.memoryUsage = databaseToMerge.memoryUsage
             database.parallelism = databaseToMerge.parallelism