implement common interface

src/commonMain/kotlin/com/infendro/kdf/KDF.kt

@@ -0,0 +1,12 @@
+package com.infendro.kdf
+
+interface KDF {
+    val bytes: Int
+    val bits: Int
+        get() = bytes * 8
+
+    fun hash(
+        value: UByteArray,
+        salt: UByteArray,
+    ): UByteArray
+}