implement seed

src/commonMain/kotlin/com/infendro/random/HMAC.kt

@@ -4,20 +4,24 @@ import com.infendro.bytearray.addAll
 import com.infendro.hash.HashFunction
 
 class HMAC internal constructor(
-    function: HashFunction,
+    private val function: HashFunction,
 ) : PRNG() {
     private val random = Default
     private val hmac = com.infendro.mac.HMAC(function)
-    private var K: ByteArray
-    private var V: ByteArray
+    private lateinit var K: ByteArray
+    private lateinit var V: ByteArray
 
     init {
-        K = ByteArray(function.bytes).also {
-            random.nextBytes(it)
-        }
-        V = ByteArray(function.bytes).also {
-            random.nextBytes(it)
-        }
+        val bytes = random.nextBytes(function.bytes)
+        seed(bytes)
+    }
+
+    override fun seed(
+        seed: ByteArray,
+    ) {
+        K = ByteArray(function.bytes) { 0x00 }
+        V = ByteArray(function.bytes) { 0x01 }
+        reseed(seed)
     }
 
     override fun reseed(

src/commonMain/kotlin/com/infendro/random/PRNG.kt

@@ -5,6 +5,10 @@ import com.infendro.hash.HashFunction
 import kotlin.random.Random
 
 abstract class PRNG : Random() {
+    abstract fun seed(
+        seed: ByteArray,
+    )
+
     abstract fun reseed(
         entropy: ByteArray,
     )