diff --git a/library/xof/api/xof.api b/library/xof/api/xof.api
index 1c0652c..3d50cca 100644
--- a/library/xof/api/xof.api
+++ b/library/xof/api/xof.api
@@ -17,7 +17,7 @@ public abstract class org/kotlincrypto/core/xof/Xof$Reader {
 	public final fun isClosed ()Z
 	public final fun read ([B)I
 	public final fun read ([BII)I
-	protected abstract fun readProtected ([BIIJ)V
+	protected abstract fun readProtected ([BII)I
 	public final fun toString ()Ljava/lang/String;
 	public final fun use (Lkotlin/jvm/functions/Function1;)Ljava/lang/Object;
 }
diff --git a/library/xof/api/xof.klib.api b/library/xof/api/xof.klib.api
index 32ace1c..1295b16 100644
--- a/library/xof/api/xof.klib.api
+++ b/library/xof/api/xof.klib.api
@@ -40,13 +40,14 @@ sealed class <#A: org.kotlincrypto.core.xof/XofAlgorithm> org.kotlincrypto.core.
     abstract inner class Reader { // org.kotlincrypto.core.xof/Xof.Reader|null[0]
         constructor <init>() // org.kotlincrypto.core.xof/Xof.Reader.<init>|<init>(){}[0]
 
-        final var bytesRead // org.kotlincrypto.core.xof/Xof.Reader.bytesRead|{}bytesRead[0]
+        final val bytesRead // org.kotlincrypto.core.xof/Xof.Reader.bytesRead|{}bytesRead[0]
             final fun <get-bytesRead>(): kotlin/Long // org.kotlincrypto.core.xof/Xof.Reader.bytesRead.<get-bytesRead>|<get-bytesRead>(){}[0]
+
         final var isClosed // org.kotlincrypto.core.xof/Xof.Reader.isClosed|{}isClosed[0]
             final fun <get-isClosed>(): kotlin/Boolean // org.kotlincrypto.core.xof/Xof.Reader.isClosed.<get-isClosed>|<get-isClosed>(){}[0]
 
         abstract fun closeProtected() // org.kotlincrypto.core.xof/Xof.Reader.closeProtected|closeProtected(){}[0]
-        abstract fun readProtected(kotlin/ByteArray, kotlin/Int, kotlin/Int, kotlin/Long) // org.kotlincrypto.core.xof/Xof.Reader.readProtected|readProtected(kotlin.ByteArray;kotlin.Int;kotlin.Int;kotlin.Long){}[0]
+        abstract fun readProtected(kotlin/ByteArray, kotlin/Int, kotlin/Int): kotlin/Int // org.kotlincrypto.core.xof/Xof.Reader.readProtected|readProtected(kotlin.ByteArray;kotlin.Int;kotlin.Int){}[0]
         final fun <#A2: kotlin/Any?> use(kotlin/Function1<org.kotlincrypto.core.xof/Xof.Reader<#A>, #A2>): #A2 // org.kotlincrypto.core.xof/Xof.Reader.use|use(kotlin.Function1<org.kotlincrypto.core.xof.Xof.Reader<2:0>,0:0>){0§<kotlin.Any?>}[0]
         final fun close() // org.kotlincrypto.core.xof/Xof.Reader.close|close(){}[0]
         final fun read(kotlin/ByteArray): kotlin/Int // org.kotlincrypto.core.xof/Xof.Reader.read|read(kotlin.ByteArray){}[0]
diff --git a/library/xof/src/commonMain/kotlin/org/kotlincrypto/core/xof/Xof.kt b/library/xof/src/commonMain/kotlin/org/kotlincrypto/core/xof/Xof.kt
index c62a52f..7379c1f 100644
--- a/library/xof/src/commonMain/kotlin/org/kotlincrypto/core/xof/Xof.kt
+++ b/library/xof/src/commonMain/kotlin/org/kotlincrypto/core/xof/Xof.kt
@@ -100,12 +100,22 @@ public sealed class Xof<A: XofAlgorithm>: Algorithm, Copyable<Xof<A>>, Resettabl
      * */
     public abstract inner class Reader {
 
+        private var lo: Int = 0
+        private var hi: Int = 0
+
         /**
-         * The total amount of bytes read for this [Reader] instance
+         * The total amount of bytes read for this [Reader] instance.
+         *
+         * **NOTE:** Only tracks up to a maximum of 2^64 bytes. Actual
+         * output can potentially be larger than that.
          * */
         @get:JvmName("bytesRead")
-        public var bytesRead: Long = 0
-            private set
+        public val bytesRead: Long get() {
+            val lo = lo
+            val hi = hi
+            if (hi == 0) return lo.toLong()
+            return ((hi.toLong() and 0xffffffff) shl 32) or (lo.toLong() and 0xffffffff)
+        }
 
         /**
          * If the reader is closed or not
@@ -159,9 +169,14 @@ public sealed class Xof<A: XofAlgorithm>: Algorithm, Copyable<Xof<A>>, Resettabl
             if (len == 0) return 0
             if (offset < 0 || len < 0 || offset > out.size - len) throw IndexOutOfBoundsException()
 
-            readProtected(out, offset, len, bytesRead)
-            bytesRead += len
-            return len
+            val read = readProtected(out, offset, len)
+
+            // Update read counter
+            val lt0 = lo < 0
+            lo += read
+            if (lt0 && lo >= 0) hi++
+
+            return read
         }
 
         /**
@@ -177,16 +192,14 @@ public sealed class Xof<A: XofAlgorithm>: Algorithm, Copyable<Xof<A>>, Resettabl
             isClosed = true
         }
 
+        protected abstract fun readProtected(out: ByteArray, offset: Int, len: Int): Int
         protected abstract fun closeProtected()
-        protected abstract fun readProtected(out: ByteArray, offset: Int, len: Int, bytesRead: Long)
 
+        /** @suppress */
         public final override fun toString(): String = "${this@Xof}.Reader@${hashCode()}"
     }
 
-    protected abstract fun newReader(): Reader
-
-    public final override fun toString(): String = "Xof[${algorithm()}]@${hashCode()}"
-
+    /** @suppress */
     @InternalKotlinCryptoApi
     public object Utils {
 
@@ -236,4 +249,10 @@ public sealed class Xof<A: XofAlgorithm>: Algorithm, Copyable<Xof<A>>, Resettabl
             return b
         }
     }
+
+    protected abstract fun newReader(): Reader
+
+    /** @suppress */
+    public final override fun toString(): String = "Xof[${algorithm()}]@${hashCode()}"
+
 }
diff --git a/library/xof/src/commonMain/kotlin/org/kotlincrypto/core/xof/XofFactory.kt b/library/xof/src/commonMain/kotlin/org/kotlincrypto/core/xof/XofFactory.kt
index ddc2760..96f968e 100644
--- a/library/xof/src/commonMain/kotlin/org/kotlincrypto/core/xof/XofFactory.kt
+++ b/library/xof/src/commonMain/kotlin/org/kotlincrypto/core/xof/XofFactory.kt
@@ -55,7 +55,7 @@ public abstract class XofFactory<A: XofAlgorithm> public constructor() {
     protected abstract inner class XofDelegate
     @Throws(ClassCastException::class, IllegalArgumentException::class)
     protected constructor(
-        protected val delegate: A
+        protected val delegate: A,
     ) : Xof<A>(),
         Algorithm by delegate,
         Resettable by delegate as Resettable,
@@ -78,9 +78,11 @@ public abstract class XofFactory<A: XofAlgorithm> public constructor() {
          * */
         protected abstract fun newReader(delegateCopy: A): Reader
 
+        /** @suppress */
         public final override fun equals(other: Any?): Boolean {
             return other is XofFactory<*>.XofDelegate && other.delegate == delegate
         }
+        /** @suppress */
         public final override fun hashCode(): Int = delegate.hashCode()
     }
 }