diff --git a/src/commonMain/kotlin/com/infendro/hash/keccak/Keccak.kt b/src/commonMain/kotlin/com/infendro/hash/keccak/Keccak.kt
index 0c382eb..0365c8c 100644
--- a/src/commonMain/kotlin/com/infendro/hash/keccak/Keccak.kt
+++ b/src/commonMain/kotlin/com/infendro/hash/keccak/Keccak.kt
@@ -6,10 +6,16 @@ import com.infendro.bytearray.toULongArray
 import com.infendro.hash.HashFunction
 import kotlin.math.min
 
-abstract class Keccak internal constructor(
+open class Keccak(
+    override val bytes: Int,
     private val rate: Int,
     private val domain: UByte,
 ) : HashFunction() {
+    init {
+        if (bytes < 1) throw IllegalArgumentException()
+        if (rate !in 8..168) throw IllegalArgumentException()
+    }
+
     override val block: Int
         get() = rate
 
@@ -67,7 +73,7 @@ abstract class Keccak internal constructor(
 
                 addAll(
                     state[i++].toUByteArray(LITTLE_ENDIAN)
-                        .take(min(bytes - size, 8))
+                        .sliceArray(0..<min(bytes - size, 8))
                 )
             }
         }.toUByteArray()
diff --git a/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-224.kt b/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-224.kt
index a62b414..b538483 100644
--- a/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-224.kt
+++ b/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-224.kt
@@ -2,7 +2,4 @@ package com.infendro.hash.keccak.sha3
 
 import com.infendro.hash.keccak.Keccak
 
-object `SHA3-224` : Keccak(144, 0x06U) {
-    override val bytes: Int
-        get() = 28
-}
+object `SHA3-224` : Keccak(28, 144, 0x06U)
diff --git a/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-256.kt b/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-256.kt
index f3f5c56..0980697 100644
--- a/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-256.kt
+++ b/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-256.kt
@@ -2,7 +2,4 @@ package com.infendro.hash.keccak.sha3
 
 import com.infendro.hash.keccak.Keccak
 
-object `SHA3-256` : Keccak(136, 0x06U) {
-    override val bytes: Int
-        get() = 32
-}
+object `SHA3-256` : Keccak(32, 136, 0x06U)
diff --git a/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-384.kt b/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-384.kt
index 07f0367..5ee5f5d 100644
--- a/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-384.kt
+++ b/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-384.kt
@@ -2,7 +2,4 @@ package com.infendro.hash.keccak.sha3
 
 import com.infendro.hash.keccak.Keccak
 
-object `SHA3-384` : Keccak(104, 0x06U) {
-    override val bytes: Int
-        get() = 48
-}
+object `SHA3-384` : Keccak(48, 104, 0x06U)
diff --git a/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-512.kt b/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-512.kt
index 13bb0ee..51efc8d 100644
--- a/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-512.kt
+++ b/src/commonMain/kotlin/com/infendro/hash/keccak/sha3/SHA3-512.kt
@@ -2,7 +2,4 @@ package com.infendro.hash.keccak.sha3
 
 import com.infendro.hash.keccak.Keccak
 
-object `SHA3-512` : Keccak(72, 0x06U) {
-    override val bytes: Int
-        get() = 64
-}
+object `SHA3-512` : Keccak(64, 72, 0x06U)
diff --git a/src/commonMain/kotlin/com/infendro/hash/keccak/shake/SHAKE128.kt b/src/commonMain/kotlin/com/infendro/hash/keccak/shake/SHAKE128.kt
index 0f70d8f..4161707 100644
--- a/src/commonMain/kotlin/com/infendro/hash/keccak/shake/SHAKE128.kt
+++ b/src/commonMain/kotlin/com/infendro/hash/keccak/shake/SHAKE128.kt
@@ -3,5 +3,5 @@ package com.infendro.hash.keccak.shake
 import com.infendro.hash.keccak.Keccak
 
 class SHAKE128(
-    override val bytes: Int,
-) : Keccak(168, 0x1FU)
+    bytes: Int,
+) : Keccak(bytes, 168, 0x1FU)
diff --git a/src/commonMain/kotlin/com/infendro/hash/keccak/shake/SHAKE256.kt b/src/commonMain/kotlin/com/infendro/hash/keccak/shake/SHAKE256.kt
index fa509fb..c18be12 100644
--- a/src/commonMain/kotlin/com/infendro/hash/keccak/shake/SHAKE256.kt
+++ b/src/commonMain/kotlin/com/infendro/hash/keccak/shake/SHAKE256.kt
@@ -3,5 +3,5 @@ package com.infendro.hash.keccak.shake
 import com.infendro.hash.keccak.Keccak
 
 class SHAKE256(
-    override val bytes: Int,
-) : Keccak(136, 0x1FU)
+    bytes: Int,
+) : Keccak(bytes, 136, 0x1FU)