diff --git a/README.md b/README.md
index 332cc31..9cacced 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ repositories {
 }
 
 dependencies {
-    implementation("com.infendro:otp:1.3.0")
+    implementation("com.infendro:otp:1.3.1")
 }
 ```
 
@@ -26,7 +26,7 @@ dependencies {
 fun main() {
     // create TOTP instance
     val totp = TOTP(
-        function = SHA1,
+        function = SHA1(),
         length = 6,
         period = 30.seconds,
     )
diff --git a/build.gradle.kts b/build.gradle.kts
index 267fc8f..1e920ac 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -5,7 +5,7 @@ import com.infendro.plugin.token
 import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
 
 group = "com.infendro"
-version = "1.3.0"
+version = "1.3.1"
 
 plugins {
     alias(libs.plugins.infendro)
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 4215199..07641bb 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -1,9 +1,9 @@
 [versions]
 infendro = "1.1.0"
 kotlin = "2.3.0"
-bytes = "1.4.0"
-hash = "1.6.0"
-mac = "1.4.0"
+bytes = "1.4.2"
+hash = "1.7.0"
+mac = "1.5.0"
 
 [plugins]
 infendro = { id = "com.infendro.plugin", version.ref = "infendro" }
diff --git a/src/commonMain/kotlin/com/infendro/otp/HOTP.kt b/src/commonMain/kotlin/com/infendro/otp/HOTP.kt
index 687e694..429ee48 100644
--- a/src/commonMain/kotlin/com/infendro/otp/HOTP.kt
+++ b/src/commonMain/kotlin/com/infendro/otp/HOTP.kt
@@ -9,7 +9,7 @@ import com.infendro.otp.util.pow
 import kotlin.experimental.and
 
 class HOTP(
-    val function: HashFunction = SHA1,
+    val function: HashFunction = SHA1(),
     val length: Int = 6,
 ) {
     private val hmac = HMAC(function)
@@ -19,14 +19,14 @@ class HOTP(
         return otp(secret, counter)
     }
 
+    fun verify(secret: ByteArray, counter: Long, otp: String): Boolean {
+        return generate(secret, counter) == otp
+    }
+
     private fun otp(secret: ByteArray, counter: Long): String {
         val hash = hmac.hash(secret, counter.toByteArray())
         val offset = (hash.last() and 0xF).toInt()
         val otp = (hash.toInt(offset) and 0x7FFFFFFF) % 10.pow(length)
         return "$otp".padStart(length, '0')
     }
-
-    fun verify(secret: ByteArray, counter: Long, otp: String): Boolean {
-        return generate(secret, counter) == otp
-    }
 }
diff --git a/src/commonMain/kotlin/com/infendro/otp/TOTP.kt b/src/commonMain/kotlin/com/infendro/otp/TOTP.kt
index 1312534..14912ae 100644
--- a/src/commonMain/kotlin/com/infendro/otp/TOTP.kt
+++ b/src/commonMain/kotlin/com/infendro/otp/TOTP.kt
@@ -7,7 +7,7 @@ import kotlin.time.Duration.Companion.seconds
 import kotlin.time.Instant
 
 class TOTP(
-    val function: HashFunction = SHA1,
+    val function: HashFunction = SHA1(),
     val length: Int = 6,
     val period: Duration = 30.seconds,
 ) {
@@ -17,13 +17,13 @@ class TOTP(
         return hotp.generate(secret, counter(instant))
     }
 
+    fun verify(secret: ByteArray, instant: Instant, otp: String): Boolean {
+        return generate(secret, instant) == otp
+    }
+
     private fun counter(instant: Instant): Long {
         val ms = instant.toEpochMilliseconds()
         val d = period.inWholeMilliseconds
         return ms / d
     }
-
-    fun verify(secret: ByteArray, instant: Instant, otp: String): Boolean {
-        return generate(secret, instant) == otp
-    }
 }