From 9db4ee21a0c06ab3457a82d028f9c425e9c34fda Mon Sep 17 00:00:00 2001
From: Infendro <infendro@noreply.infendro.com>
Date: Mon, 10 Nov 2025 14:54:19 +0100
Subject: [PATCH] implement common class, refactor HMAC

---
 build.gradle.kts                              |  5 ++
 gradle/libs.versions.toml                     |  4 +-
 .../kotlin/com/infendro/mac/HMAC.kt           | 46 +++++++------------
 src/commonMain/kotlin/com/infendro/mac/MAC.kt | 14 ++++++
 4 files changed, 39 insertions(+), 30 deletions(-)
 create mode 100644 src/commonMain/kotlin/com/infendro/mac/MAC.kt

diff --git a/build.gradle.kts b/build.gradle.kts
index 4488ed1..e229a86 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -21,8 +21,13 @@ kotlin {
     sourceSets {
         commonMain.dependencies {
             implementation(libs.hash)
+            implementation(libs.bytearray)
         }
     }
+
+    compilerOptions {
+        freeCompilerArgs.add("-opt-in=kotlin.ExperimentalUnsignedTypes")
+    }
 }
 
 publishing {
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index efa0555..b02d28d 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -1,9 +1,11 @@
 [versions]
 kotlin = "2.1.20"
-hash = "1.2.2"
+hash = "1.3.1"
+bytearray = "1.2.0"
 
 [plugins]
 multiplatform = { id = "org.jetbrains.kotlin.multiplatform", version.ref = "kotlin" }
 
 [libraries]
 hash = { module = "com.infendro:hash", version.ref = "hash" }
+bytearray = { module = "com.infendro:bytearray", version.ref = "bytearray" }
diff --git a/src/commonMain/kotlin/com/infendro/mac/HMAC.kt b/src/commonMain/kotlin/com/infendro/mac/HMAC.kt
index 8645f95..b814673 100644
--- a/src/commonMain/kotlin/com/infendro/mac/HMAC.kt
+++ b/src/commonMain/kotlin/com/infendro/mac/HMAC.kt
@@ -1,45 +1,33 @@
 package com.infendro.mac
 
-import com.infendro.hash.*
-import kotlin.experimental.xor
+import com.infendro.bytearray.padEnd
+import com.infendro.hash.HashFunction
 
 class HMAC(
     val function: HashFunction,
-) {
-    val block: Int
-        get() = when (function) {
-            MD5, SHA1, SHA224, SHA256 -> 64
-            SHA384, SHA512 -> 128
-        }
+) : MAC() {
+    override val bytes: Int
+        get() = function.bytes
 
-    fun hash(
-        key: ByteArray,
-        value: ByteArray,
-    ): ByteArray {
+    override fun hash(
+        key: UByteArray,
+        value: UByteArray,
+    ): UByteArray {
         val paddedKey = pad(key)
 
-        val innerKey = paddedKey.map { it xor 0x36 }.toByteArray()
-        val outerKey = paddedKey.map { it xor 0x5C }.toByteArray()
+        val innerKey = paddedKey.map { it xor 0x36U }.toUByteArray()
+        val outerKey = paddedKey.map { it xor 0x5CU }.toUByteArray()
 
         return function.hash(outerKey + function.hash(innerKey + value))
     }
 
     private fun pad(
-        key: ByteArray,
-    ): ByteArray {
-        if (key.size > block) {
-            return function.hash(key)
+        key: UByteArray,
+    ): UByteArray {
+        return when {
+            key.size > function.block -> function.hash(key)
+            key.size < function.block -> key.padEnd(function.block, 0x00U)
+            else -> key
         }
-
-        if (key.size < block) {
-            return buildList {
-                addAll(key.toList())
-                repeat(block - size) {
-                    add(0x00)
-                }
-            }.toByteArray()
-        }
-
-        return key
     }
 }
diff --git a/src/commonMain/kotlin/com/infendro/mac/MAC.kt b/src/commonMain/kotlin/com/infendro/mac/MAC.kt
new file mode 100644
index 0000000..2f44ba2
--- /dev/null
+++ b/src/commonMain/kotlin/com/infendro/mac/MAC.kt
@@ -0,0 +1,14 @@
+package com.infendro.mac
+
+abstract class MAC {
+    abstract val bytes: Int
+
+    @Suppress("UNUSED")
+    val bits: Int
+        get() = bytes * 8
+
+    abstract fun hash(
+        key: UByteArray,
+        value: UByteArray,
+    ): UByteArray
+}