diff --git a/src/commonMain/kotlin/com/infendro/hash/blake2/Blake2b.kt b/src/commonMain/kotlin/com/infendro/hash/blake2/Blake2b.kt
new file mode 100644
index 0000000..9a2295a
--- /dev/null
+++ b/src/commonMain/kotlin/com/infendro/hash/blake2/Blake2b.kt
@@ -0,0 +1,121 @@
+package com.infendro.hash.blake2
+
+import com.infendro.bytearray.ByteOrder
+import com.infendro.bytearray.toUByteArray
+import com.infendro.bytearray.toULongArray
+import com.infendro.hash.HashFunction
+
+class Blake2b(
+    override val bytes: Int,
+) : HashFunction() {
+    init {
+        if (bytes !in 1..64) throw IllegalArgumentException()
+    }
+
+    override val block: Int
+        get() = 128
+
+    private val initial = ulongArrayOf(
+        0x6a09e667f3bcc908UL, 0xbb67ae8584caa73bUL,
+        0x3c6ef372fe94f82bUL, 0xa54ff53a5f1d36f1UL,
+        0x510e527fade682d1UL, 0x9b05688c2b3e6c1fUL,
+        0x1f83d9abfb41bd6bUL, 0x5be0cd19137e2179UL,
+    )
+
+    private val sigma = arrayOf(
+        intArrayOf(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15),
+        intArrayOf(14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3),
+        intArrayOf(11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4),
+        intArrayOf(7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8),
+        intArrayOf(9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13),
+        intArrayOf(2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9),
+        intArrayOf(12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11),
+        intArrayOf(13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10),
+        intArrayOf(6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5),
+        intArrayOf(10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0),
+    )
+
+    override fun hash(value: UByteArray): UByteArray {
+        val h = initial.copyOf()
+        h[0] = h[0] xor (0x01010000UL or bytes.toULong())
+        var t = 0UL
+        val l = value.size.toULong()
+
+        // padding
+        val paddedValue = buildList {
+            addAll(value)
+            if (isEmpty()) add(0x00U)
+            while (size % 128 != 0) {
+                add(0x00U)
+            }
+        }.toUByteArray()
+
+        // compress
+        val blocks = paddedValue
+            .chunked(128) { it.toUByteArray() }
+        for ((i, block) in blocks.withIndex()) {
+            t += minOf(l - t, 128UL)
+
+            val m = block.toULongArray()
+            compress(h, m, t, i == blocks.lastIndex)
+        }
+
+        return h.toUByteArray(ByteOrder.LITTLE_ENDIAN).sliceArray(0..<bytes)
+    }
+
+    private fun compress(
+        h: ULongArray,
+        m: ULongArray,
+        t: ULong,
+        last: Boolean,
+    ) {
+        // initialization
+        val v = ULongArray(16)
+        for (i in 0..<8) v[i] = h[i]
+        for (i in 0..<8) v[i + 8] = initial[i]
+
+        v[12] = v[12] xor t
+        if (last) v[14] = v[14].inv()
+
+        // rounds
+        for (r in 0..<12) {
+            val s = sigma[r % 10]
+
+            // column
+            mix(v, 0, 4, 8, 12, m[s[0]], m[s[1]])
+            mix(v, 1, 5, 9, 13, m[s[2]], m[s[3]])
+            mix(v, 2, 6, 10, 14, m[s[4]], m[s[5]])
+            mix(v, 3, 7, 11, 15, m[s[6]], m[s[7]])
+
+            // diagonal
+            mix(v, 0, 5, 10, 15, m[s[8]], m[s[9]])
+            mix(v, 1, 6, 11, 12, m[s[10]], m[s[11]])
+            mix(v, 2, 7, 8, 13, m[s[12]], m[s[13]])
+            mix(v, 3, 4, 9, 14, m[s[14]], m[s[15]])
+        }
+
+        // finalization
+        for (i in 0..7) {
+            h[i] = h[i] xor v[i] xor v[i + 8]
+        }
+    }
+
+    private fun mix(
+        v: ULongArray,
+        a: Int,
+        b: Int,
+        c: Int,
+        d: Int,
+        x: ULong,
+        y: ULong,
+    ) {
+        v[a] += v[b] + x
+        v[d] = (v[d] xor v[a]).rotateRight(32)
+        v[c] += v[d]
+        v[b] = (v[b] xor v[c]).rotateRight(24)
+        v[a] += v[b] + y
+        v[d] = (v[d] xor v[a]).rotateRight(16)
+        v[c] += v[d]
+        v[b] = (v[b] xor v[c]).rotateRight(63)
+    }
+}
diff --git a/src/commonMain/kotlin/com/infendro/hash/blake2/Blake2s.kt b/src/commonMain/kotlin/com/infendro/hash/blake2/Blake2s.kt
new file mode 100644
index 0000000..f05970e
--- /dev/null
+++ b/src/commonMain/kotlin/com/infendro/hash/blake2/Blake2s.kt
@@ -0,0 +1,121 @@
+package com.infendro.hash.blake2
+
+import com.infendro.bytearray.ByteOrder.LITTLE_ENDIAN
+import com.infendro.bytearray.toUByteArray
+import com.infendro.bytearray.toUIntArray
+import com.infendro.hash.HashFunction
+
+class Blake2s(
+    override val bytes: Int,
+) : HashFunction() {
+    init {
+        if (bytes !in 1..32) throw IllegalArgumentException()
+    }
+
+    override val block: Int
+        get() = 64
+
+    private val initial = uintArrayOf(
+        0x6a09e667U, 0xbb67ae85U,
+        0x3c6ef372U, 0xa54ff53aU,
+        0x510e527fU, 0x9b05688cU,
+        0x1f83d9abU, 0x5be0cd19U,
+    )
+
+    private val sigma = arrayOf(
+        intArrayOf(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15),
+        intArrayOf(14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3),
+        intArrayOf(11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4),
+        intArrayOf(7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8),
+        intArrayOf(9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13),
+        intArrayOf(2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9),
+        intArrayOf(12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11),
+        intArrayOf(13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10),
+        intArrayOf(6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5),
+        intArrayOf(10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0),
+    )
+
+    override fun hash(value: UByteArray): UByteArray {
+        val h = initial.copyOf()
+        h[0] = h[0] xor (0x01010000U or bytes.toUInt())
+        var t = 0U
+        val l = value.size.toULong()
+
+        // padding
+        val paddedValue = buildList {
+            addAll(value)
+            if (isEmpty()) add(0x00U)
+            while (size % 64 != 0) {
+                add(0x00U)
+            }
+        }.toUByteArray()
+
+        // compress
+        val blocks = paddedValue
+            .chunked(64) { it.toUByteArray() }
+        for ((i, block) in blocks.withIndex()) {
+            t += minOf(l - t, 64U).toUInt()
+
+            val m = block.toUIntArray()
+            compress(h, m, t, i == blocks.lastIndex)
+        }
+
+        return h.toUByteArray(LITTLE_ENDIAN).sliceArray(0..<bytes)
+    }
+
+    private fun compress(
+        h: UIntArray,
+        m: UIntArray,
+        t: UInt,
+        last: Boolean,
+    ) {
+        // initialization
+        val v = UIntArray(16)
+        for (i in 0..<8) v[i] = h[i]
+        for (i in 0..<8) v[i + 8] = initial[i]
+
+        v[12] = v[12] xor t
+        if (last) v[14] = v[14].inv()
+
+        // rounds
+        for (r in 0..<10) {
+            val s = sigma[r]
+
+            // column
+            mix(v, 0, 4, 8, 12, m[s[0]], m[s[1]])
+            mix(v, 1, 5, 9, 13, m[s[2]], m[s[3]])
+            mix(v, 2, 6, 10, 14, m[s[4]], m[s[5]])
+            mix(v, 3, 7, 11, 15, m[s[6]], m[s[7]])
+
+            // diagonal
+            mix(v, 0, 5, 10, 15, m[s[8]], m[s[9]])
+            mix(v, 1, 6, 11, 12, m[s[10]], m[s[11]])
+            mix(v, 2, 7, 8, 13, m[s[12]], m[s[13]])
+            mix(v, 3, 4, 9, 14, m[s[14]], m[s[15]])
+        }
+
+        // finalization
+        for (i in 0..7) {
+            h[i] = h[i] xor v[i] xor v[i + 8]
+        }
+    }
+
+    private fun mix(
+        v: UIntArray,
+        a: Int,
+        b: Int,
+        c: Int,
+        d: Int,
+        x: UInt,
+        y: UInt,
+    ) {
+        v[a] += v[b] + x
+        v[d] = (v[d] xor v[a]).rotateRight(16)
+        v[c] += v[d]
+        v[b] = (v[b] xor v[c]).rotateRight(12)
+        v[a] += v[b] + y
+        v[d] = (v[d] xor v[a]).rotateRight(8)
+        v[c] += v[d]
+        v[b] = (v[b] xor v[c]).rotateRight(7)
+    }
+}
diff --git a/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2b-384.kt b/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2b-384.kt
new file mode 100644
index 0000000..e463156
--- /dev/null
+++ b/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2b-384.kt
@@ -0,0 +1,38 @@
+package com.infendro.hash.blake2
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+import kotlin.test.assertEquals
+
+class `Blake2b-384 Test` {
+    val function = Blake2b(48)
+
+    @Test
+    fun `bytes and block`() {
+        assertEquals(48, function.bytes)
+        assertEquals(384, function.bits)
+        assertEquals(128, function.block)
+    }
+
+    @Test
+    fun `empty bytearray`() {
+        val expected = ubyteArrayOf(
+            0xb3U, 0x28U, 0x11U, 0x42U,
+            0x33U, 0x77U, 0xf5U, 0x2dU,
+            0x78U, 0x62U, 0x28U, 0x6eU,
+            0xe1U, 0xa7U, 0x2eU, 0xe5U,
+            0x40U, 0x52U, 0x43U, 0x80U,
+            0xfdU, 0xa1U, 0x72U, 0x4aU,
+            0x6fU, 0x25U, 0xd7U, 0x97U,
+            0x8cU, 0x6fU, 0xd3U, 0x24U,
+            0x4aU, 0x6cU, 0xafU, 0x04U,
+            0x98U, 0x81U, 0x26U, 0x73U,
+            0xc5U, 0xe0U, 0x5eU, 0xf5U,
+            0x83U, 0x82U, 0x51U, 0x00U,
+        )
+        val actual = function.hash(
+            UByteArray(0)
+        )
+        assertContentEquals(expected, actual)
+    }
+}
diff --git a/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2b-512.kt b/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2b-512.kt
new file mode 100644
index 0000000..ee4d83a
--- /dev/null
+++ b/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2b-512.kt
@@ -0,0 +1,42 @@
+package com.infendro.hash.blake2
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+import kotlin.test.assertEquals
+
+class `Blake2b-512 Test` {
+    val function = Blake2b(64)
+
+    @Test
+    fun `bytes and block`() {
+        assertEquals(64, function.bytes)
+        assertEquals(512, function.bits)
+        assertEquals(128, function.block)
+    }
+
+    @Test
+    fun `empty bytearray`() {
+        val expected = ubyteArrayOf(
+            0x78U, 0x6aU, 0x02U, 0xf7U,
+            0x42U, 0x01U, 0x59U, 0x03U,
+            0xc6U, 0xc6U, 0xfdU, 0x85U,
+            0x25U, 0x52U, 0xd2U, 0x72U,
+            0x91U, 0x2fU, 0x47U, 0x40U,
+            0xe1U, 0x58U, 0x47U, 0x61U,
+            0x8aU, 0x86U, 0xe2U, 0x17U,
+            0xf7U, 0x1fU, 0x54U, 0x19U,
+            0xd2U, 0x5eU, 0x10U, 0x31U,
+            0xafU, 0xeeU, 0x58U, 0x53U,
+            0x13U, 0x89U, 0x64U, 0x44U,
+            0x93U, 0x4eU, 0xb0U, 0x4bU,
+            0x90U, 0x3aU, 0x68U, 0x5bU,
+            0x14U, 0x48U, 0xb7U, 0x55U,
+            0xd5U, 0x6fU, 0x70U, 0x1aU,
+            0xfeU, 0x9bU, 0xe2U, 0xceU,
+        )
+        val actual = function.hash(
+            UByteArray(0)
+        )
+        assertContentEquals(expected, actual)
+    }
+}
diff --git a/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2s-224.kt b/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2s-224.kt
new file mode 100644
index 0000000..7fde71b
--- /dev/null
+++ b/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2s-224.kt
@@ -0,0 +1,33 @@
+package com.infendro.hash.blake2
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+import kotlin.test.assertEquals
+
+class `Blake2s-224 Test` {
+    val function = Blake2s(28)
+
+    @Test
+    fun `bytes and block`() {
+        assertEquals(28, function.bytes)
+        assertEquals(224, function.bits)
+        assertEquals(64, function.block)
+    }
+
+    @Test
+    fun `empty bytearray`() {
+        val expected = ubyteArrayOf(
+            0x1fU, 0xa1U, 0x29U, 0x1eU,
+            0x65U, 0x24U, 0x8bU, 0x37U,
+            0xb3U, 0x43U, 0x34U, 0x75U,
+            0xb2U, 0xa0U, 0xddU, 0x63U,
+            0xd5U, 0x4aU, 0x11U, 0xecU,
+            0xc4U, 0xe3U, 0xe0U, 0x34U,
+            0xe7U, 0xbcU, 0x1eU, 0xf4U,
+        )
+        val actual = function.hash(
+            UByteArray(0)
+        )
+        assertContentEquals(expected, actual)
+    }
+}
diff --git a/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2s-256.kt b/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2s-256.kt
new file mode 100644
index 0000000..65e91db
--- /dev/null
+++ b/src/commonTest/kotlin/com/infendro/hash/blake2/Blake2s-256.kt
@@ -0,0 +1,34 @@
+package com.infendro.hash.blake2
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+import kotlin.test.assertEquals
+
+class `Blake2s-256 Test` {
+    val function = Blake2s(32)
+
+    @Test
+    fun `bytes and block`() {
+        assertEquals(32, function.bytes)
+        assertEquals(256, function.bits)
+        assertEquals(64, function.block)
+    }
+
+    @Test
+    fun `empty bytearray`() {
+        val expected = ubyteArrayOf(
+            0x69U, 0x21U, 0x7aU, 0x30U,
+            0x79U, 0x90U, 0x80U, 0x94U,
+            0xe1U, 0x11U, 0x21U, 0xd0U,
+            0x42U, 0x35U, 0x4aU, 0x7cU,
+            0x1fU, 0x55U, 0xb6U, 0x48U,
+            0x2cU, 0xa1U, 0xa5U, 0x1eU,
+            0x1bU, 0x25U, 0x0dU, 0xfdU,
+            0x1eU, 0xd0U, 0xeeU, 0xf9U,
+        )
+        val actual = function.hash(
+            UByteArray(0)
+        )
+        assertContentEquals(expected, actual)
+    }
+}