diff --git a/gradle.properties b/gradle.properties
index e3ef8c9..54097e2 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,7 +4,7 @@ kotlin.code.style=official
 specifyKotlinAsDependency=false
 
 projectGroup=ru.dbotthepony.kommons
-projectVersion=2.6.0
+projectVersion=2.7.0
 
 guavaDepVersion=33.0.0
 gsonDepVersion=2.8.9
diff --git a/src/main/java/ru/dbotthepony/kommons/util/XXHash32.java b/src/main/java/ru/dbotthepony/kommons/util/XXHash32.java
new file mode 100644
index 0000000..233ae36
--- /dev/null
+++ b/src/main/java/ru/dbotthepony/kommons/util/XXHash32.java
@@ -0,0 +1,168 @@
+package ru.dbotthepony.kommons.util;
+
+import java.security.MessageDigest;
+import java.util.Objects;
+
+/**
+ * Pure Java implementation of XXHash32 hashing function.
+ * <p>
+ * {@link XXHash32#digest()} returns Int encoded as big-endian number.
+ */
+public final class XXHash32 extends MessageDigest {
+	private final int seed;
+
+	private final byte[] mem = new byte[16];
+	private int memIndex;
+
+	private long length;
+
+	private int v0;
+	private int v1;
+	private int v2;
+	private int v3;
+
+	public static final int XXH_PRIME32_1 = 0x9E3779B1;  /*!< 0b10011110001101110111100110110001 */
+	public static final int XXH_PRIME32_2 = 0x85EBCA77;  /*!< 0b10000101111010111100101001110111 */
+	public static final int XXH_PRIME32_3 = 0xC2B2AE3D;  /*!< 0b11000010101100101010111000111101 */
+	public static final int XXH_PRIME32_4 = 0x27D4EB2F;  /*!< 0b00100111110101001110101100101111 */
+	public static final int XXH_PRIME32_5 = 0x165667B1;  /*!< 0b00010110010101100110011110110001 */
+
+	public XXHash32(int seed) {
+		super("XXHash32");
+		this.seed = seed;
+		engineReset();
+	}
+
+	public XXHash32() {
+		this(0);
+	}
+
+	private int round(int acc, int input) {
+		acc += input * XXH_PRIME32_2;
+		acc = Integer.rotateLeft(acc, 13);
+		acc *= XXH_PRIME32_1;
+		return acc;
+	}
+
+	private int load32(int index) {
+		return load32(mem, index);
+	}
+
+	private int load32(byte[] source, int index) {
+		return (((int) source[index]) & 0xFF) |
+			(((int) source[index + 1]) & 0xFF) << 8 |
+			(((int) source[index + 2]) & 0xFF) << 16 |
+			(((int) source[index + 3]) & 0xFF) << 24;
+	}
+
+	private void doRound() {
+		memIndex = 0;
+		v0 = round(v0, load32(0));
+		v1 = round(v1, load32(4));
+		v2 = round(v2, load32(8));
+		v3 = round(v3, load32(12));
+	}
+
+	@Override
+	protected void engineUpdate(byte input) {
+		length++;
+		mem[memIndex++] = input;
+
+		if (memIndex >= 16)
+			doRound();
+	}
+
+	@Override
+	protected void engineUpdate(byte[] input, int offset, int len) {
+		Objects.checkFromIndexSize(offset, input.length, len);
+		if (len == 0) return;
+
+		length += len;
+
+		if (memIndex != 0) {
+			int size = Math.min(16 - memIndex, len);
+			System.arraycopy(input, offset, mem, memIndex, size);
+			memIndex += size;
+			offset += size;
+			len -= size;
+
+			if (memIndex >= 16)
+				doRound();
+		}
+
+		while (len >= 16) {
+			v0 = round(v0, load32(input, offset));
+			v1 = round(v1, load32(input, offset + 4));
+			v2 = round(v2, load32(input, offset + 8));
+			v3 = round(v3, load32(input, offset + 12));
+			offset += 16;
+			len -= 16;
+		}
+
+		if (len != 0) {
+			System.arraycopy(input, offset, mem, memIndex, len);
+			memIndex += len;
+
+			if (memIndex >= 16)
+				doRound();
+		}
+	}
+
+	@Override
+	protected byte[] engineDigest() {
+		int h32;
+
+		if (length >= 16) {
+			h32 = Integer.rotateLeft(v0, 1) +
+				Integer.rotateLeft(v1, 7) +
+				Integer.rotateLeft(v2, 12) +
+				Integer.rotateLeft(v3, 18);
+		} else {
+			h32 = seed + XXH_PRIME32_5;
+		}
+
+		h32 += (int) length;
+
+		int len = memIndex;
+		int index = 0;
+
+		while (len >= 4) {
+			h32 += load32(index) * XXH_PRIME32_3;
+			h32 = Integer.rotateLeft(h32, 17) * XXH_PRIME32_4;
+			index += 4;
+			len -= 4;
+		}
+
+		while (len-- > 0) {
+			h32 += (mem[index++] & 0xFF) * XXH_PRIME32_5;
+			h32 = Integer.rotateLeft(h32, 11) * XXH_PRIME32_1;
+		}
+
+		h32 ^= h32 >>> 15;
+		h32 *= XXH_PRIME32_2;
+		h32 ^= h32 >>> 13;
+		h32 *= XXH_PRIME32_3;
+		h32 ^= h32 >>> 16;
+
+		engineReset();
+
+		byte[] result = new byte[4];
+
+		result[0] = (byte) (h32 >>> 24);
+		result[1] = (byte) (h32 >>> 16);
+		result[2] = (byte) (h32 >>> 8);
+		result[3] = (byte) (h32);
+
+		return result;
+	}
+
+	@Override
+	protected void engineReset() {
+		this.length = 0L;
+		this.memIndex = 0;
+		this.v0 = this.seed + XXH_PRIME32_1 + XXH_PRIME32_2;
+		this.v1 = this.seed + XXH_PRIME32_2;
+		this.v2 = this.seed;
+		this.v3 = this.seed - XXH_PRIME32_1;
+	}
+}
diff --git a/src/main/java/ru/dbotthepony/kommons/util/XXHash64.java b/src/main/java/ru/dbotthepony/kommons/util/XXHash64.java
new file mode 100644
index 0000000..5e41616
--- /dev/null
+++ b/src/main/java/ru/dbotthepony/kommons/util/XXHash64.java
@@ -0,0 +1,194 @@
+package ru.dbotthepony.kommons.util;
+
+import java.security.MessageDigest;
+import java.util.Objects;
+
+/**
+ * Pure Java implementation of XXHash64 hashing function.
+ * <p>
+ * {@link XXHash64#digest()} returns Long encoded as big-endian number.
+ */
+public final class XXHash64 extends MessageDigest {
+	private final long seed;
+	private final byte[] mem = new byte[32];
+	private int memIndex;
+
+	private long length;
+
+	private long v0;
+	private long v1;
+	private long v2;
+	private long v3;
+
+	public static final long XXH_PRIME64_1 = 0x9E3779B185EBCA87L;  /*!< 0b1001111000110111011110011011000110000101111010111100101010000111 */
+	public static final long XXH_PRIME64_2 = 0xC2B2AE3D27D4EB4FL;  /*!< 0b1100001010110010101011100011110100100111110101001110101101001111 */
+	public static final long XXH_PRIME64_3 = 0x165667B19E3779F9L;  /*!< 0b0001011001010110011001111011000110011110001101110111100111111001 */
+	public static final long XXH_PRIME64_4 = 0x85EBCA77C2B2AE63L;  /*!< 0b1000010111101011110010100111011111000010101100101010111001100011 */
+	public static final long XXH_PRIME64_5 = 0x27D4EB2F165667C5L;  /*!< 0b0010011111010100111010110010111100010110010101100110011111000101 */
+
+	public XXHash64(long seed) {
+		super("XXHash64");
+		this.seed = seed;
+		engineReset();
+	}
+
+	public XXHash64() {
+		this(0);
+	}
+
+	private long load64(int index) {
+		return load64(mem, index);
+	}
+
+	private long load64(byte[] source, int index) {
+		return (((long) source[index]) & 0xFFL) |
+			(((long) source[index + 1]) & 0xFFL) << 8 |
+			(((long) source[index + 2]) & 0xFFL) << 16 |
+			(((long) source[index + 3]) & 0xFFL) << 24 |
+			(((long) source[index + 4]) & 0xFFL) << 32 |
+			(((long) source[index + 5]) & 0xFFL) << 40 |
+			(((long) source[index + 6]) & 0xFFL) << 48 |
+			(((long) source[index + 7]) & 0xFFL) << 56;
+	}
+
+	private long load32(int index) {
+		return (((long) mem[index]) & 0xFFL) |
+			(((long) mem[index + 1]) & 0xFFL) << 8 |
+			(((long) mem[index + 2]) & 0xFFL) << 16 |
+			(((long) mem[index + 3]) & 0xFFL) << 24;
+	}
+
+	private long round(long acc, long input) {
+		acc += input * XXH_PRIME64_2;
+		acc = Long.rotateLeft(acc, 31);
+		return acc * XXH_PRIME64_1;
+	}
+
+	private long mergeRound(long acc, long val) {
+		val = round(0L, val);
+		acc ^= val;
+		return acc * XXH_PRIME64_1 + XXH_PRIME64_4;
+	}
+
+	private void doRound() {
+		memIndex = 0;
+		v0 = round(v0, load64(0));
+		v1 = round(v1, load64(8));
+		v2 = round(v2, load64(16));
+		v3 = round(v3, load64(24));
+	}
+
+	@Override
+	protected void engineUpdate(byte input) {
+		length++;
+		mem[memIndex++] = input;
+
+		if (memIndex >= 32)
+			doRound();
+	}
+
+	@Override
+	protected void engineUpdate(byte[] input, int offset, int len) {
+		Objects.checkFromIndexSize(offset, input.length, len);
+		if (len == 0) return;
+
+		length += len;
+
+		if (memIndex != 0) {
+			int size = Math.min(32 - memIndex, len);
+			System.arraycopy(input, offset, mem, memIndex, size);
+			memIndex += size;
+			offset += size;
+			len -= size;
+
+			if (memIndex >= 32)
+				doRound();
+		}
+
+		while (len >= 32) {
+			v0 = round(v0, load64(input, offset));
+			v1 = round(v1, load64(input, offset + 8));
+			v2 = round(v2, load64(input, offset + 16));
+			v3 = round(v3, load64(input, offset + 24));
+			offset += 32;
+			len -= 32;
+		}
+
+		if (len != 0) {
+			System.arraycopy(input, offset, mem, memIndex, len);
+			memIndex += len;
+
+			if (memIndex >= 32)
+				doRound();
+		}
+	}
+
+	@Override
+	protected byte[] engineDigest() {
+		long h64;
+
+		if (length >= 32L) {
+			h64 = Long.rotateLeft(v0, 1) + Long.rotateLeft(v1, 7) + Long.rotateLeft(v2, 12) + Long.rotateLeft(v3, 18);
+			h64 = mergeRound(h64, v0);
+			h64 = mergeRound(h64, v1);
+			h64 = mergeRound(h64, v2);
+			h64 = mergeRound(h64, v3);
+		} else {
+			h64 = seed + XXH_PRIME64_5;
+		}
+
+		h64 += length;
+		int len = (int) (length & 31L);
+		int index = 0;
+
+		while (len >= 8) {
+			h64 ^= round(0L, load64(index));
+			h64 = Long.rotateLeft(h64, 27) * XXH_PRIME64_1 + XXH_PRIME64_4;
+			index += 8;
+			len -= 8;
+		}
+
+		if (len >= 4) {
+			h64 ^= load32(index) * XXH_PRIME64_1;
+			h64 = Long.rotateLeft(h64, 23) * XXH_PRIME64_2 + XXH_PRIME64_3;
+			index += 4;
+			len -= 4;
+		}
+
+		while (len-- > 0) {
+			h64 ^= (mem[index++] & 0xFFL) * XXH_PRIME64_5;
+			h64 = Long.rotateLeft(h64, 11) * XXH_PRIME64_1;
+		}
+
+		h64 ^= h64 >>> 33;
+		h64 *= XXH_PRIME64_2;
+		h64 ^= h64 >>> 29;
+		h64 *= XXH_PRIME64_3;
+		h64 ^= h64 >>> 32;
+
+		engineReset();
+
+		byte[] result = new byte[8];
+
+		result[7] = (byte) h64;
+		result[6] = (byte) (h64 >>> 8);
+		result[5] = (byte) (h64 >>> 16);
+		result[4] = (byte) (h64 >>> 24);
+		result[3] = (byte) (h64 >>> 32);
+		result[2] = (byte) (h64 >>> 40);
+		result[1] = (byte) (h64 >>> 48);
+		result[0] = (byte) (h64 >>> 56);
+
+		return result;
+	}
+
+	@Override
+	protected void engineReset() {
+		this.length = 0L;
+		this.memIndex = 0;
+		this.v0 = this.seed + XXH_PRIME64_1 + XXH_PRIME64_2;
+		this.v1 = this.seed + XXH_PRIME64_2;
+		this.v2 = this.seed;
+		this.v3 = this.seed - XXH_PRIME64_1;
+	}
+}
diff --git a/src/main/kotlin/ru/dbotthepony/kommons/util/HashUtils.kt b/src/main/kotlin/ru/dbotthepony/kommons/util/HashUtils.kt
new file mode 100644
index 0000000..942397e
--- /dev/null
+++ b/src/main/kotlin/ru/dbotthepony/kommons/util/HashUtils.kt
@@ -0,0 +1,49 @@
+package ru.dbotthepony.kommons.util
+
+fun xxhash64(data: String, seed: Long = 0L): ByteArray {
+	val digest = XXHash64(seed)
+	digest.update(data.toByteArray())
+	return digest.digest()
+}
+
+fun xxhash32(data: String, seed: Int = 0): ByteArray {
+	val digest = XXHash32(seed)
+	digest.update(data.toByteArray())
+	return digest.digest()
+}
+
+fun xxhash64(data: ByteArray, seed: Long = 0L): ByteArray {
+	val digest = XXHash64(seed)
+	digest.update(data)
+	return digest.digest()
+}
+
+fun xxhash32(data: ByteArray, seed: Int = 0): ByteArray {
+	val digest = XXHash32(seed)
+	digest.update(data)
+	return digest.digest()
+}
+
+fun xxhash64(data: ByteArray, offset: Int, length: Int, seed: Long = 0L): ByteArray {
+	val digest = XXHash64(seed)
+	digest.update(data, offset, length)
+	return digest.digest()
+}
+
+fun xxhash32(data: ByteArray, offset: Int, length: Int, seed: Int = 0): ByteArray {
+	val digest = XXHash32(seed)
+	digest.update(data, offset, length)
+	return digest.digest()
+}
+
+fun digest2string(hash: ByteArray): String {
+	val builder = StringBuilder(hash.size * 2)
+
+	for (b in hash) {
+		val s = (b.toInt() and 0xFF).toString(16)
+		if (s.length == 1) builder.append("0")
+		builder.append(s)
+	}
+
+	return builder.toString()
+}
diff --git a/src/test/kotlin/ru/dbotthepony/kommons/test/BTreeDB6Tests.kt b/src/test/kotlin/ru/dbotthepony/kommons/test/BTreeDB6Tests.kt
index d92c729..6cb84fe 100644
--- a/src/test/kotlin/ru/dbotthepony/kommons/test/BTreeDB6Tests.kt
+++ b/src/test/kotlin/ru/dbotthepony/kommons/test/BTreeDB6Tests.kt
@@ -14,16 +14,16 @@ object BTreeDB6Tests {
 	fun test() {
 		val file = File("dbtest.bdb")
 		if (file.exists()) file.delete()
-		val create = BTreeDB6.create(file, 4096, sync = false)
+		val create = BTreeDB6.create(file, 128, sync = false)
 
-		for (i in 0 .. 8000) {
+		for (i in 0 .. 200) {
 			val s = "This is key $i"
 			val k = ByteKey("This is key $i")
 			create.write(k, s.toByteArray())
 			assertEquals(s, String(create.read(k).get()))
 		}
 
-		for (i in 0 .. 8000) {
+		for (i in 0 .. 200) {
 			val s = "This is key $i"
 			val k = ByteKey("This is key $i")
 			assertEquals(s, String(create.read(k).get()))
diff --git a/src/test/kotlin/ru/dbotthepony/kommons/test/HashingTests.kt b/src/test/kotlin/ru/dbotthepony/kommons/test/HashingTests.kt
new file mode 100644
index 0000000..249a407
--- /dev/null
+++ b/src/test/kotlin/ru/dbotthepony/kommons/test/HashingTests.kt
@@ -0,0 +1,23 @@
+package ru.dbotthepony.kommons.test
+
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Test
+import ru.dbotthepony.kommons.util.XXHash32
+import ru.dbotthepony.kommons.util.XXHash64
+import ru.dbotthepony.kommons.util.digest2string
+import kotlin.test.assertEquals
+
+object HashingTests {
+	@Test
+	@DisplayName("xxHash64 implementation")
+	fun xxHash64() {
+		val str = "Nobody inspects the spammish repetition"
+		val hasher = XXHash32()
+		hasher.update(str.toByteArray())
+		assertEquals("e2293b2f", digest2string(hasher.digest()))
+
+		val hasher2 = XXHash64()
+		hasher2.update(str.toByteArray())
+		assertEquals("fbcea83c8a378bf1", digest2string(hasher2.digest()))
+	}
+}