diff --git a/nearby/service/java/com/android/server/nearby/presence/DataElementHeader.java b/nearby/service/java/com/android/server/nearby/presence/DataElementHeader.java
new file mode 100644
index 0000000..ae4a728
--- /dev/null
+++ b/nearby/service/java/com/android/server/nearby/presence/DataElementHeader.java
@@ -0,0 +1,266 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.presence;
+
+import android.annotation.Nullable;
+import android.nearby.BroadcastRequest;
+import android.nearby.DataElement;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.util.Preconditions;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+
+import javax.annotation.Nonnull;
+
+/**
+ * Represents a data element header in Nearby Presence.
+ * Each header has 3 parts: tag, length and style.
+ * Tag: 1 bit (MSB at each byte). 1 for extending, which means there will be more bytes after
+ * the current one for the header.
+ * Length: The total length of a Data Element field. Length is up to 127 and is limited within
+ * the entire first byte in the header. (7 bits, MSB is the tag).
+ * Type: Represents {@link DataElement.DataType}. There is no limit for the type number.
+ *
+ * @hide
+ */
+public class DataElementHeader {
+    // Each Data reserved MSB for tag.
+    static final int TAG_BITMASK = 0b10000000;
+    static final int TAG_OFFSET = 7;
+
+    // If the header is only 1 byte, it has the format: 0b0LLLTTTT. (L for length, T for type.)
+    static final int SINGLE_AVAILABLE_LENGTH_BIT = 3;
+    static final int SINGLE_AVAILABLE_TYPE_BIT = 4;
+    static final int SINGLE_LENGTH_BITMASK = 0b01110000;
+    static final int SINGLE_LENGTH_OFFSET = SINGLE_AVAILABLE_TYPE_BIT;
+    static final int SINGLE_TYPE_BITMASK = 0b00001111;
+
+    // If there are multiple data element headers.
+    // First byte is always the length.
+    static final int MULTIPLE_LENGTH_BYTE = 1;
+    // Each byte reserves MSB for tag.
+    static final int MULTIPLE_BITMASK = 0b01111111;
+
+    @BroadcastRequest.BroadcastVersion
+    private final int mVersion;
+    @DataElement.DataType
+    private final int mDataType;
+    private final int mDataLength;
+
+    DataElementHeader(@BroadcastRequest.BroadcastVersion int version,
+            @DataElement.DataType int dataType, int dataLength) {
+        Preconditions.checkArgument(version == BroadcastRequest.PRESENCE_VERSION_V1,
+                "DataElementHeader is only supported in V1.");
+        Preconditions.checkArgument(dataLength >= 0, "Length should not be negative.");
+        Preconditions.checkArgument(dataLength < (1 << TAG_OFFSET),
+                "Data element should be equal or shorter than 128.");
+
+        this.mVersion = version;
+        this.mDataType = dataType;
+        this.mDataLength = dataLength;
+    }
+
+    /**
+     * The total type of the data element.
+     */
+    @DataElement.DataType
+    public int getDataType() {
+        return mDataType;
+    }
+
+    /**
+     * The total length of a Data Element field.
+     */
+    public int getDataLength() {
+        return mDataLength;
+    }
+
+    /** Serialize a {@link DataElementHeader} object into bytes. */
+    public byte[] toBytes() {
+        Preconditions.checkState(mVersion == BroadcastRequest.PRESENCE_VERSION_V1,
+                "DataElementHeader is only supported in V1.");
+        // Only 1 byte needed for the header
+        if (mDataType < (1 << SINGLE_AVAILABLE_TYPE_BIT)
+                && mDataLength < (1 << SINGLE_AVAILABLE_LENGTH_BIT)) {
+            return new byte[]{createSingleByteHeader(mDataType, mDataLength)};
+        }
+
+        return createMultipleBytesHeader(mDataType, mDataLength);
+    }
+
+    /** Creates a {@link DataElementHeader} object from bytes. */
+    @Nullable
+    public static DataElementHeader fromBytes(@BroadcastRequest.BroadcastVersion int version,
+            @Nonnull byte[] bytes) {
+        Objects.requireNonNull(bytes, "Data parsed in for DataElement should not be null.");
+
+        if (bytes.length == 0) {
+            return null;
+        }
+
+        if (bytes.length == 1) {
+            if (isExtending(bytes[0])) {
+                throw new IllegalArgumentException("The header is not complete.");
+            }
+            return new DataElementHeader(BroadcastRequest.PRESENCE_VERSION_V1,
+                    getTypeSingleByte(bytes[0]), getLengthSingleByte(bytes[0]));
+        }
+
+        // The first byte should be length and there should be at least 1 more byte following to
+        // represent type.
+        // The last header byte's MSB should be 0.
+        if (!isExtending(bytes[0]) || isExtending(bytes[bytes.length - 1])) {
+            throw new IllegalArgumentException("The header format is wrong.");
+        }
+
+        return new DataElementHeader(version,
+                getTypeMultipleBytes(Arrays.copyOfRange(bytes, 1, bytes.length)),
+                getHeaderValue(bytes[0]));
+    }
+
+    /** Creates a header based on type and length.
+     * This is used when the type is <= 16 and length is <= 7. */
+    static byte createSingleByteHeader(int type, int length) {
+        return (byte) (convertTag(/* extend= */ false)
+                | convertLengthSingleByte(length)
+                | convertTypeSingleByte(type));
+    }
+
+    /** Creates a header based on type and length.
+     * This is used when the type is > 16 or length is > 7. */
+    static byte[] createMultipleBytesHeader(int type, int length) {
+        List<Byte> typeIntList = convertTypeMultipleBytes(type);
+        byte[] res = new byte[typeIntList.size() + MULTIPLE_LENGTH_BYTE];
+        int index = 0;
+        res[index++] = convertLengthMultipleBytes(length);
+
+        for (int typeInt : typeIntList) {
+            res[index++] = (byte) typeInt;
+        }
+        return res;
+    }
+
+    /** Constructs a Data Element header with length indicated in byte format.
+     * The most significant bit is the tag, 2- 4 bits are the length, 5 - 8 bits are the type.
+     */
+    @VisibleForTesting
+    static int convertLengthSingleByte(int length) {
+        Preconditions.checkArgument(length >= 0, "Length should not be negative.");
+        Preconditions.checkArgument(length < (1 << SINGLE_AVAILABLE_LENGTH_BIT),
+                "In single Data Element header, length should be shorter than 8.");
+        return (length << SINGLE_LENGTH_OFFSET) & SINGLE_LENGTH_BITMASK;
+    }
+
+    /** Constructs a Data Element header with type indicated in byte format.
+     * The most significant bit is the tag, 2- 4 bits are the length, 5 - 8 bits are the type.
+     */
+    @VisibleForTesting
+    static int convertTypeSingleByte(int type) {
+        Preconditions.checkArgument(type >= 0, "Type should not be negative.");
+        Preconditions.checkArgument(type < (1 << SINGLE_AVAILABLE_TYPE_BIT),
+                "In single Data Element header, type should be smaller than 16.");
+
+        return type & SINGLE_TYPE_BITMASK;
+    }
+
+    /**
+     * Gets the length of Data Element from the header. (When there is only 1 byte of header)
+     */
+    static int getLengthSingleByte(byte header) {
+        Preconditions.checkArgument(!isExtending(header),
+                "Cannot apply this method for the extending header.");
+        return (header & SINGLE_LENGTH_BITMASK) >> SINGLE_LENGTH_OFFSET;
+    }
+
+    /**
+     * Gets the type of Data Element from the header. (When there is only 1 byte of header)
+     */
+    static int getTypeSingleByte(byte header) {
+        Preconditions.checkArgument(!isExtending(header),
+                "Cannot apply this method for the extending header.");
+        return header & SINGLE_TYPE_BITMASK;
+    }
+
+    /** Creates a DE(data element) header based on length.
+     * This is used when header is more than 1 byte. The first byte is always the length.
+     */
+    static byte convertLengthMultipleBytes(int length) {
+        Preconditions.checkArgument(length < (1 << TAG_OFFSET),
+                "Data element should be equal or shorter than 128.");
+        return (byte) (convertTag(/* extend= */ true) | (length & MULTIPLE_BITMASK));
+    }
+
+    /** Creates a DE(data element) header based on type.
+     * This is used when header is more than 1 byte. The first byte is always the length.
+     */
+    @VisibleForTesting
+    static List<Byte> convertTypeMultipleBytes(int type) {
+        List<Byte> typeBytes = new ArrayList<>();
+        while (type > 0) {
+            byte current = (byte) (type & MULTIPLE_BITMASK);
+            type = type >> TAG_OFFSET;
+            typeBytes.add(current);
+        }
+
+        Collections.reverse(typeBytes);
+        int size = typeBytes.size();
+        // The last byte's MSB should be 0.
+        for (int i = 0; i < size - 1; i++) {
+            typeBytes.set(i, (byte) (convertTag(/* extend= */ true) | typeBytes.get(i)));
+        }
+        return typeBytes;
+    }
+
+    /** Creates a DE(data element) header based on type.
+     * This is used when header is more than 1 byte. The first byte is always the length.
+     * Uses Integer when doing bit operation to avoid error.
+     */
+    @VisibleForTesting
+    static int getTypeMultipleBytes(byte[] typeByteArray) {
+        int type = 0;
+        int size = typeByteArray.length;
+        for (int i = 0; i < size; i++) {
+            type = (type << TAG_OFFSET) | getHeaderValue(typeByteArray[i]);
+        }
+        return type;
+    }
+
+    /** Gets the integer value of the 7 bits in the header. (The MSB is tag) */
+    @VisibleForTesting
+    static int getHeaderValue(byte header) {
+        return (header & MULTIPLE_BITMASK);
+    }
+
+    /** Sets the MSB of the header byte. If this is the last byte of headers, MSB is 0.
+     * If there are at least header following, the MSB is 1.
+     */
+    @VisibleForTesting
+    static byte convertTag(boolean extend) {
+        return (byte) (extend ? 0b10000000 : 0b00000000);
+    }
+
+    /** Returns {@code true} if there are at least 1 byte of header after the current one. */
+    @VisibleForTesting
+    static boolean isExtending(byte header) {
+        return (header & TAG_BITMASK) != 0;
+    }
+}
diff --git a/nearby/tests/unit/src/com/android/server/nearby/presence/DataElementHeaderTest.java b/nearby/tests/unit/src/com/android/server/nearby/presence/DataElementHeaderTest.java
new file mode 100644
index 0000000..e186709
--- /dev/null
+++ b/nearby/tests/unit/src/com/android/server/nearby/presence/DataElementHeaderTest.java
@@ -0,0 +1,179 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.nearby.presence;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.junit.Assert.assertThrows;
+
+import android.nearby.BroadcastRequest;
+
+import org.junit.Test;
+
+import java.util.List;
+
+/**
+ * Unit test for {@link DataElementHeader}.
+ */
+public class DataElementHeaderTest {
+
+    private static final int VERSION = BroadcastRequest.PRESENCE_VERSION_V1;
+
+    @Test
+    public void test_illegalLength() {
+        assertThrows(IllegalArgumentException.class,
+                () -> new DataElementHeader(VERSION, 12, 128));
+    }
+
+    @Test
+    public void test_singeByteConversion() {
+        DataElementHeader header = new DataElementHeader(VERSION, 12, 3);
+        byte[] bytes = header.toBytes();
+        assertThat(bytes).isEqualTo(new byte[]{(byte) 0b00111100});
+
+        DataElementHeader afterConversionHeader = DataElementHeader.fromBytes(VERSION, bytes);
+        assertThat(afterConversionHeader.getDataLength()).isEqualTo(3);
+        assertThat(afterConversionHeader.getDataType()).isEqualTo(12);
+    }
+
+    @Test
+    public void test_multipleBytesConversion() {
+        DataElementHeader header = new DataElementHeader(VERSION, 6, 100);
+        DataElementHeader afterConversionHeader =
+                DataElementHeader.fromBytes(VERSION, header.toBytes());
+        assertThat(afterConversionHeader.getDataLength()).isEqualTo(100);
+        assertThat(afterConversionHeader.getDataType()).isEqualTo(6);
+    }
+
+    @Test
+    public void test_fromBytes() {
+        // Single byte case.
+        byte[] singleByte = new byte[]{(byte) 0b01011101};
+        DataElementHeader singeByteHeader = DataElementHeader.fromBytes(VERSION, singleByte);
+        assertThat(singeByteHeader.getDataLength()).isEqualTo(5);
+        assertThat(singeByteHeader.getDataType()).isEqualTo(13);
+
+        // Two bytes case.
+        byte[] twoBytes = new byte[]{(byte) 0b11011101, (byte) 0b01011101};
+        DataElementHeader twoBytesHeader = DataElementHeader.fromBytes(VERSION, twoBytes);
+        assertThat(twoBytesHeader.getDataLength()).isEqualTo(93);
+        assertThat(twoBytesHeader.getDataType()).isEqualTo(93);
+
+        // Three bytes case.
+        byte[] threeBytes = new byte[]{(byte) 0b11011101, (byte) 0b11111111, (byte) 0b01011101};
+        DataElementHeader threeBytesHeader = DataElementHeader.fromBytes(VERSION, threeBytes);
+        assertThat(threeBytesHeader.getDataLength()).isEqualTo(93);
+        assertThat(threeBytesHeader.getDataType()).isEqualTo(16349);
+
+        // Four bytes case.
+        byte[] fourBytes = new byte[]{
+                (byte) 0b11011101, (byte) 0b11111111, (byte) 0b11111111, (byte) 0b01011101};
+
+        DataElementHeader fourBytesHeader = DataElementHeader.fromBytes(VERSION, fourBytes);
+        assertThat(fourBytesHeader.getDataLength()).isEqualTo(93);
+        assertThat(fourBytesHeader.getDataType()).isEqualTo(2097117);
+    }
+
+    @Test
+    public void test_fromBytesIllegal_singleByte() {
+        assertThrows(IllegalArgumentException.class,
+                () -> DataElementHeader.fromBytes(VERSION, new byte[]{(byte) 0b11011101}));
+    }
+
+    @Test
+    public void test_fromBytesIllegal_twoBytes_wrongFirstByte() {
+        assertThrows(IllegalArgumentException.class,
+                () -> DataElementHeader.fromBytes(VERSION,
+                        new byte[]{(byte) 0b01011101, (byte) 0b01011101}));
+    }
+
+    @Test
+    public void test_fromBytesIllegal_twoBytes_wrongLastByte() {
+        assertThrows(IllegalArgumentException.class,
+                () -> DataElementHeader.fromBytes(VERSION,
+                        new byte[]{(byte) 0b11011101, (byte) 0b11011101}));
+    }
+
+    @Test
+    public void test_fromBytesIllegal_threeBytes() {
+        assertThrows(IllegalArgumentException.class,
+                () -> DataElementHeader.fromBytes(VERSION,
+                        new byte[]{(byte) 0b11011101, (byte) 0b11011101, (byte) 0b11011101}));
+    }
+
+    @Test
+    public void test_multipleBytesConversion_largeNumber() {
+        DataElementHeader header = new DataElementHeader(VERSION, 22213546, 66);
+        DataElementHeader afterConversionHeader =
+                DataElementHeader.fromBytes(VERSION, header.toBytes());
+        assertThat(afterConversionHeader.getDataLength()).isEqualTo(66);
+        assertThat(afterConversionHeader.getDataType()).isEqualTo(22213546);
+    }
+
+    @Test
+    public void test_isExtending() {
+        assertThat(DataElementHeader.isExtending((byte) 0b10000100)).isTrue();
+        assertThat(DataElementHeader.isExtending((byte) 0b01110100)).isFalse();
+        assertThat(DataElementHeader.isExtending((byte) 0b00000000)).isFalse();
+    }
+
+    @Test
+    public void test_convertTag() {
+        assertThat(DataElementHeader.convertTag(true)).isEqualTo((byte) 128);
+        assertThat(DataElementHeader.convertTag(false)).isEqualTo(0);
+    }
+
+    @Test
+    public void test_getHeaderValue() {
+        assertThat(DataElementHeader.getHeaderValue((byte) 0b10000100)).isEqualTo(4);
+        assertThat(DataElementHeader.getHeaderValue((byte) 0b00000100)).isEqualTo(4);
+        assertThat(DataElementHeader.getHeaderValue((byte) 0b11010100)).isEqualTo(84);
+        assertThat(DataElementHeader.getHeaderValue((byte) 0b01010100)).isEqualTo(84);
+    }
+
+    @Test
+    public void test_convertTypeMultipleIntList() {
+        List<Byte> list = DataElementHeader.convertTypeMultipleBytes(128);
+        assertThat(list.size()).isEqualTo(2);
+        assertThat(list.get(0)).isEqualTo((byte) 0b10000001);
+        assertThat(list.get(1)).isEqualTo((byte) 0b00000000);
+
+        List<Byte> list2 = DataElementHeader.convertTypeMultipleBytes(10);
+        assertThat(list2.size()).isEqualTo(1);
+        assertThat(list2.get(0)).isEqualTo((byte) 0b00001010);
+
+        List<Byte> list3 = DataElementHeader.convertTypeMultipleBytes(5242398);
+        assertThat(list3.size()).isEqualTo(4);
+        assertThat(list3.get(0)).isEqualTo((byte) 0b10000010);
+        assertThat(list3.get(1)).isEqualTo((byte) 0b10111111);
+        assertThat(list3.get(2)).isEqualTo((byte) 0b11111100);
+        assertThat(list3.get(3)).isEqualTo((byte) 0b00011110);
+    }
+
+    @Test
+    public void test_getTypeMultipleBytes() {
+        byte[] inputBytes = new byte[]{(byte) 0b11011000, (byte) 0b10000000, (byte) 0b00001001};
+        // 0b101100000000000001001
+        assertThat(DataElementHeader.getTypeMultipleBytes(inputBytes)).isEqualTo(1441801);
+
+        byte[] inputBytes2 = new byte[]{(byte) 0b00010010};
+        assertThat(DataElementHeader.getTypeMultipleBytes(inputBytes2)).isEqualTo(18);
+
+        byte[] inputBytes3 = new byte[]{(byte) 0b10000001, (byte) 0b00000000};
+        assertThat(DataElementHeader.getTypeMultipleBytes(inputBytes3)).isEqualTo(128);
+    }
+}