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diff --git a/src/java/com/android/internal/net/crypto/KeyGenerationUtils.java b/src/java/com/android/internal/net/crypto/KeyGenerationUtils.java
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+++ b/src/java/com/android/internal/net/crypto/KeyGenerationUtils.java
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+/*
+ * Copyright (C) 2019 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.internal.net.crypto;
+
+import java.nio.ByteBuffer;
+
+/**
+ * KeyGenerationUtils is a util class that contains utils for key generation needed by IKEv2 and
+ * EAP.
+ */
+public class KeyGenerationUtils {
+    /**
+     * Returns the derived pseudorandom number with the specified length by iteratively applying a
+     * PRF.
+     *
+     * <p>prf+(K, S) outputs a pseudorandom stream by using the PRF iteratively. In this way it can
+     * generate long enough keying material containing all the keys.
+     *
+     * @see <a href="https://tools.ietf.org/html/rfc7296#section-2.13">RFC 7296 Internet Key
+     *     Exchange Protocol Version 2 (IKEv2) 2.13. Generating Keying Material </a>
+     * @param byteSigner the PRF used to sign the given data using the given key.
+     * @param keyBytes the key to sign data.
+     * @param dataToSign the data to be signed.
+     * @param keyMaterialLen the length of keying materials to be generated.
+     * @return the byte array of keying materials
+     */
+    public static byte[] prfPlus(
+            ByteSigner byteSigner, byte[] keyBytes, byte[] dataToSign, int keyMaterialLen) {
+        ByteBuffer keyMatBuffer = ByteBuffer.allocate(keyMaterialLen);
+
+        byte[] previousMac = new byte[0];
+        final int padLen = 1;
+        byte padValue = 1;
+
+        while (keyMatBuffer.remaining() > 0) {
+            ByteBuffer dataToSignBuffer =
+                    ByteBuffer.allocate(previousMac.length + dataToSign.length + padLen);
+            dataToSignBuffer.put(previousMac).put(dataToSign).put(padValue);
+
+            previousMac = byteSigner.signBytes(keyBytes, dataToSignBuffer.array());
+
+            keyMatBuffer.put(
+                    previousMac, 0, Math.min(previousMac.length, keyMatBuffer.remaining()));
+
+            padValue++;
+        }
+
+        return keyMatBuffer.array();
+    }
+
+    /**
+     * ByteSigner is an interface to be used for implementing the byte-signing for generating keys
+     * using {@link KeyGenerationUtils#prfPlus(ByteSigner, byte[], byte[], int)}.
+     */
+    public interface ByteSigner {
+        /**
+         * Signs the given data using the key given.
+         *
+         * <p>Caller is responsible for providing a valid key according to their use cases.
+         *
+         * @param keyBytes the key to sign data.
+         * @param dataToSign the data to be signed.
+         * @return the signed value.
+         */
+        byte[] signBytes(byte[] keyBytes, byte[] dataToSign);
+    }
+}