Merge "Update language to comply with Android's inclusive language guidance"

     *

     * <p>IMPORTANT: The use or edit of this method requires a security review.

     *

     * @param masterKey Master key from which to derive sub-keys.

     * @param mainKey Main key from which to derive sub-keys.

     * @param salt A randomly generated 256-bit byte string.

     * @param data Arbitrary information that is bound to the derived key (i.e., used in its

     *     creation).

     * @return Raw derived key bytes = HKDF-SHA256(masterKey, salt, data).

     * @return Raw derived key bytes = HKDF-SHA256(mainKey, salt, data).

     * @throws InvalidKeyException If the salt can not be used as a valid key.

     */

    static byte[] hkdf(byte[] masterKey, byte[] salt, byte[] data) throws InvalidKeyException {

        Objects.requireNonNull(masterKey, "HKDF requires master key to be set.");

    static byte[] hkdf(byte[] mainKey, byte[] salt, byte[] data) throws InvalidKeyException {

        Objects.requireNonNull(mainKey, "HKDF requires main key to be set.");

        Objects.requireNonNull(salt, "HKDF requires a salt.");

        Objects.requireNonNull(data, "No data provided to HKDF.");

        return hkdfSha256Expand(hkdfSha256Extract(masterKey, salt), data);

        return hkdfSha256Expand(hkdfSha256Extract(mainKey, salt), data);

    }

    private Hkdf() {}