*/
    public char[] decryptFromString(String encryptedString) throws GeneralSecurityException {
        if (encryptedString == null) {
            return null;
        }
        byte[] encrypted = Base64.getDecoder().decode(encryptedString);
        return decryptCredentials(encrypted);
    }

    /**
     * Get the salt used for key derivation
     *
     * @return salt bytes
     */

        assertEquals("NTLM ", headerValue.substring(0, 5), "Header should start with 'NTLM '");

        // Decode the returned Type 2 message and check its signature and type
        byte[] type2Bytes = Base64.getDecoder().decode(headerValue.substring(5));
        assertEquals('N', (char) type2Bytes[0]);
        assertEquals('T', (char) type2Bytes[1]);
        assertEquals('L', (char) type2Bytes[2]);

        assertNotNull(id);
        assertEquals(Base64.getEncoder().encodeToString(text.getBytes(CoreLibConstants.CHARSET_UTF_8)), id);

        // Test empty text
        String emptyText = "";
        String emptyId = SuggestUtil.createSuggestTextId(emptyText);
        assertNotNull(emptyId);
        assertEquals(Base64.getEncoder().encodeToString(emptyText.getBytes(CoreLibConstants.CHARSET_UTF_8)), emptyId);

    /** Settings ID. */
    protected final String settingsId;
    /** Suggest settings. */
    protected final SuggestSettings settings;

    private static final Base64.Encoder encoder = Base64.getEncoder();

    /**
     * Constructor.
     * @param settings Suggest settings
     * @param client OpenSearch client
     * @param settingsIndexName Settings index name
     * @param settingsId Settings ID

 */
public final class SuggestUtil {
    private static final int MAX_QUERY_TERM_NUM = 5;
    private static final int MAX_QUERY_TERM_LENGTH = 48;

    private static final Base64.Encoder encoder = Base64.getEncoder();

    private static final int ID_MAX_LENGTH = 445;

    /**
     * Private constructor to prevent instantiation.
     */
    private SuggestUtil() {
    }

    /**