
public class encode {
    private static byte[] b = {23, 22, 26, 26, 25, 25, 25, 26, 27, 28, 30, 30, 29, 30, 32, 32};

    public static boolean check(String str) {
        byte[] input = str.getBytes();
        byte[] temp = new byte[16];
        for (int i = 0; i < 16; i++) {
            temp[i] = (byte) ((input[i] + b[i]) % 61);
        }
        for (int i2 = 0; i2 < 16; i2++) {
            temp[i2] = (byte) ((temp[i2] * 2) - i2);
        }
        String key = new String(temp);
        return key.equals(str);
    }
}

整理得：
（(input[i] + b[i]) % 61) * 2 -i = input[i]
设：input[i] = x 

 b[i]%61 * 2 - i = x - x % 61 * 2


