Question

我尝试解码时遇到错误。这是解码器：

public class Encrypter {

    Cipher ecipher;
    Cipher dcipher;

    SecretKeySpec key = new SecretKeySpec("missyou1".getBytes(), "DES");

    public DesEncrypter() throws Exception {
        ecipher = Cipher.getInstance("DES");
        dcipher = Cipher.getInstance("DES");
        ecipher.init(Cipher.ENCRYPT_MODE, key);
        dcipher.init(Cipher.DECRYPT_MODE, key);
    }

    public String encrypt(String str) throws Exception {
        byte[] utf8 = str.getBytes("UTF8");
        byte[] enc = ecipher.doFinal(utf8);
        return new sun.misc.BASE64Encoder().encode(enc);
    }

    public String decrypt(String str) throws Exception {
        byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);

        byte[] asd = new byte[(dec.length/8+1)*8];
        for(int i = 0; i < dec.length; i++){
            asd[i] = dec[i];
        }
        byte[] utf8 = dcipher.doFinal(asd);

        return new String(utf8, "UTF8");
    }
}

这是我收到错误的代码：

private static void appenda(Encrypter encrypt) {
        if (Files.exists(Paths.get(filePath), new LinkOption[] { LinkOption.NOFOLLOW_LINKS })) {
            Stream<String> stringStream = null;
            try {
                stringStream = Files.lines(Paths.get(filePath), StandardCharsets.UTF_8);
            } catch (IOException e) {
                LOGGER.error("Failed ", e);
            }

            if (stringStream.toString() != null) {
                stringStream.forEach(s -> {
                    try {
                        System.out.println(encrypt.decrypt(s));
                        endpoint.delete(0, endpoint.length());
                        endpoint.append(encrypt.decrypt(s));
                    } catch (Exception e) {
                        LOGGER.error("Failed to decrypt", e);
                    }
                });
            }
        }
    }

第endpoint.append(encrypter.decrypt(s));行

知道为什么吗？

Answer 1

它不起作用，因为你不必要地将数据复制到一个大小不正确的数组中。

只需删除数组副本并直接解密字节。

public String decrypt(String str) throws Exception {
    byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);
    byte[] utf8 = dcipher.doFinal(dec);
    return new String(utf8, "UTF8");
}

javax.crypto.BadPaddingException：给定最终块没有正确填充DES

1 个答案: