java - 在java中解密在android应用程序中加密的字符串

Question

我正在使用这个类来加密 android 应用程序中的字符串

public class Encryption {
     public static String encrypt(String seed, String cleartext) throws Exception {
            byte[] rawKey = getRawKey(seed.getBytes());
            byte[] result = encrypt(rawKey, cleartext.getBytes());
            return toHex(result);
        }

        public static String decrypt(String seed, String encrypted) throws Exception {
            byte[] rawKey = getRawKey(seed.getBytes());
            byte[] enc = toByte(encrypted);
            byte[] result = decrypt(rawKey, enc);
            return new String(result);
        }

        private static byte[] getRawKey(byte[] seed) throws Exception {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
            sr.setSeed(seed);
            kgen.init(128, sr); // 192 and 256 bits may not be available
            SecretKey skey = kgen.generateKey();
            byte[] raw = skey.getEncoded();
            return raw;
        }


        private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
            Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
            byte[] encrypted = cipher.doFinal(clear);
            return encrypted;
        }

        private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
            Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.DECRYPT_MODE, skeySpec);
            byte[] decrypted = cipher.doFinal(encrypted);
            return decrypted;
        }

        public static String toHex(String txt) {
            return toHex(txt.getBytes());
        }
        public static String fromHex(String hex) {
            return new String(toByte(hex));
        }

        public static byte[] toByte(String hexString) {
            int len = hexString.length()/2;
            byte[] result = new byte[len];
            for (int i = 0; i < len; i++)
                result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
            return result;
        }

        public static String toHex(byte[] buf) {
            if (buf == null)
                return "";
            StringBuffer result = new StringBuffer(2*buf.length);
            for (int i = 0; i < buf.length; i++) {
                appendHex(result, buf[i]);
            }
            return result.toString();
        }
        private final static String HEX = "0123456789ABCDEF";
        private static void appendHex(StringBuffer sb, byte b) {
            sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));
        }
}

我正在像这样使用上面的类 -

Encryption.encrypt("password", "some text to be encrypted");

他们在加密字符串方面没有问题，但是当我尝试在外部 java 程序(不在 android 应用),

Encryption.decrypt("password","D4036388D459C4009812FB3F1AE4BB36E4419C97775D");

我得到这个异常-

javax.crypto.BadPaddingException: Given final block not properly padded
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)
    at Encryption.decrypt(Encryption.java:59)
    at Encryption.decrypt(Encryption.java:32)
    at Encryption.main(Encryption.java:96)

我想，这是因为我在不同的平台上使用相同的代码，

但我不知道这不起作用的正确原因？和他们有什么办法可以用 Java 解密字符串吗？

Answer 1

@SteveP 可能是对的。

我看到的另一个问题是 byte[] getBytes("UTF-8") (二进制数据)到 String new String(bytes, "UTF-8")(文本)转换。在 Android 上，默认编码是 UTF-8，在 Windows 上很可能是其他编码。