【发布时间】:2016-12-17 04:34:21
【问题描述】:
我正在尝试将 passphase 编码到属性文件中,这样我就不必输入 passphase 来建立 SSH 连接。但我面临以下错误:
javax.crypto.BadPaddingException: Given final block not properly padded
at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:966)
at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:824)
at com.sun.crypto.provider.AESCipher.engineDoFinal(AESCipher.java:436)
at javax.crypto.Cipher.doFinal(Cipher.java:2165)
at com.test.ssh.SSH_Public_Private.deCryptPwd(SSH_Public_Private.java:191)
at com.test.ssh.SSH_Public_Private.checkHostName(SSH_Public_Private.java:227)
at com.test.ssh.SSH_Public_Private.checkHostName(SSH_Public_Private.java:223)
at com.test.ssh.SSH_Public_Private.connectToSSH(SSH_Public_Private.java:64)
at com.test.ssh.SSH_Public_Private.main(SSH_Public_Private.java:124)
我的代码如下:
private String checkHostName(String hostUserName) throws IOException, InvalidKeyException, InvalidAlgorithmParameterException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
String deCrypted = null;
FileInputStream is = new FileInputStream(new File("C:\\test\\SSH\\PrivateKey\\keystore.properties"));
Properties properties = new Properties();
properties.load(is);
ssh_Public_Private = new SSH_Public_Private();
boolean isHostNameExist = false;
if (properties.getProperty(hostUserName) == null) {
OutputStream outputStream = new FileOutputStream(
"C:\\test\\SSH\\PrivateKey\\keystore.properties");
String passPhraseStored = new String(enCryptPwd());
properties.setProperty(hostUserName,passPhraseStored );
properties.store(outputStream, null);
outputStream.close();
is.close();
return checkHostName(hostUserName);
}else{
System.out.println(properties.getProperty(hostUserName));
String passPhrase = properties.getProperty(hostUserName);
deCrypted = deCryptPwd(passPhrase); //isHostNameExist = true;
}
return deCrypted;
}
My encryption and decryption piece of code is as follow :
private static String enCryptPwd() throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {
String decrypted = null;
byte[] encrypted = null;
try {
String text = "";
Scanner sc = new Scanner(System.in);
System.out.println("Enter your passphrase : " );
text = sc.next();
String key = "Bar12345Bar12345"; // 128 bit key
//String key = "AesSEcREtkeyABCD";
// Create key and cipher
Key aesKey = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
System.out.println(aesKey.getFormat());
Cipher cipher = Cipher.getInstance("AES");
// encrypt the text
cipher.init(Cipher.ENCRYPT_MODE, aesKey);
encrypted = cipher.doFinal(text.getBytes("UTF-8"));
System.err.println(new String(encrypted));
System.err.println(encrypted.length);
} catch (Exception e) {
e.printStackTrace();
}
return new String(encrypted);
}
private static String deCryptPwd(String encrypted) throws InvalidKeyException, InvalidAlgorithmParameterException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
String originalString = "";
try {
String key = "Bar12345Bar12345"; // 128 bit key
//String key = "AesSEcREtkeyABCD";
// Create key and cipher
Key aesKey = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
Cipher cipher = Cipher.getInstance("AES");
// decrypt the text
cipher.init(Cipher.DECRYPT_MODE, aesKey);
byte[] encryptBytes = new byte[encrypted.length()];
encryptBytes = encrypted.getBytes();
byte[] decrypted = cipher.doFinal(encryptBytes);
originalString = new String(decrypted, "UTF-8");
System.out.println(originalString);
System.err.println(decrypted);
} catch (Exception e) {
e.printStackTrace();
}
return originalString;
}
我一直在尝试阅读并尝试了许多其他方法,包括不包含填充算法。我的代码将输出写入属性文件:
abced=Y\u201Eh\uFFFD\u00EC-:\u00F9\u00F8mC\u0160\u0002\u00F3#\u00DE
我的控制台输出是:
输入您的密码: abc!@#
加密后>> Y„h?ì-:ùømCŠó#Þ
16
从属性文件中读取 >> Y„h?ì-:ùømCŠó#Þ
【问题讨论】:
-
您的编码已关闭。如果您计算“加密后”显示的字符数,您会发现只有 15 个字符,而不是预期的 16 个。
-
请注意,加密是基于字节而不是基于字符的。加密数据几乎总是不能作为文本打印,它显示为一个 8 位随机字节数组。为了显示问题,对加密数据进行十六进制编码。
-
如果您对“passphase”进行加密,您将如何保护该加密密钥?
-
一般建议:始终使用完全限定的密码字符串。
Cipher.getInstance("AES");可能会产生不同的密码,具体取决于默认的安全提供程序。它最有可能导致"AES/ECB/PKCS5Padding",但并非必须如此。如果它发生变化,您将失去不同 JVM 之间的兼容性。 -
切勿使用ECB mode。它是确定性的,因此在语义上不安全。您至少应该使用像CBC 或CTR 这样的随机模式。最好对您的密文进行身份验证,以免像padding oracle attack 这样的攻击是不可能的。这可以通过 GCM 或 EAX 等经过身份验证的模式或encrypt-then-MAC 方案来完成。
标签: java encryption aes