java - make string unreadable [closed]

问题

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.

Closed 6 years ago.

I need an as short and fast as possible code to change a String to something unreadable (for humans that is), and also to make it readable again. It all needs to happen in java.

Something like this:

encrypt("test");

Would result in something like this:

ôT¿ÄÜTV CÁˆ“5="ËÂÀœššbÀß{¡ä³

and

decrypt("ôT¿ÄÜTV CÁˆ“5 1="ËÂÀœššbÀß{¡ä³");

would than again result into the original

test

What direction should I go, are there any classes that can do this for me? I don't mean something like Base68Encryption or whatever it might be called, I mean a true unreadable text that I can safely send over the internet.

回答1:

See encryption and decryption of data algorithgms with example code http://www.code2learn.com/2011/06/encryption-and-decryption-of-data-using.html. Encryption / decription is embedded in JRE and is not difficult to use.

回答2:

Here is a very short example of using true encryption. It's 128 bit AES, which is farily secure - certainly not readable by any stretch of the imagination.

It generates a random key, so it would be different on each run. You would need to share they key between the two programs exchanging data somehow.

private static final String ENCRYPTION_ALGORITHM = "AES/ECB/PKCS5Padding";
private static final SecureRandom RANDOM = new SecureRandom();

public static void main(String[] args) throws UnsupportedEncodingException, GeneralSecurityException {
    final KeyGenerator keyGen = KeyGenerator.getInstance(ENCRYPTION_ALGORITHM.substring(0, ENCRYPTION_ALGORITHM.indexOf('/')));
    keyGen.init(128, RANDOM);
    final SecretKey key = keyGen.generateKey();
    final String s = "My topsecret string";
    System.out.println(s);
    final Cipher encryption = getCipher(key, Cipher.ENCRYPT_MODE);
    final String enc = DatatypeConverter.printBase64Binary(encryption.doFinal(s.getBytes("UTF-8")));
    System.out.println(enc);
    final Cipher decryption = getCipher(key, Cipher.DECRYPT_MODE);
    final String dec = new String(decryption.doFinal(DatatypeConverter.parseBase64Binary(enc)), "UTF-8");
    System.out.println(dec);
}

private static Cipher getCipher(final Key key, final int mode) throws GeneralSecurityException {
    final Cipher cipher = Cipher.getInstance(ENCRYPTION_ALGORITHM);
    cipher.init(mode, key, RANDOM);
    return cipher;
}

Output:

My topsecret string
ip4La5KUBJGTTYenoE920V5w0VBHwALv4fp3qyLTY9o=
My topsecret string

回答3:

What direction should I go, are there any classes that can do this for me? I don't mean something like Base68Encryption or whatever it might be called, I mean a true unreadable text that I can safely send over the internet.

There are two ways to address this:

• You could pick one of the existing high quality encryption systems that is implemented as standard in a typical JVM. Then:

  1. Encode the string as bytes; e.g. using UTF-8.

  2. Encrypt the bytes using an agreed encryption system, and a previously agreed key.

  3. Encode the bytes using base_64 or equivalent.

  and at the other end:

  1. Decode the base_64

  2. Decrypt the bytes with the same system and key.

  3. Decode the UTF-8 to get a String.

• Use SSL/TLS to secure the TCP/IP connection, and send the String over the connection as-is.

Neither of these options is particularly fast. But don't be tempted to try and invent your own faster encryption system. The chances are that a "home brewed" encryption system it will be a lot easier to break than you realize.

来源：https://stackoverflow.com/questions/16238634/java-make-string-unreadable