Encryption result only in alpha numeric

Question

I want to encrypt a String to an cipher which consists only of alphabets (a-z/A-Z) and numbers(0-9). I doesn't want it to have any other characters (=, &, !.. etc).

Is there any way to achieve it? If so, can please someone help me out. A java code will be preferred without any external libraries.

Note:

I have already tried base64 encoding but it does't work as it uses '=' as padding character.
This generated cipher will be used in web urls to pass values.
The cipher should also be decoded back to original String.

I'm trying to pass some values in the url. Eg: `http://website.com?value=cipher&value=cipher` where the value must be alphanumeric. If the cipher contains any other characters like '=' or '&' it will break the link structure. That's why I'm concerned. @JimGarrison — Prasenjeet Paul, May 27 '18 at 18:22
You can simply use any cipher and then encode is using e.g. URLEncoder — Michal, May 27 '18 at 18:27
for two way encryption you can take a look here https://stackoverflow.com/questions/15554296/simple-java-aes-encrypt-decrypt-example. What you get is encrypted Base64 encoded string and then encode it with URLEncoder.encode(string, "UTF-8"). after you can safely use it as url parameter — Michal, May 27 '18 at 18:56
For a different use, I am using Base64 encoding and then replace '+', '/', '=' with '-', '_', and '.' — Juan, May 27 '18 at 19:19
Thanks for all your inputs. I found the solution on my own. I used Base32 encoding instead. [Post link](https://stackoverflow.com/questions/4375830/java-based-encrypter-that-produces-only-alphanumeric-characters?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa) This post was very helpful. — Prasenjeet Paul, May 28 '18 at 12:46

score -1 · Answer 1 · answered May 27 '18 at 18:25

-1

Assuming one way hash is enough for you, you can implement something like this

public String hashToHexString(String whatever) throws NoSuchAlgorithmException{

        byte[] digest = MessageDigest.getInstance("your one way hash alghoritm")
                .digest(whatever.getBytes());
        return DatatypeConverter.printHexBinary(digest);

}

answered May 27 '18 at 18:25

Michal

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Thanks for your efforts, but no. I actually want a two way encryption. I want to encrypt as well as decrypt. – Prasenjeet Paul May 27 '18 at 18:30

Encryption result only in alpha numeric

1 Answers1