'scramble' string

[Steve]

Hi,

I am trying to do a very simple "encryption " of a text string in java
script. For instance, if the user enters : steve, I want to just
convert each character to its ASCII value and add 5 to each character,
then convert back to a string giving: "xyj{j" for this example.

is there a simple way to do this? any suggestions on functions I can
use would be greatful!

Thanks,
Steve

[Dag Sunde]

Re: 'scramble' string

"Steve" <steve551979@ho tmail.com> wrote in message
news:e3805b94.0 405102049.4f4fd 158@posting.goo gle.com...[color=blue]
> Hi,
>
> I am trying to do a very simple "encryption " of a text string in java
> script. For instance, if the user enters : steve, I want to just
> convert each character to its ASCII value and add 5 to each character,
> then convert back to a string giving: "xyj{j" for this example.
>
> is there a simple way to do this? any suggestions on functions I can
> use would be greatful!
>[/color]

The most well-known of those are probably the "ROT-13" algorithm, where
you have the 26 letters in a "Ring" buffer. For each letter in your string,
you add 13, and use the letter in that position instead.

Now the magic: when you add 13 the second time, you will be back to your
original letter.

Below is a Java implementation of a variation of rot13, which I've called
Rot39. (Excactly the same as rot13, but uses a larger "ring" of characters).

It should be relatively simple to implement this in JavaScript...

public class Scramble
{
private final static int UPPER_LIMIT = 125;
private final static int LOWER_LIMIT = 48;
private final static int CHARMAP = 39;

public Scramble()
{
}

/**
* rot39 is a variation of the ROT13 algorithm,
* that also scrambles numbers and, most important in this
* case; xml-tags ("<", ">" & "/")
* @param - data, String to (de)scrambled
* @return - The string in "data" in (de)scrambled form.
*/
public String rot39(String data)
{
try
{
byte[] buffer = data.getBytes(" ISO-8859-1");

for(int iData = 0; iData < buffer.length; iData++)
{
int iCode = buffer[iData];
if((iCode >= LOWER_LIMIT) && (iCode <= UPPER_LIMIT ))
{
iCode+= CHARMAP;
if(iCode > UPPER_LIMIT)
{
iCode = iCode - UPPER_LIMIT + LOWER_LIMIT - 1;
}
buffer[iData] = (byte)iCode;
}
}
return new String(buffer, "ISO-8859-1");

}
catch( java.io.Unsuppo rtedEncodingExc eption e)
{
System.out.prin tln("Unicode/ISO FuckUp!");
System.exit(-1);
return "";
}
}
}

--
Dag
58°26'15.9" N 008°46'45.5" E

[Gernot Frisch]

Re: 'scramble' string


"Steve" <steve551979@ho tmail.com> schrieb im Newsbeitrag
news:e3805b94.0 405102049.4f4fd 158@posting.goo gle.com...[color=blue]
> Hi,
>
> I am trying to do a very simple "encryption " of a text string in[/color]
java[color=blue]
> script. For instance, if the user enters : steve, I want to just
> convert each character to its ASCII value and add 5 to each[/color]
character,[color=blue]
> then convert back to a string giving: "xyj{j" for this example.
>
> is there a simple way to do this? any suggestions on functions I[/color]
can[color=blue]
> use would be greatful!
>
> Thanks,
> Steve[/color]

Make 2 arrays. One with all allowed characters and another with the
characters in a different order.
e.g.
"ABCDEabcde " vs "AbCdEaBcDe "
Now this is your dictionary. When scambling seek for character in A
and use the character at this position in B. Unscrable by swapping
lists.

BTW: Doing this in JavaScript is a bit ridicoulosly, since the source
code is available to everyone...

HTH,
Gernot

[Lasse Reichstein Nielsen]

Re: 'scramble' string

steve551979@hot mail.com (Steve) writes:
[color=blue]
> I am trying to do a very simple "encryption " of a text string in java
> script. For instance, if the user enters : steve, I want to just
> convert each character to its ASCII value and add 5 to each character,
> then convert back to a string giving: "xyj{j" for this example.
>
> is there a simple way to do this? any suggestions on functions I can
> use would be greatful![/color]

The two functions you need are
charCodeAt (on string objects)
and
fromCharCode (on String)

Example
---
function encodeString(st ring) {
var chars = [];
for(var i=0;i<string.le ngth;i++) {
chars[i] = String.fromChar Code(string.cha rCodeAt(i)+5);
}
return chars.join("");
}
---
(Collecting a lot of small strings in an array and joining them
once is more efficient than concatenating strings each round of
the loop).

/L
--
Lasse Reichstein Nielsen - lrn@hotpop.com
DHTML Death Colors: <URL:http://www.infimum.dk/HTML/rasterTriangleD OM.html>
'Faith without judgement merely degrades the spirit divine.'

[Shawn Milo]

Re: 'scramble' string

steve551979@hot mail.com (Steve) wrote in message news:<e3805b94. 0405102049.4f4f d158@posting.go ogle.com>...[color=blue]
> Hi,
>
> I am trying to do a very simple "encryption " of a text string in java
> script. For instance, if the user enters : steve, I want to just
> convert each character to its ASCII value and add 5 to each character,
> then convert back to a string giving: "xyj{j" for this example.
>
> is there a simple way to do this? any suggestions on functions I can
> use would be greatful!
>
> Thanks,
> Steve[/color]

Depending upon what you're trying to do, you can always use md5 encrytion.
It's one-way only, so if you're planning on converting the string back
later, then this won't work.

Shawn