How to save alphanumeric text to file that can't be read in Notepad.

[AEI_JR]

I currently have an application that includes a higher level of access to special users.  In order to prevent the login from being "hacked", the password is hard-coded in the executable.  I'd like to make this dynamic so that my users can change the password at will, but don't want anyone to be able to just open the password file in Notepad or equivalent.  Is there a way to convert and save the alphanumeric text in such a format that a simple text reader could not decipher it?

[TCPlomp]

You should store the MD5 has of the password.

In the code you let the user enter the password, calculate the hash and see if they match.

LabVIEW has build in VIs to get the hash of a string.

It is quite hard to decode a password with unkknown length from it's hash.

Additional I would still hard-code a core password only known by you that you can type in yourself. After which you can generate a new password file.

Ton

[AEI_JR]

Since I am unfamiliar with the term "MD5 hash", I did a function search in LabVIEW.  The only function I came up with was "MD5Checksum File.vi", but I can't think how it applies.  Can you be more specific on how one "calculates the hash"?

[TCPlomp]

I am sorry I thought the native MD5 function supported strings.

The OpenG toolkit has a function MD5 Message digest that support strings:

Ton

[aeastet · Accepted solution]

Use encryption. There is a free application in the fourms for Blow Fish. It is very simple and everything is encrypted.

http://zone.ni.com/devzone/cda/epd/p/id/3473

It is very easy to use.

[AEI_JR]

Thanks to you both.  I decided to go the encryption route - it worked exactly as I need.

[JChec]

Hi,

here's something very simple to use to to stop people just opening up the file and reading it. Change the string to a byte integer and alter the values by a known constant, then when reading the byte, alter the values back and convert to a string . Its obviously not much of an encryption but if anyone opens the file they can't read the password.