I am making QR codes that cell phone users scan in order to make use of an application. Part of the information is a token that needs to be passed on to the server, but I'd rather not allow a person examining the QR code to be able to see that plain bit of information. I'd like to scramble up the token so that the result:
1) takes up the same (near, or less) number of characters as the original token.
2) They key can be derived from the input, and vise versa. 3) The result is alphanumeric. 4) When one character changes in the source, many characters are likely to change in the result. So if my token is: mytoken2011 The result might be something like: xm23ffz4uuw Then mytoken2012 might yield something very different: d8ru3jdhvhd I was thinking of just stringing up all letters and numbers into a 'wheel' and doing an 18 char rotation on the chars in the token, but that fails #4. The secret is not like the key to Fort Knox. We would rather not have the plain token out there, as it's internal business information, but we don't have to protect the information at all costs. Just making it really inconvenient to extract is fine. Thanks, Tobiah -- http://mail.python.org/mailman/listinfo/python-list