On Tue, 23 Aug 2011 06:27:39 -0700, Tobiah wrote: > 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:
Can you not just encrypt the data with a fixed secret key? A fixed key satisfies #2. #3 can almost be satisfied by using base-64, or can be entirely satisfied by using base-36 or base-62 (these are less efficient, but that doesn't matter for small amounts of data). #1 can be satisfied by compressing the text beforehand; this should almost exactly compensate for the expansion caused by #3. Any block cipher in CBC mode will satisfy #4 (it will even be satisfied in ECB mode if the compressed token is smaller than the cipher block size). -- http://mail.python.org/mailman/listinfo/python-list
