Re: Simple URL encoding technique?
David Segall wrote:
Arne Vajh?j <arne@vajhoej.dk> wrote:
David Segall wrote:
My JSP application asks users to visit a web site with a URL of the
form <www.example.com?column=100&row 0>. This makes it far too easy
for an intruder to derive a different column and row that may yield a
real location to which they should not have access. Is there an
existing method that can "obfuscate" (and de-obfuscate) the column and
row number. It is easy to concatenate the row and column numbers if
that is a desirable first step. I don't need a high level of security
because the there is nothing of real value at the destination; I just
want to foil a casual vandal.
1) you can left zero pad to 4 digits and concatanate 100 and 200
to "01000200", which you can then 3DES or AES encrypt with a
secret key and hexify - and dehexify and decrypt again
Thanks Arne. Hexify(column * 16384 + row) will do nicely. I don't
think I need the encryption. Is there a "standard" routine to convert
an integer to a hexadecimal string and back?
int iv = 123;
String sv2;
sv2 = Integer.toHexString(iv);
and
String sv = "7b";
int iv2;
iv2 = Integer.parseInt(sv, 16);
are two possibilities.
2) but you should really implement security instead of obscurity -
you should validate a users access to data when it is submitted
The application is comparable to "click on this link to confirm your
subscription". I don't want to inconvenience the user by requiring
extra information but I also want to minimise the possibility that one
user can derive valid parameters that belong to someone else.
Your app => your choice.
Arne
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