Encryption question

[Steve Kallal]

I need to find a form of encryption that always encrypts a given plain text
string to the exact same encrypted string every time. I want to use a form of
output caching in my ASP.NET application that will use a cached version of a
web page if the query string parameters are exact each time. If the encrypted
query string varies each time, even with the same plain text string, the
cache likely will not work.

Every encryption algorithm I have tried so far using the System.Security
namespace, produces a different encrypted string each time I try it.

Thanks in advance!

Steve Kallal

 

[Alek Davis]

Steve,

Every encryption algorithm when used with the same key (and initialization
vector, IV, if applicable) will produce the same ciphertext value from the
same plaintext value. Are you saying that you cannot find a sample code that
would allow you to encrypt the same value (with the same key and IV) and
generate the consistent result? If this is the case, you may not be doing it
correctly. Please forget about your application for a moment and just try to
solve the problem with a simple text string. There are many examples online
explaining ho to do this. If this is not the case, and you cannot achieve
consistent results for your particular application (not really sure what you
are doing regarding caching of the ASP.NET pages), then you need to focus on
the inputs. Make sure that plaintext converted to byte arrays, and key
characteristics (key bytes, or password, IV, salt, password iterations,
hashing algorithm) are the same.

Alek

 

[Alek Davis]

Try http://www.obviex.com/samples/encryption.aspx or
http://dotnet.org.za/deon/articles/2998.aspx (if you do a Google search, you
will find many more; I was too lazy to go through more than the first dozen
of the returned result).

Alek