Decoding Old StringEncrypt Strings

[swoop]

I have some old AutoIt code that saves the encrypted string from StringEncrypt function into the Windows registry.

But when I go to try to decrypt it using the new _Crypt_DecryptData ( $input, $base_key, $CALG_RC4 ), I cannot get the old data back out.

I've tried:

BinaryToString (_Crypt_DecryptData ( $input, $base_key, $CALG_RC4 ) )

_Crypt_DecryptData ( StringToBinary ($input), $base_key, $CALG_RC4 ) 

and different combinations, but I cannot get the original text back out.

Has anyone encountered this issue? This breaks my program when I have to use _Crypt_DecryptData instead of the old StringEncrypt. It cannot fetch the data previously stored in the Windows Registry.

[rcmaehl]

Couple of questions?

• Have you checked the data types being handled?

Try $input = Execute($input) before passing it to _Crypt_DecryptData

• Did you check data provided by RegRead?

Registry values can be a little tricky sometimes

• Can you provide the exact code that you're using?

In case the above doesn't work.

Edited September 3, 2016 by rcmaehl

[jchd]

_StringEncrypt and friends were removed due to terrible bugs, so it isn't recommended for new design of course.

The _Crypt* function rely on much stronger feet but aren't anyway compatible with this "encryption". You should download an old version of AutoIt (prior to 3.3.10.0) to extract the _StringDecrypt function used at that time.

[swoop]

I did go back to an older version as suggested by jchd to at least fetch the data created by the old encryption.

However, this still does present a problem of my application, which I would like to compile with the latest AutoIT, but still needs to retrieve for previous users who encrypted data using the older application. I guess the only other way, if I cannot use StringEncrypt or some function that can decrypt the legacy encryption, is to write some upgrade application that will take the old data under 3.3.10.0 and save it temporarily to a text file and then encrypt it again using the latest _Crypt functions. Though this is not a very secure way to transfer the data to the new encryption format.

[jchd]

Copy the old String.au3 UDF and extract the relevant function(s) then include it(them) in your application and compile using your up-to-date installation.

[swoop]

Thanks jchd. That was helpful. Made a big difference.