Wednesday, May 07, 2008
RC4 encryption for classic ASP stops working
This was an interesting gotcha which I'd like to blame on Visual Studio 2008, but it is undeserved.
Microsoft dropped support for Intellisense and color-coding for classic ASP in Visual Studio 2008, but I still use it to maintain some old sites.
Well, after some minor changes to an old site, suddenly, the RC4 encryption code, by Mike Shaffer, that I was using didn't work any more. The answer really surprised me.
To make a LONG story short, I opened the site in VS08 and created a new include file for a page I was modifying. I included the file into the primary page and that caused the RC4 code to stop producing the correct output.
Visual Studio 2008 created the new include file using UTF-8 encoding. Well, for some reason that broke the RC4 encryption code. I guess it's because each character would be 2 bytes instead of 1? I thought that was just Unicode and classic ASP won't even process a Unicode file (UNICODE ASP files are not supported). I don't know.
My resolution was to make sure the classic ASP page and all its includes were saved as ANSI text. Here Notepad++ (Menu > Format > Encode in ANSI) came in very handy again.
Maybe someday I will understand The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character. Scott Hanselman also has an interesting post on the CodePage versus the CharSet in classic ASP.
Microsoft dropped support for Intellisense and color-coding for classic ASP in Visual Studio 2008, but I still use it to maintain some old sites.
Well, after some minor changes to an old site, suddenly, the RC4 encryption code, by Mike Shaffer, that I was using didn't work any more. The answer really surprised me.
To make a LONG story short, I opened the site in VS08 and created a new include file for a page I was modifying. I included the file into the primary page and that caused the RC4 code to stop producing the correct output.
Visual Studio 2008 created the new include file using UTF-8 encoding. Well, for some reason that broke the RC4 encryption code. I guess it's because each character would be 2 bytes instead of 1? I thought that was just Unicode and classic ASP won't even process a Unicode file (UNICODE ASP files are not supported). I don't know.
My resolution was to make sure the classic ASP page and all its includes were saved as ANSI text. Here Notepad++ (Menu > Format > Encode in ANSI) came in very handy again.
Maybe someday I will understand The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character. Scott Hanselman also has an interesting post on the CodePage versus the CharSet in classic ASP.
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