Re: [mdb-dev] [PATCH] implement handling of encrypted databases

[Brian B. <ca...@ai...>]

David,

Send me your sourceforge account name and I'll give you check in rights.  
Sorry I dont have time to merge the patches but I'm in the process of 
moving, ehh!

Brian

On Thu, 15 May 2003 da...@co... wrote:

> 
> Hi Brian,
> 
> This patch (on top of all of my other patches, 00 thru 18, which I can
> resend to you if you want) implements handling of encrypted databases.
> 
> The technique for encrypting databases by access appears to be as follows:
> 
> - each data page except for page 0 (2k pages for jet3, 4k for jet4) is
> encrypted separately using the RC4 algorithm and with a different key
> 
> - the key can be obtained by XORing together the following:
> 
>   - the database key, found at offset 0x3e from the start of the file
>   - the 'unencrypted' key, found at offset 0x3e of any unencrypted 
>     database (this appears to be 0x4ebc8afb when taking endianness 
>     into account)
>   - the page number
> 
> The existing code already extracted the database key, and XORed it with 
> the number 0xe15e01b9.  I don't know where this number came from, but I 
> can imagine there may be more than one 'unencrypted' key.  I added the rc4 
> routines to src/libmdb/file.c.  They could be replaced easily with calls 
> to openssl (the interface I used is almost identical to the openssl 
> routines).
> 
> This works for the one encrypted database I needed to access. YMMV.
> 
> David
> 
> P.S. to enable other people to find this post with a search engine I 
> include the following keywords.  I had a really hard time finding out 
> information about this topic.
> 
> msaccess microsoft ac97 access97 mdb dbEncrypt CompactDatabase
> 
> 
>