Derek Developer
<[EMAIL PROTECTED]> wrote:
> Thank you for your replys, but I am still not sure I understand how a
> Query is executed on (page) encrypted data wihout either indexing the
> data prior to encrption, creating a secondary hash column of the data
> or simply decrypting every page to get at the underlying data?

The data _is_ indexed prior to encryption (assuming you did create an 
index on the appropriate column, of course), then the pages containing 
the index are themselves encrypted when written to the file (and 
decrypted when read back, of course).

Encryption is built into the I/O. Whenever a page-worth of data is read 
from disk, it is decrypted right afterwards. When a page is written, 
it's encrypted right before. The I/O engine doesn't care what kind of 
data is on that page - it's only concerned about shuffling bytes in and 
out of storage. The database engine doesn't care whether the file is 
encrypted or not - it always gets plaintext pages from I/O subsystem.

Igor Tandetnik 



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