In message <[EMAIL PROTECTED]> on Thu, 23 Dec 2004 13:18:13 -0500, david zhang 
<[EMAIL PROTECTED]> said:

davidzhanginottawa> I am wondering why the decryption routine knows if
davidzhanginottawa> a decryption is correct or not without comparing
davidzhanginottawa> with the original plaintext file? Is there
davidzhanginottawa> something inside the encrypted file "hello.enc"
davidzhanginottawa> contains some data which do the magic?

It knows because if decryption has failed, the padding pattern at the
end will be faulty.  Read PKCS#5 to see what padding is used for this
kind of operation.

Cheers,
Richard

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Richard Levitte                         [EMAIL PROTECTED]
                                        http://richard.levitte.org/

"When I became a man I put away childish things, including
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                                                -- C.S. Lewis
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