Re: PGP scripting...

From: Andre Mariën (andre.marien@ubizen.com)
Date: 01/09/03

  • Next message: lsi: "PGP scripting (reprise)" 
    Date: Thu, 09 Jan 2003 10:47:55 +0100
From: Andre Mariën <andre.marien@ubizen.com>

    Tom Arseneault wrote:

    > As for the usage of the key in encryption and decryption, public key
    > encryption is very compute intensive so while you could do bulk encryption
    > with it whould be very slow.. The usual way things are done is that a
    > symmetrical encryption will be used to encrypt a document (DES, 3DES,
    > BLOWFISH, etc..., very fast) with a randomly generated key and that key is
    > then encrypted with the public key of the person you sending the document
    > to. Since only he, through the use of his private key, can decrypt the
    > symmetrical key only he can decrypt the document.

    Please do not use public key encryption for bulk data, even if
    you accept the long times. It is a bad idea. If there are n
    possible messgaes, it only takes at most n trials to decrypt
    the message, no matter your key size (if the encrypting key is known;
    typically it is the public key and it is known).
    This problem is justification in itself to have a two stage system
    for encryption of bulk data.
    (there is someone at counterpane that can explain it in more detail ;-)

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