Re: ElGamal Encryption

James A. Donald (jamesd@echeque.com)
Sun, 14 Feb 1999 15:44:10 -0800

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    --
At 02:28 PM 2/13/99 +0000, Walied.Othman@student.kuleuven.ac.be wrote:
>To encrypt a message using ElGamal a user needs to choose a
>random number for an exponent, suppose the message is
>longer than the modulus, we would have to divide the
>message into blocks smaller than the modulus

No we would not:

Instead we encrypt a random number, and use that random
number as the key for encryption using a shared secret.
Typically the random number is 128 bits long, and is used as
the key for RC4 (arc4) encryption.

    --digsig
         James A. Donald
     6YeGpsZR+nOTh/cGwvITnSR3TdzclVpR0+pr3YYQdkG
     L0ie05tOvjCprAXQCaAaR9J5LV+1/+jsmiKYzHdt
     4l3Tbp4VVL1TipoNIvfuiGCRmIEH76/3Chl2VitVu
-----------------------------------------------------
We have the right to defend ourselves and our property, because
of the kind of animals that we are. True law derives from this
right, not from the arbitrary power of the omnipotent state.

http://www.jim.com/jamesd/      James A. Donald

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