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Mailing Lists| Author | Message |
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patelraj030
Posts: 3
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Posted 10:55 Mar 21, 2019 |
hey, can you tell me how to select values for d and r in the following sums?
6. In ElGammal, given the prime p = 137, e1= 3 a) Choose d and calculate e2 b) Choose r (it's up to you to decide the value of r) and encrypt the message "happy"; use 00 to 25 for encoding.
7. ElGamal signature scheme. Let p=881, e1 = 3, d=61. find e2. Choose r (it's up to you to decide the value of r).
Thank you |
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JackStrauss
Posts: 236
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Posted 11:05 Mar 21, 2019 |
Please review Lec 04 Review from CS5780 for more information. Choosing "d" and "r" is part of the El Gamal algorithm. See the images below, and see if you understand them. If not, I can try to help you make sense of the material. You're dealing with Groups. See the Z_p* (Star) in the algorithm?
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JackStrauss
Posts: 236
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Posted 11:17 Mar 21, 2019 |
Here is another example that is a bit more thorough. Please see the values of "p", "e", and "d" and "r". Assume you have already chosen "d" and "r" as part of the solution to the problem. View this example, and then view the requirements for the El Gamal algorithm when choosing "d' and choosing "r'. Everything should come together. You are dealing with the group G = <Z_p* (star), X>, This group deals with primes that have a unique multiplicative inverse. Does this sound familiar? The operation you are dealing with is multiplication "x".
Last edited by JackStrauss at
11:30 Mar 21, 2019.
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patelraj030
Posts: 3
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Posted 11:17 Mar 21, 2019 |
Thank you so much for your help |
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JackStrauss
Posts: 236
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Posted 11:18 Mar 21, 2019 |
Not a problem. |
