CODEWITHSUNDEEP
elliptic-curveelgamal
MHS
MHS

Reputation: 55

How represent message for Elgamal EC?

I am working on my project that uses elgamal elliptic curve. I know when the elgamal ec encrypt by following steps

  1. Represent the message m as a point M in E(Fp).
  2. Select k ∈R [1,n−1].
  3. Compute C1 = kP.
  4. Compute C2 = M +kQ.
  5. Return(C1,C2).
    Where Q is the intended recipient’s public key, P is base point. My qusetion at number one. how represent m as a point. Is point represent one character or represent group of characters.

Upvotes: 0

Views: 831

Answers (1)

Chiara Hsieh
Chiara Hsieh

Reputation: 3393

There's no obvious way to attach m to points in E(Fp). However, you can use variant algorithm of ElGamal such as Menezes-Vanstone Elliptic curve cryptosystem to encode a message in a point, a good reference here(P.31).

As for java code, I suggest you do some work, and post another question on SO when you encounter a problem you really can't solve by yourself.

Upvotes: 1

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