Ok, it's kind of stupid question, but I want to make sure.
What is the length of the ElGamal cipher? It's equal to the size of 2 elements of the cyclic group, right? But lengths of elements are NOT always the same, right?
Toy example:
We pick p = 23, q = 11 (p = 2q+1), our generator is 18, so G = {18,2,13,4,3,8,6,16,12,9,1}. Sekret key x is 6 (a random form {1,q-1}), h = g^x mod p = 8.
Now is the fun part:
1) Encryption of m = 18 with r = 8 is (16,3)
2) Encryption of m = 18 with r = 7 is (6,9)
Am I getting different length ciphers because it's the toy example or what? Padding? All group elements have identical length? I haven't noticed any length difference in the real ElGamal implementation.