ElGamal signature is generated using following steps.

$1.$ Key generation: secret key a with $1<$ a $<$ p$-2$

$2.$ Public key, B$=$ a$"$ mod p; a$,$p are also public.

$3.$ p$->$ large prime number and a generator of $7,*$

$4.$ Calculate signature;

a$.$ repeat

i$.$ Choose random k such that $1<$ k