cryptography - Diffie Hellman generating a result in a range -

i'm using diffie-hellman key exchange method securely generate key use aes cipher (the result hashed make in ideal length). assuming exponent prime of length 2^2048 bits, how can calculate size of base , modulus if want decimal result of length in between (2^6)^32 , (2^6)^40 (i.e. base64 string of length equal or greater 32 , less or equal 40 characters). base want use within range 3

i'm new diffie-hellman exchanges, there restrictions on modulus, base or exponents should aware of?

is there equation can use derive ideal pair lengths, or have pre calculate , store in array.

thanks,

i'm not sure asking about.

for diffie-hellman choose safe or strong prime p between 2^2047 , 2^2048-1 in case, choose element 0 < g < p-1 such g^(p-1) mod *p*=1 g^x mod p≠1 0 < x < p-1 . p , g constant parameters implementation. size of g not matter scheme. key exchange sample 0 < a,b < p-1 uniformly , random, exchange g^a mod p , g^b mod p, , calculate g^ab mod p. because of random choice of a , b result g^ab mod p random 0 < (g^ab mod p) < p-1.

as have noticed can hash g^ab mod p generate short key (256 bit sha256 example).