import string
import random


def randomString(stringLength=16):
    """Generate a random string of fixed length
    We use this to randomize the SNI, in order for the proxy/NGFW to not present a cached certificate.
    """
    letters = string.ascii_lowercase
    lettersAndDigits = string.ascii_letters + string.digits
    return ''.join(random.choice(lettersAndDigits) for i in range(stringLength))