def randomByteString(len):
 ll = int(((len / 8) + int(((len % 8) > 0))))
 return ''.join([struct.pack('!Q', random.getrandbits(64)) for _ in xrange(0, ll)])[:len]

def randomByteString ( len ) : ll = int ( ( ( len / 8 ) + int ( ( ( len % 8 ) > 0 ) ) ) ) return '' . join ( [ struct . pack ( '!Q' , random . getrandbits ( 64 ) ) for _ in xrange ( 0 , ll ) ] ) [ : len ]
generate a string of random bytes .