docs: def server_seed(v, b=random.randrange(0, 1 << SRP_KEY_SIZE)):
      """
          B: Server public key
          b: Server private key
      """
      N, g, k = get_prime()
      if DEBUG:
          b = DEBUG_PRIVATE_KEY
      gb = pow(g, b, N)
      kv = (k * v) % N
      B = (kv + gb) % N
      if DEBUG_PRINT:
          print("v", binascii.b2a_hex(long2bytes(v)), end='\n')
          print('b=', binascii.b2a_hex(long2bytes(b)), end='\n')
          print("gb", binascii.b2a_hex(long2bytes(gb)), end='\n')
          print("k", binascii.b2a_hex(long2bytes(k)), end='\n')
          print("v", binascii.b2a_hex(long2bytes(v)), end='\n')
          print("kv", binascii.b2a_hex(long2bytes(kv)), end='\n')
          print('B=', binascii.b2a_hex(long2bytes(B)), end='\n')
      return B, b