A valid digital signature gives a recipient reason to believe that the message was created by a known sender (authentication), that the sender cannot deny having sent the message (non-repudiation), and that the message was not altered in transit (integrity).
Load index is an assigned number that corresponds with the load-carrying capacity of a tire. Most passenger car tire load indexes range from 75 to 100, but a few carry more. You'll also find the maximum load elsewhere on the tire sidewall, both in lbs and kg.
1 The third number is the wheel size: 16 indicates the wheel diameter in inches the tire is designed to fit. In this case a 16-inch wheel.  The last number refers to the load index: In this case, 67 is the load index designation. In this example 67 informs the consumer that the tireâs maximum load capacity is 661 lbs.