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.
Load index and speed rating are sometimes not mandatory for flotation sizes, but must be for any tire approved for street and highway use. 2- or 3-digit number: Load index; see table below. 1- or 2-digit/letter combination: Speed rating; see table below.