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.
The load index is identified as a part of the tire size designation or the tire's service description, together with the speed index (e.g. Size designation: 205/60R15 91V - 91V in service description means this tyre can carry maximum 615 kg/1356 lb while going up to the maximum speed of 240kmh/150mph).