A fiber, a single filament of natural material, such as cotton, linen or wool, or artificial material such as nylon, polyester, metal or mineral fiber, or man made natural fibre like Viscose, Modal & Excel is measured in terms of linear mass density, the weight of a given length of fiber.
The vernam cipher, sometimes known as the 'one time pad', is a stream cipher, which providing certain requirements are met, can be theoretically unbreakable.
The other critical aspect of the Vernam cipher is the randomness of the pad sequence. An event sequence can be said to be truly random if it is impossible to predict the next event in the sequence even if the entire state of the generating process up to that point is known.