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.
Of all the methods of encryption ever devised, only one has been mathematically proved to be completely secure. It is called the Vernam cipher or one-time pad. The worth of all other ciphers is based on computational security.