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.
cipher. n. 1. a method of secret writing using substitution or transposition of letters according to a key. 2. a secret message. 3. the key to a secret message. 4. (Mathematics) an obsolete name for zero 1. 5.