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 VigenÃ¨re Cipher exists in different forms, such as a rectangular matrix with 26 shifted alphabets (tabula recta) and as two concentric discs with a full alphabet each. The letters of the keyword determine how many places the inner disc should be shifted.