Enciphering on the basis of the sums with products of weight and free components as summands

The purpose of the given paper is reviewing of mathematical resources of enciphering of the source text, allowing to ensure the simplicity of appropriate decryption; the source text is a sequence of integer weight coefficients. The composer of the cipher checks how the condition of separability of these coefficients is satisfied. The selection rule provides usage of operations of the lower or upper roundoff. The generated cipher is represented by the values of the finite sums.