Assured security is the desirable feature of modern cryptography. Most of modern cryptography primitives have no provably secure constructions. Their safety is defined on the basis of well-known in the given time cryptanalytic attacks. The duplex construction equipped with one ideal permutation and appropriate security parameters is suitable for building provably secure cryptographic primitives. The constructions can be used for unclassified information of different sensitivity levels protection. Some of them can secure classified information up to the "TOP SECRET" level. The applications based on the duplex construction can be used for key wrapping, authenticated encryption and can work as a pseudo-random bit sequence generator. They are not covered by any known intellectual property.