Improving security of lightweith SHA-3 against preimage attacks

In this article we describe the SHA-3 algorithm and its internal permutation in which potential weaknesses are hidden.  The hash can be used for different purposes, such as pseudo-random bit sequences generator, key wrapping or one pass authentication, especially weak devices (WSN, IoT, etc.). Analysis of function showed that successful preimage attacks possible low round hashes, protection from only works with increasing number rounds inside function. When is building lightweight applications, it necessary to apply a small rounds, requires additional security measures. This proposes variant improved protecting against attacks, occur on SHA-3. We suggest using an external randomness sources obtained PRNG application source data permutation.