In this paper, the secure low-power Internet of Things (IoT) transmission methods for encryption and digital signature are presented. The main goal was to develop energyefficient method to provide IoT devices with data confidentiality, integrity, and authenticity. The cryptograph energy efficient and security algorithms modifications for IoT domain were made. The novelty in our solution is the usage of encryption method popular in the image processing in the domain of the Internet of Things. Proposed modification improves immunity for the brute-force and plain-text attacks. Furthermore, we propose the modifications for hash calculation method to transform it into digital signature calculation method that is very sensitive to input parameters. The results indicate low energy consumption of both methods, however it varies significantly depending on the architecture of the devices.

In the period of 1993-1998 six wells known as being contaminated were monitored 3-6 times per year (a total of 143 samples) for the presence of atrazine, simazine and respective chloro-dealkyl metabolites. Samples were prepared for analysis by solid phase extraction (SPE) and determination was by HPLC/UV or GC/NPD techniques, GC/MSD and HPLC/DAD were employed as secondary (confirmatory) techniques. Residues of analysed compounds were present in more than 90% of samples with exception for DeDiA that was found in 81.6% of samples. The highest concentrations of atrazine, simazine, DeA, DiA, and DeDiA were 16.80; 18.60; 7.49; 2.98 and 3.43 μgil respectively. New inputs of atrazine and simazine were observed in ground water of three wells occasionally, probably resulting from fresh herbicide treatments. In the other wells contamination was rather stagnant at lower levels (0.X mg/I).