In this article, we have explained the RSA public-key cryptosystem initiate by Rivest and Hill Chiper cryptosystem initiate by Lester. Hill for coding and decoding the text. To explain these we apply the Euler-phi function, congruence, and simple Matrix Application in cryptography to decode and encode the message. In our analyses, we have collaborated two cryptosystems which is more assured than standard cryptographic process such as Ceaser cipher. We apply both secret-key cryptography and public-key cryptography which differ from standard cryptography. In our presentation, we use two keys for coding and two for decoding.
Proposal of a sustainable strategic positioning matrix: application in the development of a product / Proposta de uma matriz de posicionamento estratégico sustentável: aplicação no desenvolvimento de um produto