Ever since manual work is overtaken by technology, the rapid advancement in the technologies for performing all kinds of work online has created new possibilities for the organizations and institutions of alltypes. But this has also created opportunities for attackers and opponents by reducing the powers of existing controls over data sharing. All private, public, and any other sectors are using the internet for sharing their data. Transmission of unencrypted data over the internet is not secure as it poses many privacy concerns as they can be easily hacked and misused by any unintended person. So, everyone is concerned about safe and secure ways of data transmission in order to avoid leak of private data, as hackers always tryto chasethe transmitted data and to recoverit, and therefore various differenttechniques are developedin ordertomake datatransmission more secure. Encryption is essential to protect and prevent such lapses in the transmission of sensitive information over the internet and any other networks. In this paper, the author has worked on a better version of Caesar cipher and invented a method in which modular arithmetic is used to convert plaintext into ciphertext in order to amplify and to bolster up the security of the sensitive data or information, and the author composed the decryption method in such a way that it is no way related to encryption by involving the divisibility tests and arithmetic modulo.