Today, data security is a major problem concerning organizations and indi- viduals. The confidentiality of information is associated with using reliable and robust encryption algorithms in systems. Cyber-attacks on data and systems have become prevalent and sophisticated, and are increasing rapidly; hence, the need for developing robust encryption algorithms is crucial nowadays. This paper proposes a new encryption algorithm using dynamic symmetric key cryptography to encrypt text files. It utilizes a secret key for encryption and decryption processes, where the key’s length is varied depending on the text size. This presented approach gives a trade-off between speed and security, making it suitable for various applications, such as secure messages and files. It utilizes the Genetic Algorithm (GA) only for creating a robust key, which re- duces the complexity and computation overheads. The robustness and effectiveness of the proposed encryption algorithm were evaluated thoroughly by implementing several analysis tests, such as entropy, correlation, and the avalanche effect. The results of these tests demonstrate high randomness and uniformity in the created ciphertext and provide an important contribution to the enhancement of the cryptography field for protecting data.
