In this paper, Quaternion Julia set is used to generate real-time based symmetric keys for cryptography. The number of iterations, complex number and control value are the determining parameters of dynamically varying quaternion Julia image structure. The considered parameters are initialised in the proposed model of symmetric key generation during the establishment of communication between hosts. The model generates variable length, dynamic, one time usable key from quaternion Julia image to encrypt or decrypt data without involving the exchange of key. The time stamp used during the initialization process makes the quaternion Julia image to be different in real-time. The instantaneous key is generated at the hosts independently in a synchronous fashion to enhance the complexity in cryptanalysis. The proposed model has wide range of applications from low confidential to high confidential data transfer in two party and multi-party scenarios.

Cryptography, Quaternion Julia set, Symmetric key generation, Real-time encryption