As the communication technology advanced rapidly in recent times, the need for confidential data communication also arose. Here, a computationally feasible encryption/decryption algorithm is proposed to secure data using DNA sequences. The principal objective of DNA algorithm is to reduce big image encryption time. In this algorithm, natural DNA sequences are used as main keys. The image in which secret data is hidden using reversible data hiding (RDH) technique is encrypted twice before transmission. RDH is an information security technology which is extremely helpful in telemedicine. Authentication is necessary for images captured by robots. This can be used for authentication of data. This technique also enables us to embed electronic patient records (EPR) data into medical image before transmission, which can be later recovered on transmission side. The images are divided block-wise before encryption in the proposed scheme. Machine learning helps us to design a support vector machine (SVM), based on which a classification scheme is obtained to group encrypted and original images separately and to recover original image from encrypted image. Copyright © 2021 Inderscience Enterprises Ltd.