In this paper, transformation and substitution based symmetric key encryption algorithm is proposed. Strong correlation between the adjacent pixels can be observed in the multimedia images. The encryption can be made effective by changing both position and value of each pixel in the image. In the proposed algorithm, each pixel position is scrambled using discrete radon transformation (DRT) and pixel value is varied using non chaotic substitution and permutation. The key length used is 64 bits. The secrete key is divided into eight separate keys each of length 8 bits and these are used to change the pixel position along with DRT. Simultaneously, the secret key is subjected for eight set of initial permutations and each set is used to change the pixel value of the image using exclusive-OR operation.