In recent world, everybody wants to transmit their valuable information securely without the knowledge of the intruder. One of the way-out is steganography. Using steganography, information can be transferred using cover media. Cover media can be image, video, sound, or text. Most popularly used cover media is a digital image because the slight modification of a cover image is difficult to distinguish by human eye. İn our paper, the proposed method uses Sudoku puzzle to hide secret message within a cover image. The benefit of using Sudoku is if any intruder modifies the secret message then receiver will be able to detect this. In this proposed method, the length of the secret message is directly proportional to the resolution of the cover image. The proposed method has been developed to transmit the secret message more securely. Here, a single 9 × 9 Sudoku puzzle is used, and this Sudoku puzzle is embedded within the image by modifying the RGB value of pixels. Within each cell of the Sudoku puzzle we indirectly store one character of the secret data; hence, the intruder cannot fetch the secret message directly, to detect if intruder modifies the secret message or not, and associated information is stored which makes the proposed method more reliable than other existing methods. This proposed method is better than the existing methods because it uses RGB value, whereas the most of the methods used grayscale value. © 2018, Springer Nature Singapore Pte Ltd.