  Image Steganography is a thriving research area of information security where
secret data is embedded in images to hide its existence while getting the
minimum possible statistical detectability. This paper proposes a novel magic
least significant bit substitution method (M-LSB-SM) for RGB images. The
proposed method is based on the achromatic component (I-plane) of the
hue-saturation-intensity (HSI) color model and multi-level encryption (MLE) in
the spatial domain. The input image is transposed and converted into an HSI
color space. The I-plane is divided into four sub-images of equal size,
rotating each sub-image with a different angle using a secret key. The secret
information is divided into four blocks, which are then encrypted using an MLE
algorithm (MLEA). Each sub-block of the message is embedded into one of the
rotated sub-images based on a specific pattern using magic LSB substitution.
Experimental results validate that the proposed method not only enhances the
visual quality of stego images but also provides good imperceptibility and
multiple security levels as compared to several existing prominent methods.
