  The needs for steganographic techniques for hiding secret message inside
images have been arise. This paper is to create a practical steganographic
implementation to hide text inside grey scale images. The secret message is
hidden inside the cover image using Five Modulus Method. The novel algorithm is
called (ST-FMM. FMM which consists of transforming all the pixels within the
5X5 window size into its corresponding multiples of 5. After that, the secret
message is hidden inside the 5X5 window as a non-multiples of 5. Since the
modulus of non-multiples of 5 are 1,2,3 and 4, therefore; if the reminder is
one of these, then this pixel represents a secret character. The secret key
that has to be sent is the window size. The main advantage of this novel
algorithm is to keep the size of the cover image constant while the secret
message increased in size. Peak signal-to-noise ratio is captured for each of
the images tested. Based on the PSNR value of each images, the stego image has
high PSNR value. Hence this new steganography algorithm is very efficient to
hide the data inside the image.
