  Steganography is the art and science of writing hidden messages in such a way
that no one apart from the sender and the receiver would realize that a secret
communicating is taking place. Unlike cryptography which only scrambles secret
data keeping them overt, steganography covers secret data into medium files
such as image files and transmits them in total secrecy avoiding drawing
eavesdroppers suspicions. However, considering that the public channel is
monitored by eavesdroppers, it is vulnerable to stego-attacks which refer to
randomly trying to break the medium file and recover the secret data out of it.
That is often true because steganalysts assume that the secret data are encoded
into a single medium file and not into multiple ones that complement each
other. This paper proposes a text steganography method for hiding secret
textual data using two mediums; a Pangram sentence containing all the
characters of the alphabet, and an uncompressed image file. The algorithm tries
to search for every character of the secret message into the Pangram text. The
search starts from a random index called seed and ends up on the index of the
first occurrence of the character being searched for. As a result, two indexes
are obtained, the seed and the offset indexes. Together they are embedded into
the three LSBs of the color channels of the image medium. Ultimately, both
mediums mainly the Pangram and the image are sent to the receiver. The
advantage of the proposed method is that it makes the covert data hard to be
recovered by unauthorized parties as it uses two mediums, instead of one, to
deliver the secret data. Experiments conducted, illustrated an example that
explained how to encode and decode a secret text message using the Pangram and
the image mediums.
