  Steganography is an information hiding technique in which secret data are
secured by covering them into a computer carrier file without damaging the file
or changing its size. The difference between steganography and cryptography is
that steganography is a stealthy method of communication that only the
communicating parties are aware of; while, cryptography is an overt method of
communication that anyone is aware of, despite its payload is scribbled.
Typically, an irrecoverable steganography algorithm is the algorithm that makes
it hard for malicious third parties to discover how it works and how to recover
the secret data out of the carrier file. One popular way to achieve
irrecoverability is to digitally process the carrier file after hiding the
secret data into it. However, such process is irreversible as it would destroy
the concealed data. This paper proposes a new image steganography method for
textual data, as well as for any form of digital data, based on adjusting the
brightness of the carrier image after covering the secret data into it. The
algorithm used is parameterized as it can be configured using three different
parameters defined by the communicating parties. They include the amount of
brightness to apply on the carrier image after the completion of the covering
process, the color channels whose brightness should be adjusted, and the bytes
that should carry in the secret data. The novelty of the proposed method is
that it embeds bits of the secret data into the three LSBs of the bytes that
compose the carrier image in such a way that does not destroy the secret data
when restoring back the original brightness of the carrier image. The
simulation conducted proved that the proposed algorithm is valid and correct.
