An Approach for Message Hiding using Substitution Techniques and Audio   Hiding in Steganography
  A crypto system can be used to encrypt messages sent between two communicating parties so that an eavesdropper who overhears the encrypted messages will not be able to decode them. The paper mainly concentrates on the method in which the substitution technique of steganography can been used to hide data in a 24-bit bitmap file. Popular audio hiding techniques based on methods of steganography is also discussed here. 
Debajyoti Mukhopadhyay, Animesh Mukherjee, Surjya Ghosh, Sudipto   Biswas, Poulami Chakraborty
cs.CR