Efficient Public Key Steganography Secure Against Adaptively Chosen Stegotext Attacks

We define the notion of adative chosen stegotext security. We then construct efficient public key steganographic schemes secure against adaptively chosen stegotext attacks, without resort to any special existence assumption such as unbiased functions. This is the first time such a construction is obtained. Not only our constructions are secure, but also are essentially optimal and have no error decoding. We achieve this by applying a primitive called P-codes.