Since the exchange of encrypted data in interpersonal electronic messages is both rare and easily detected, steganographic techniques are needed to ensure that private communications do not raise suspicion. Previous work in this area is largely inapplicable to environments such as the Internet, as these schemes require the exchange of large data sets in the form of image or sound files, or the sharing of large databases used for the steganographic encoding and decoding, A class of novel systems is presented here which aims to provide a practical solution for steganography over text-based channels with minimal shared information required. The implementation of one of the four presented systems is described and initial experimental results are reported
