Publimark is a command line tool to secretly embed text in an audio file.
Version: 0.1.3Publimark is a command line tool to secretly embed text in an audio file. Like cryptography, Publimark project uses a pair of keys: the public one can be shared, whereas the private one must be kept secret.
Operating System: Linux
Anybody can send a steganographic message, but only the private key owner will be able to read it. Marked audio files are still playable without any noticeable difference.
How does it work
It exists a lot of steganographic schemes. Some of them are very efficient (i.e. they can transmit a large amount of data without making stego-file suspicious), but they are based on a private key. Before any secret communication, you must transmit the secret key, which is often unsecured. If someone intercepts the private key, they will be able to read the secret communication.
Publimark does not need this confidential key-sharing process. Like advanced cryptographic algorithms, it uses a pair of keys. The first one – the public key – must be shared, whereas the private one must be kept secret. Everybody can then send you a secret message (if he knows the public key, of course), but only the secret key owner – you – can read it.
A first practical attempt to make an efficient public key steganographic scheme was done by P. Guillon and T. Furon . It is based on two phases. The sender chooses a random key, denoted seed. It is encoded with the public key – i.e. se = encode(seed, pub) – and transmitted. The second step consists in transmitting the message using an efficient private key steganographic algorithm (authors use SCS ), with private key seed.
The main problem is the first step. How a key can be transmitted without any statistical artifact on host data? Authors discovered that such a transmission is possible for uniformly distributed cover data. They then use a compressor (to transform a given p.d.f. to a uniform one).
This framework (two phases) is also used by Publimark. But it uses a TCQ-like space partitioning to transmit seed. It works for any p.d.f. (whereas compressor is designed for only one case) and is much easier to implement. Here is an article that explains how it works.
What's New in This Release:
· This release adds subtle changes to be compatible with Botan 1.6 and MacOS Tiger.