Today using encryption can raise a flag to who is spying your information flow. The fact of encrypting one of your message can says that this message is of some importance. Why? Because in these days, message encryption is relatively rare. Some will says that this is not true; all transactions are encrypted and many sites use SSL or other encryption negotiation protocols to hide your requests and transactions. The problem is deeper. With information flow analysis, you can easily infer meaning of a flow of information. We’ll take an internet information flow for our example. The internet works because all the communications are done with some type of protocols. You have one to see web pages, another to get your emails, another to send your emails, one to send files, etc. All these protocols can be view as signatures. If someone is spying your internet information flow, he can easily discard all the data you send over the internet except your emails. Why he can do this? Because he know the signature of this specific flow of information. If you encrypt one of your email message, he’ll be able to easily infer that this message is of some importance; except if you encrypt all of your emails (in this case you have another information flow pattern). He can infer this information because you changed your communication pattern.

It’s why stenography can be interesting, because you can hide and change your signature. The problem is that by doing this you can raise suspicious by possibly changing your communication pattern again. Nothing is perfect in this world!