Now you are going around in circles, saying the same thing over and over. And whats more, your statements are becoming more vague and ambiguous. "Some sort of secrecy." What sort of secrecy can be maintained about a deal? The details of the deal? Or the fact that a deal has been signed? If it is the former I agree, I have said so myself, but once signed, a deal is public. I am not talking about the pre-deal interest. That is always a secret, or atleast people try to keep it low key affair untill both parties are sure that they will go ahead with the purchase soon or they will be signing a deal soon.
This is the way defence deals work:
First, a potential customer shows interest in some equipment. Then they approach the country of origin for the said equipment. Both sides then work out some basic agreements without making a big fuss about it, like inspecting the weapons, getting briefed by the manufacturers, or even being invited to some live fire testing of sorts. All this is usually kept under the wraps. This is not a deal. This is just showing some interest. It does not mean they will sell/buy.
A lot more happens after that. The potential customer military then does some analysis based on what they say and were presented. Just because a gun fires a bullet, you dont go and buy it for your entire army. You do a feasibility analysis among others. You want to make sure you can afford it, that transitioning to the new weapon will not be difficult, it will work in the environment, spares will be available etc. This happens only after the manufacturer reveals to you some information about the weapon. This kind of knowledge is not available everywhere, only with users and manufacturers. Once the analysis is done, the results and suggestions are put to the govt, who will then decide wether to buy or not. Usually, by this point, one of two things can happen. The media catches wind of it, media have their sources (especially if its some big deal). Or the deal is not significant enough to warrant a report. Once the govt decides to purchase it, they will take it up with the country of origin and sign some MOU or may be even the deal itself. Either of those will make the whole process public.
A deal does not necessarily become public only when the weapons reach BD. If it is a small deal of no strategic consequence (like purchase of a few thousand rifles for SF or ballistic resistant vests for army) sure, people might not even be aware of such deals even after the equipment has arrived. But big ticket items, like ships, fighters, hundreds of tanks/artillery, these cannot be hidden. Some times the interested party and it interest in the weapon is leaked to the media long before any deal is signed.
And ISRO and DRDO? really? they are domestic organizations. I am talking about deals between two countries and you bring up internal R&D organizations. Is your comprehension that weak? May be I am wasting my time explaining to you. I will take my leave from this thread (atleat on this topic).
Ask it from my friend BDforever sheikh hasina dope shop. But he is a good chap. 
