India has given Blackberry phone maker RIM a deadline of 31 August to give the government access to all of its services or face being shut down.
The country is reported to be considering similar bans on Skype and Google services, according to the Financial Times.
RIM has issued a statement outlining when it claims "lawful" access to encrypted data is acceptable.
It has no "special deals" with specific countries, it claims.
In the statement, RIM sets out four principles which underpin any request for access to data sent and received by Blackberry handsets.