You have not done any offence by recording some voice. But it may be an offence in that recorded voice you offered some bribe, illegal gratification.
You can produce the recorded conversation as evidence. But some difficult steps have to be taken to prove its authenticity.
It is quite normal in India, the messanger is shoot but not the sender. What you saw in the case of "Tehalka", where they exposed NDA government in Defence Scandal? The editorial staff are even today making rounds to the court of law for using prostitutes to reveal defence scandal. Similar is the case, in "no confidence motion" came up before Parliament on the issue of "nuclear agreement" with U.S.A. The party in power purchased the MPs to win the no confidence and the members of parliament and the secretarial staff of some MPs are being punished for exposing this scandal by ehibiting the currency notes, where as the govenrment which made corrupt practices won the no confidence motion. This is the law of land.