French government officials have been revealed as fervent users of Telegram, a messaging app that is frustrating their interior minister with its end-to-end encryption.Telegram's fans include the current head of the French judicial police, Christian Sainte, and his predecessor, Fr\u00e9d\u00e9ric P\u00e9chenard. The app's security has also won over a number of legislators, including the French finance minister, who encourages his team to use it, according to Wednesday's edition of French newspaper Le Canard Enchain\u00e9.Telegram claims over 100 million monthly users of its secure messaging app, but it was the action of just one of them -- Normandy church attacker Adel Kermiche -- that prompted French interior minister Bernard Cazeneuve to call on Tuesday for investigators to be allowed to eavesdrop on Telegram users' conversations.Kermiche used the app to tell a group with 200 members to "download what's coming and share it with everyone," less than an hour before he and an accomplice stabbed a priest to death in northern France last month. The two filmed their action, but it is not known whether they succeeded in transmitting the video.Police now have a transcript of the group chat, presumably either from Kermiche's own phone or that of another group member, but Cazeneuve wants Telegram to provide investigators with much faster access to encrypted chats.Cazeneuve doesn't want to make communications operators like Telegram stop encrypting messages -- merely to assist in decrypting them when asked by law enforcers, he said. Many companies are already providing such assistance, he said, but Telegram is not one of them.Cazeneuve and his German counterpart Thomas de Maiziere called on Tuesday for the European Commission to move ahead with plans for legislation that would require communications operators offering service in Europe to provide law enforcers with access to encrypted messages.The move echoes the view of former British Prime Minister David Cameron, who in January 2015 said it was unacceptable that messaging apps provided "a means of communication between people which even in extremis with a signed warrant from the Home Secretary that we cannot read." Cameron has now been succeeded by his Home Secretary, Theresa May, who has long pushed for greater surveillance powers.But others are more supportive of the availability of encryption too strong even for governments to crack. The head of the French National Data Protection Commission (CNIL), Isabelle Falque-Pierrotin, was among 25 signatories of an open letter defending encryption."Encryption -- like the fundamental freedoms it enables -- is a bulwark against the arbitrary actions of the state. It also protects us from the increasing control of the economic actors in our lives," said the letter,\u00a0published Monday in newspapers in France and Germany and signed by 25 leaders of French businesses and other organizations.