A court in the in the northeastern state of Sergipe granted an appeal filed by the Facebook-owned service on Tuesday, just a day after a 72-hour shutdown of the app was enforced by Judge Marcelo Montalvao. The ban affected more than 100 million WhatApp users across Brazil.
"The service should be freed up in a short time," a spokesman for WhatsApp said on Tuesday afternoon. Following the ruling, mobile operators were instructed to quickly lift the ban.
The service was reportedly blocked on Monday in a bid to force the WhatsApp to turn over records of chats involving an accused drug dealer to investigators.
Second ban since December
This week's temporary ban marked the second time in four months that the messaging service was targeted by a blocking order. In a similar case in December last year, the app was shut down for two days. The decision was overturned 12 hours later, however, following a public outcry and a successful appeal by WhatsApp.
In March this year, Judge Montalvao also ordered the brief arrest of Facebook's vice-president for Latin America, Diego Dzodan, on grounds of failing to comply with a court order to hand over the records. At the time, WhatsApp said it had no way of accessing the encrypted data. Dzodan was jailed but subsequently freed.
Whatsapp announced in April that it had implemented end-to-end encryption for all communications on its network, which is used by some one billion people worldwide. The measures mean that a only the sender and recipents of messages sent on the app are able to read the texts.
The end-to-end encryption protects all text, photo, video and voice communications from eavesdropping, meaning that not only hackers and criminals are closed out but also law enforcement and intelligence agencies, and even WhatsApp itself.
ksb/jm (AFP, dpa)