Updated at 6:30 p.m. ETFacebook CEO Mark Zuckerberg issued a lengthy post Wednesday on his personal Facebook page promising to protect the data of platform users.He saidFacebook will provide users with tools to show who has access to their data and how it is shared. Facebook will also "restrict developers' data access even further to prevent other kinds of abuse.""We have a responsibility to protect your data, and if we can't, then we don't deserve to serve you," he wrote.The post marks the first public comments made by Zuckerberg about the controversy involving Cambridge Analytica's use of personal data posted by Facebook users.Zuckerberg said there was a "breach of trust" involving Cambridge Analytica, Facebook, and a Cambridge University researcher named Aleksandr Kogan, who created an app to collect data that was later shared with Cambridge Analytica."But it was also a breach of trust between Facebook and the people who share their data with us and expect us to protect it. We need to fix that," he wrote.Zuckerberg said Facebook will restrict third-party developers from accessing data beyond names, profile photos and email addresses. The company will also require developers to sign a contract before asking Facebook users for access to their posts or other private data. Users will also see a tool at the top of their news feeds showing the what apps they have used and will have an easy way to revoke the apps' access to their data.Zuckerberg concluded,