"CISA isn't a cybersecurity bill," Snowden wrote during the Q&A. "It's not going to stop any attacks. It's not going to make us any safer. It's a surveillance bill."

Supporters of CISA—including Sens. Dianne Feinstein (D-Calif.) and Richard Burr (R-N.C.)—say the bill would make it easier for tech companies to share data in cases of security breaches and other digital attacks. But critics say there aren't enough safeguards in place to protect user privacy and the bill only works to serve intelligence agencies in domestic surveillance operations.

"What it allows is for the companies you interact with every day—visibly, like Facebook, or invisibly, like AT&T—to indiscriminately share private records about your interactions and activities with the government," Snowden wrote on Monday. "CISA allows private companies to immediately share a perfect record of your private activities the instant you click a link, log in, make a purchase, and so on—and the government with reward for doing it by granting them a special form of legal immunity for their cooperation."