The Democratic National Committee email hack and leak, widely thought to be perpetrated by Russian spies, raise serious concerns about foreign attempts to influence the U.S. election. It is entirely possible that whoever is responsible will leak more files, including Secretary Clinton’s missing State Department emails, before November.

Americans should be careful about accepting the information in these leaks at face value. While many of the emails are authentic, Russian intelligence agencies have a long history, dating back to the Cold War, of using disinformation tactics to influence beliefs. They may release a trove of genuine emails along with some forged or subtly altered emails in order to create negative perceptions of their target beyond what is justified by the unaltered material. If journalists and the American public do not exercise caution over the next several months, they could hand foreign operatives one of their biggest victories ever in November.

The hack also underscores the importance of maximizing transparency so that secrets cannot be used in this manner, of careful attribution of information to original sources, and of computer security, including strong encryption. The information age is an era in which information can be weaponized, and we are all on notice.