One of the staunchest defenders of digital rights on Capitol Hill rallied allies for a battle in Congress over secure communications technology.

Addressing a “Crypto Summit” hosted by the Washington-based technology group Access, Rep. Zoe Lofgren (D-Calif.) on Wednesday criticized members of the law enforcement community who are pushing policies she has been fighting—mandated pathways to encrypted communications, which she called “technologically unfeasible.”

“Even if a backdoor is created with the best of intentions, it’s only a matter of time before a hacker finds and exploits it,” Lofgren told the summit Wednesday. She said a carve-out “puts the data security of everyone on the internet at risk.”

“I see a big fight ahead of us,” she added.

Lofgren said that Edward Snowden’s revelations about US spies exploiting digital security weaknesses had already created a “crisis of trust” among computer users that can only be rectified by lawmakers taking a stand to defend cryptology

In June, she reached across the aisle and teamed up with Rep. Thomas Massie (R-Ky.) in to pass legislation in the House that prevents government agencies from forcing companies to insert “backdoors” into encrypted channels.

The bill was also introduced in response to lobbying efforts in the opposite direction by FBI Director James Comey. Comey has been pressuring lawmakers to help the bureau track communications of people who are “going dark”—or relying on encrypted communications platforms.

During a hearing in March, he asked lawmakers for a “legislative fix” that would allow cops to access data secured via end-to-end-encryption, which often cannot even be deciphered by the company that offers the service.

Comey has changed his tune in the months since, however, telling the Senate Intelligence Committee last week that “there has not yet been a decision whether to seek legislation.”

Also delivering a keynote address at the Crypto Summit alongside Rep. Lofgren, was David Kaye, the United Nations Special Rapporteur on the promotion and protection of the right to freedom of opinion and expression.

Kaye released a report in May, which concluded that most governments’ efforts to restrict encryption failed to meet the test of necessity and proportionality. The legislative efforts, he said, do “significant—and I believe disproportionate damage—to the freedom of expression.”

Kaye called on tech companies to offer more default encryption services, and asked attendees to take action to defend the technology.

“I hope that activist sand advocates and academics review the report, make use of its findings,” Kaye said.