Signal scores 5/5 for encryption, 5/5 for privacy, and 5/5 for track record. Overall safety score: 5/5.

What are the privacy concerns with Signal?

Signal security review covering end-to-end encryption, metadata protection, and why it is the gold standard.

Has Signal been hacked before?

See our detailed analysis of Signal's past security incidents and track record at The Opt-Out Project.

Is Signal Safe? Security Review

Name: Is Signal Safe? Security Review
Item: Signal
Rating: 5
Author: The Opt-Out Project

Category: Messaging Company: Signal Technology Foundation Reviewed February 10, 2026

5/5

Overall Safety Score

★ ★ ★ ★ ★

Verdict: Signal is the most secure mainstream messaging app available. It collects virtually no user data, uses best-in-class encryption, and is operated by a non-profit foundation with no advertising business model.

Signal is a non-profit encrypted messaging app widely considered the gold standard for private communication. Its Signal Protocol powers encryption in WhatsApp, Google Messages, and Facebook Messenger.

Security Ratings Breakdown

Category	Score	Rating
Encryption	5/5
Privacy	5/5
Track Record	5/5

Security Features

End-to-end encryption for all messages, calls, and video calls
Signal Protocol (open-source, independently audited)
Sealed sender to protect metadata
Disappearing messages
Screen security (blocks screenshots)
Registration Lock (PIN protection)
No ads, no tracking, non-profit

Privacy Concerns

Requires a phone number for registration (though username support was added)
Centralized server infrastructure (not federated)
Contact discovery requires sharing phone number hashes

Past Security Incidents

2022 Twilio breach exposed phone numbers of approximately 1,900 Signal users (Signal's encryption prevented message exposure)
Signal's response demonstrated its minimal data retention: it could only confirm registration status and last connection date