Signal - Private Messenger Security & Privacy Scorecard

Signal

What This Means for You

Your messages, calls, and media are protected by end-to-end encryption, and Signal collects no analytics, runs no ads, and shares none of your communications data with any advertiser or data broker.

Recommendation: Very Secure

Signal combines exceptional end-to-end encryption with zero analytics and strict local data protection. Ideal for users who prioritize privacy in sensitive communications.

Best For: Privacy-conscious users wanting encrypted, zero-tracking messaging with no third-party data collection

Key Findings

Data Security - 5 findings (1 low, 4 info)

Network Security - 3 findings (1 low, 2 info)

Code Safety - 5 findings (1 low, 4 info)

Privacy - 3 findings (3 info)

Privacy Concerns

What Data is Collected

• Phone number: shared with Signal's servers to create and verify your account
• Diagnostic logs: shared with Signal's servers only when you manually choose to submit them for support purposes
• Message content, call audio and video, contacts, and attachments: stay on your device and are end-to-end encrypted in transit; Signal cannot access this content

Third-Party Data Sharing

The following third parties may receive your data:

• MobileCoin - payment network that processes transactions if you use the optional Signal Payments feature
• Google Maps - may receive your IP address and approximate location if you view a shared location within a conversation

Understanding the Scores

Security: 98/100
Privacy: 99/100

Security Breakdown

• Data Security: 99/100 - All data stored on your device is encrypted with a strong library, and the most protective iOS file class is applied by default across the entire app.
• Network Security: 99/100 - All connections use strong encryption with an additional application-layer certificate validation mechanism that goes beyond standard iOS transport security.
• Code Safety: 100/100 - Signal applies enterprise-grade memory safety protections, uses no embedded browser with native code access, and takes meticulous care in how it handles system integrations.

Privacy Breakdown

• Data Collection: 100/100 - No analytics, advertising identifiers, or behavioral tracking are present. The only data tied to your account is your phone number.
• Data Sharing: 100/100 - No third-party analytics, advertising, or data-broker services receive your information. All bundled libraries are functional open-source components with no data-sharing capability.
• User Control: 99/100 - Diagnostic log uploads are always user-initiated. Encryption keys are stored in the secure device keychain and cannot leave your device via cloud backup.

Positive Security Features

• All local data is encrypted with a strong library, and keys are managed exclusively by the secure device keychain with no iCloud sync
• The most protective iOS file protection class is applied across the entire app by default, keeping your data inaccessible when the device is locked
• Enterprise-level memory safety protections are active, well beyond what standard App Store builds use
• A custom application-layer certificate validation mechanism provides an additional security layer on top of iOS transport security
• External links open in a fully isolated browser session with no connection to the app's data or identity
• Zero analytics, advertising, attribution, or crash-reporting services are bundled in the app
• App Store privacy declarations are complete and accurate across all components, with tracking explicitly disabled in every manifest
• Encryption keys are locked to your specific device and cannot be migrated or synced via cloud services

Areas for Improvement

GDPR / CCPA Compliance

The app's privacy practices could be strengthened by:

1. Apple Music Permission Cleanup
   The app declares an Apple Music permission but no corresponding Apple Music functionality was found. Removing unused permission declarations keeps the permissions list accurate for users reviewing what the app requests.

2. iCloud Key-Value Storage Clarification
   The app holds an iCloud key-value storage entitlement whose active usage could not be confirmed. If not actively used, removing the entitlement would reduce the theoretical surface area for unexpected cross-device data exposure.

Security Enhancements

1. Network Configuration Narrowing
   The app's network configuration allows unencrypted connections to Signal's own domains and all their subdomains. Narrowing this to only the specific subdomains that require it would reduce reliance on the secondary certificate validation layer for those requests.

2. Device Transfer Channel Verification
   The device-to-device account transfer feature uses local network technology whose encryption mode could not be confirmed from this analysis. Making the encryption configuration explicit in the binary would allow it to be verified without access to the source code.

Technical Context

App Type: End-to-end encrypted messaging, sensitive personal communications
Classes Analyzed: 1,626
Third-Party Services: 2 (MobileCoin for payments, Google Maps for location display; no analytics, ad, or tracking services)
Context Tags: messaging, sensitive_data, contacts

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About This Analysis

This security analysis was conducted by CITT (Can I Trust That), an independent security analysis service. We perform static code analysis on iOS applications to help users make informed decisions about app security and privacy.

App Details

Developer: Signal Messenger, LLC
Version: 8.15 (build 1655)
Analysis Date: 2026-06-17
Package: org.whispersystems.signal

Analysis Limitations

• Static analysis only (code review without running the app)
• Based on IPA version 8.15 analyzed on 2026-06-17
• May not reflect server-side security controls
• Cannot detect all runtime behaviors