signalapp/libsignal-protocol-c

Health v2 · maintenance only

Flags: no_releases archived

Adoption not part of the score

1417 stars · 286 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

A C implementation of the Signal Protocol, a ratcheting forward-secrecy encryption protocol for synchronous and asynchronous messaging. It provides the cryptographic primitives used by Signal for end-to-end encrypted communication.

Use cases

• add end-to-end encryption to a chat application
• implement the Signal double ratchet protocol in C
• encrypt messages with forward secrecy
• integrate Signal protocol into a mobile messaging app
• build secure asynchronous messaging

When to choose

• you need the Signal Protocol in a C or C-based mobile/embedded project
• you want battle-tested end-to-end encryption primitives for messaging

When to avoid

• you need an actively developed version - the repo has been superseded by libsignal (Rust) and the last release was 2020
• you want a high-level ready-made chat solution rather than a crypto library
• GPL-3.0 licensing is incompatible with your project

Facets

library · maturity maintenance

cryptography security serialization security privacy cross-platform c signal-protocol end-to-end-encryption double-ratchet forward-secrecy messaging-protocol messaging ios android

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markdown · JSON · MCP: product_card(name="signalapp/libsignal-protocol-c")