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aws/s2n-tls

Free

An implementation of the TLS/SSL protocols

FreeFree tier
Type
Open Source
Company
Amazon Web Services

About aws/s2n-tls

s2n-tls is a C99 implementation of the TLS/SSL protocols developed by AWS, designed to be simple, small, fast, and with security as a priority. Released under the Apache License 2.0, it supports multiple platforms including Ubuntu, Amazon Linux, NixOS, OpenBSD, FreeBSD, macOS, and Windows (via MSYS2/MinGW). The library includes Doxygen-based documentation, a usage guide, and Rust bindings. It is continuously tested on Tier 1 and Tier 2 platforms. The name 's2n-tls' is short for 'signal to noise', reflecting the encryption process.

Key Features

C99 implementation of TLS/SSL protocols
Simple, small, and fast design
Security as a priority
Apache License 2.0 open source
Cross-platform support: Ubuntu, Amazon Linux, NixOS, OpenBSD, FreeBSD, macOS, Windows (MSYS2/MinGW)
Comprehensive Doxygen documentation and usage guide
Rust bindings available
Continuous integration testing on Tier 1 and Tier 2 platforms

Pros & Cons

Pros
  • Open source with permissive Apache 2.0 license
  • Security-focused design
  • Well-documented API and usage guide
  • Cross-platform and portable (C99)
  • Backed by AWS with active maintenance
Cons
  • Requires an external libcrypto library (e.g., OpenSSL) as a build dependency
  • Limited to C99; other languages require bindings

Best For

Embedding TLS/SSL in software applicationsSecure network communicationBuilding secure cloud infrastructureIntegration into operating systems or embedded systems