The wolfSSL library is a lightweight SSL/TLS library written in ANSI C and targeted for embedded, RTOS, and resourceconstrained environments – primarily because of its small size, speed, and feature set. It is commonly used in standard operating environments as well because of its royalty-free pricing and excellent cross platform support.

wolfSSL supports industry standards up to the current TLS 1.3 and DTLS 1.2 levels, is up to 20 times smaller than OpenSSL, and offers progressive ciphers such as ChaCha20, Curve25519, NTRU, Blake2b, and SHA-3 (Keccak). User benchmarking and feedback reports dramatically better performance when using wolfSSL over OpenSSL.

wolfSSL is powered by the wolfCrypt library. wolfCrypt is FIPS 140-2 Level 1 validated, with certificates #2425 & #3389 and a FIPS 140-3 certificate is on the in-process list.

A DO-178C DAL-A certified version is also available for use in avionics applications.
wolfSSL is built for maximum portability, and is generally very easy to compile on new platforms. If your desired platform is not listed under the supported operating environments, please contact wolfSSL.

wolfSSL supports the C programming language as a primary interface. It also supports several other host languages, including Java (wolfSSL JNI/JSSE/JCE), C# (wolfSSL C#), Python (wolfSSL Python), and PHP and Perl (through a SWIG interface).


• SSL 3.0 and TLS 1.0, 1.1, 1.2 and TLS 1.3! (client and server)
• DTLS 1.0 and 1.2 support (client and server)
• Minimum size of 20-100kb
• Runtime memory usage between 1-36kb
• FIPS Ready
• OpenSSL compatibility layer
• OCSP, OCSP Stapling, and CRL support

Multiple Hashing Functions:

  • MD2, MD4, MD5, SHA-1, SHA-2 (SHA-256, SHA-224, SHA-384, SHA-512), SHA-3 (Keccak), BLAKE2b, RIPEMD-160,

Block and Stream Ciphers:

  • AES (CBC, CTR, CFB, GCM, CCM, GMAC, CMAC), Camellia, DES, 3DES, IDEA, ARC4, RABBIT, HC-128, ChaCha20

Public Key Options:


Password-based Key Derivation:

  • Curve25519 and Ed25519
  • ECC and RSA Key Generation
  • X.509v3 RSA and ECC Signed Certificate Generation
  • Mutual authentication support (client/server)
  • PSK (Pre-Shared Keys)
  • Simple API
  • Persistent session and certificate cache
  • PEM and DER certificate support
  • Certificate Manager

Hardware crypto support

  • Intel AES-NI, AVX1/2, RDRAND, RDSEED, SGX, Cavium NITROX, Intel QuickAssist, STM32F2/F4, NXP (CAU, mmCAU, SEC, LTC, CAAM), Microchip PIC32MZ, ARMv8, and more
  • SSL Sniffer (SSL Inspection) Support

Open Source Project Integrations:

  • MySQL, OpenSSH, Apache httpd, Open vSwitch, stunnel, Lighttpd, GoAhead, Mongoose, NGINX, stunnel, haproxy, Wireguard, and more.
  • Linux kernel module support
  • New speedy SP Math implementation
  • Apache TLS 1.3 Sniffer Support