wolfSSL

wolfSSL is currently available for Microsoft Windows, Linux, macOS, Solaris, ESP32, ESP8266, ThreadX, VxWorks, FreeBSD, NetBSD, OpenBSD, embedded Linux, Yocto Project, OpenEmbedded, WinCE, Haiku, OpenWrt, iPhone, Android, Wii, and GameCube through DevKitPro support, QNX, MontaVista, Tron variants, NonStop OS, OpenCL, Micrium's MicroC/OS-II, FreeRTOS, SafeRTOS, Freescale MQX, Nucleus, TinyOS, TI-RTOS, HP-UX, uTasker, uT-kernel, embOS, INtime, mbed, RIOT, CMSIS-RTOS, FROSTED, Green Hills INTEGRITY, Keil RTX, TOPPERS, PetaLinux, Apache Mynewt, and PikeOS,^[6] Deos, Azure Sphere OS, Zephyr, AIX, and Cesium.

The genesis of wolfSSL dates to 2004. OpenSSL was available at the time, and was dual licensed under the OpenSSL License and the SSLeay license.^[7] yaSSL, alternatively, was developed and dual-licensed under both a commercial license and the GPL.^[8] yaSSL offered a more modern API, commercial style developer support and was complete with an OpenSSL compatibility layer.^[4] The first major user of wolfSSL/CyaSSL/yaSSL was MySQL.^[9] Through bundling with MySQL, yaSSL has achieved extremely high distribution volumes in the millions.

In February 2019, Daniel Stenberg, the creator of cURL, was hired by the wolfSSL project to work on cURL.^[10]

The wolfSSL lightweight SSL library implements the following protocols:^[11]

• SSL 3.0, TLS 1.0, TLS 1.1, TLS 1.2, TLS 1.3
• DTLS 1.0, DTLS 1.2, DTLS 1.3
• Extensions: Server Name Indication (SNI), Maximum Fragment Length, Truncated HMAC, Application Layer Protocol Negotiation (ALPN), Extended Master Secret, Supported Elliptic Curves
• Ciphersuites: TLS Secure Remote Password, TLS Pre-Shared Key
• Post-quantum cryptography: ML-DSA added to sigAlgs, ML-KEM added to Supported Groups, QSH (deprecated and removed), Dual Algorithm Certificate, and TLS 1.3 Dual Algorithm Authentication Support
• Hybrid TLS Key Establishment Schemes:
  • ECDHE P-256 with Kyber Level 1
  • ECDHE P-384 with Kyber Level 3
  • ECDHE P-521 with Kyber Level 5
• Public Key Cryptography Standards:
  • PKCS #1 - RSA Cryptography
  • PKCS #3 - Diffie-Hellman Key Agreement
  • PKCS #5 - Password-Based Encryption
  • PKCS #7 - Cryptographic Message Syntax (CMS)
  • PKCS #8 - Private-Key Information Syntax
  • PKCS #9 - Selected Attribute Types
  • PKCS #10 - Certificate signing request (CSR)
  • PKCS #11 - Cryptographic Token Interface
  • PKCS #12 - Certificate/Personal Information Exchange Syntax Standard
• QUIC support
• OCSP, OCSP Stapling, CRL
• HPKE (Hybrid Public Key Encryption)
• ECH (Encryption Client Hello)
• x.509v3 Certificates
• Mutual authentication

Protocol Notes:

• SSL 2.0 – SSL 2.0 was deprecated (prohibited) in 2011 by RFC 6176. wolfSSL does not support it.
• SSL 3.0 – SSL 3.0 was deprecated (prohibited) in 2015 by RFC 7568. In response to the POODLE attack, SSL 3.0 has been disabled by default since wolfSSL 3.6.6, but can be enabled with a compile-time option.^[12]

wolfSSL uses the following cryptography libraries:

wolfCrypt#edit

By default, wolfSSL uses the cryptographic services provided by wolfCrypt.^[13] wolfCrypt Provides RSA, DSA, ECC, DSS, Diffie–Hellman, EDH, ECDH-ECDSA, ECDHE-ECDSA, ECDH-RSA, ECDHE-RSA, NTRU (deprecated and removed), DES, Triple DES, AES (CBC, CTR, CCM, GCM, OFB, XTS, GMAC, CMAC), Camellia, IDEA, ARC4, HC-128, ChaCha20, MD2, MD4, MD5, SHA-1, SHA-2, SHA-3, BLAKE2, RIPEMD-160, Poly1305, SM2, SM3, SM4 Random Number Generation, Large Integer support, base 16/64 encoding/decoding, HMAC, PBKDF2, and post-quantum cryptographic algorithms: ML-KEM (certified under FIPS 203) and ML-DSA (certified under FIPS 204).

• ECC curve types: SECP, SECPR2, SECPR3, BRAINPOOL, KOBLITZ
• ECC key lengths: 112, 128, 160, 192, 224, 239, 256, 320, 384, 512, 521

wolfCrypt also includes support for the X25519 and Ed25519 algorithms, as well as the X448 and Ed448 algorithms..

wolfCrypt acts as a back-end crypto implementation for several popular software packages and libraries, including MIT Kerberos^[14] (where it can be enabled using a build option).

wolfCrypt is FIPS validated and holds two FIPS 140-2 certificates (#2425^[15] and #3389^[16]) and two FIPS 140-3 certificates (#4718^[17] and #5041^[18]).

NTRU#edit

CyaSSL+ includes NTRU^[19] public key encryption. The addition of NTRU in CyaSSL+ was a result of the partnership between yaSSL and Security Innovation.^[19] NTRU works well in mobile and embedded environments due to the reduced bit size needed to provide the same security as other public key systems. In addition, it's not known to be vulnerable to quantum attacks. Several cipher suites utilizing NTRU are available with CyaSSL+ including AES-256, RC4, and HC-128.

wolfSSL provides support for a range of post-quantum cryptographic algorithms, including the Kyber Key Encapsulation Mechanism (KEM), hybridized with NIST-recommended ECC curves to maintain FIPS compliance. Supported ML-KEM levels include Level 1 (ML-KEM-512), Level 3 (ML-KEM-768), and Level 5 (ML-KEM-1024). For digital signatures, wolfSSL implements ML-DSA at Levels 2, 3, and 5; FALCON at Levels 1 and 5; and SLH-DSA, LMS/HSS, and XMSS/XMSS^MT. The library also supports hybrid TLS key exchange schemes, combining ECDHE with ML-KEM at corresponding security levels as well as dual-algorithm certificates and TLS 1.3 dual-algorithm authentication.

Secure Element Support#edit

wolfSSL supports the following Secure Elements:

• STMicroelectronics STSAFE
• Microchip CryptoAuthentication ATECC508A
• Microchip TA100
• NXP EdgeLock SE050 Secure Element

Technology Support#edit

wolfSSL supports the following hardware technologies:

• Intel SGX (Software Guard Extensions)^[20] - Intel SGX allows a smaller attack surface and has been shown to provide a higher level of security for executing code without a significant impact on performance.
• NXP CAAM (Cryptographic Acceleration and Assurance Module) on i.MX6 (QNX), i.MX8 (QNX/Linux), RT1170 FreeRTOS
• ARM TrustZone CryptoCell 310
• MAXQ1065/1080 RNG
• MAX32665 and MAX32666 TPU (Trust Protection Unit)

wolfSSL is dual licensed: under both the GPL-3.0-or-later license and commercial licensing.

• Transport Layer Security
• Comparison of TLS implementations
• Comparison of cryptography libraries
• GnuTLS
• Network Security Services
• OpenSSL

1. ^ "wolfSSL ChangeLog". 10 August 2017.
2. ^ "Release 5.9.4". 27 September 2026. Retrieved 27 September 2026.
3. ^ "LICENSING". GitHub.
4. ^ a b wolfSSL – Embedded Communications Products
5. ^ "What You Need to Know About the TLS 1.3 Protocol and wolfSSL's SSL/TLS Libraries". www.allaboutcircuits.com. Retrieved 2018-12-28.
6. ^ "wolfSSL Embedded SSL/TLS Library | wolfSSL Products". 4 August 2017. Retrieved 2019-01-31.
7. ^ OpenSSL: Source, License
8. ^ wolfSSL – License
9. ^ "MySQL, Building MySQL with Support for Secure Connections". Archived from the original on 2017-07-06. Retrieved 2016-06-12.
10. ^ Daniel Stenberg, founder and Chief Architect of cURL, joins wolfSSL
11. ^ wolfSSL – Docs | CyaSSL Manual – Chapter 4 (Features)
12. ^ "wolfSSL 3.6.6 is Now Available".
13. ^ wolfSSL – Docs | wolfSSL Manual – Chapter 10 (wolfCrypt Usage Reference)
14. ^ Kerberos: The Network Authentication Protocol
15. ^ [title=Certificate #2425|url=https://csrc.nist.gov/projects/cryptographic-module-validation-program/Certificate/2425
16. ^ [title=Certificate #3389|url=https://csrc.nist.gov/Projects/cryptographic-module-validation-program/Certificate/3389
17. ^ [title=Certificate #4718|url=https://csrc.nist.gov/projects/cryptographic-module-validation-program/certificate/4718
18. ^ [title=Certificate #5041|url=https://csrc.nist.gov/projects/cryptographic-module-validation-program/certificate/5041
19. ^ a b NTRU CryptoLabs Deprecated link archived 2013-02-02 at archive.today
20. ^ wolfSSL – wolfSSL with Intel® SGX

• wolfSSL/CyaSSL Homepage
• wolfSSL Now With ChaCha20 and Poly1305