WolfSSL

Key takeaways

WolfSSL belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect WolfSSL to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of WolfSSL from memory before moving on to harder problems.

Reference excerpt

wolfSSL is a small, portable, embedded SSL/TLS library targeted for use by embedded systems developers. It is an open source implementation of TLS (SSL 3.0, TLS 1.0, 1.1, 1.2, 1.3, and DTLS 1.0, 1.2, and 1.3) written in the C programming language. It includes SSL/TLS client libraries and an SSL/TLS server implementation as well as support for multiple APIs, including those defined by SSL and TLS. wolfSSL also includes an OpenSSL compatibility interface with the most commonly used OpenSSL functions.

Platforms 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, Deos, Azure Sphere OS, Zephyr, AIX, and Cesium.

History 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. yaSSL, alternatively, was developed and dual-licensed under both a commercial license and the GPL. yaSSL offered a more modern API, commercial style developer support and was complete with an OpenSSL compatibility layer. The first major user of wolfSSL/CyaSSL/yaSSL was MySQL. 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.

Protocols

The wolfSSL lightweight SSL library implements the following protocols:

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.

Algorithms wolfSSL uses the following cryptography libraries:

wolfCrypt By default, wolfSSL uses the cryptographic services provided by wolfCrypt. 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 (where it can be enabled using a build option). wolfCrypt is FIPS validated and holds two FIPS 140-2 certificates (#2425 and #3389) and two FIPS 140-3 certificates (#4718 and #5041).

NTRU CyaSSL+ includes NTRU public key encryption. The addition of NTRU in CyaSSL+ was a result of the partnership between yaSSL and Security Innovation. 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.

Post-Quantum 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.

Hardware Integration

Secure Element Support wolfSSL supports the following Secure Elements:

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

Technology Support wolfSSL supports the following hardware technologies:

Intel SGX (Software Guard Extensions) - 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)

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

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with WolfSSL

Start with the simplest possible case. Write down what WolfSSL claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to WolfSSL before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about WolfSSL ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of WolfSSL

In research: WolfSSL appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses WolfSSL in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: WolfSSL is common in secondary-school and first-year university syllabi. It links to neighbouring topics C (programming language) libraries, Cryptographic software, Transport Layer Security implementation, so understanding it makes those chapters shorter.
In everyday life: Look for WolfSSL outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study WolfSSL in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what WolfSSL means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain WolfSSL out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is WolfSSL in simple terms?

wolfSSL is a small, portable, embedded SSL/TLS library targeted for use by embedded systems developers. It is an open source implementation of TLS (SSL 3.0, TLS 1.0, 1.1, 1.2, 1.3, and DTLS 1.0, 1.2, and 1.3) written in the C programming language.

Why does WolfSSL matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study WolfSSL?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on WolfSSL.