wolfSSL

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.[3][4]

wolfSSL

Developer(s)	Todd Ouska
Initial release	February 19, 2006 (2006-02-19)[1]
Stable release	4.4.0 (April 22, 2020 (2020-04-22)[2]) [±]
Repository	github.com/wolfssl/wolfssl
Written in	C
Operating system	Multi-platform
Type	Cryptography library
License	GPLv2 or commercial
Website	www.wolfssl.com

A predecessor of wolfSSL, yaSSL is a C++ based SSL library for embedded environments and real time operating systems with constrained resources.

Platforms

wolfSSL is currently available for Win32/64, Linux, macOS, Solaris, Threadx, VxWorks, FreeBSD, NetBSD, OpenBSD, embedded Linux, Yocto Project, OpenEmbedded, WinCE, Haiku, OpenWrt, iPhone, Android, Nintendo 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.[5]

History

The genesis of yaSSL, or yet another SSL, dates to 2004. OpenSSL was available at the time, and was dual licensed under the OpenSSL License and the SSLeay license.[6] yaSSL, alternatively, was developed and dual-licensed under both a commercial license and the GPL.[7] yaSSL offered a more modern API, commercial style developer support and was complete with an OpenSSL compatibility layer.[3] The first major user of wolfSSL/CyaSSL/yaSSL was MySQL.[8] Through bundling with MySQL, yaSSL has achieved extremely high distribution volumes in the millions.

Protocols

Main article: Transport Layer Security

The wolfSSL lightweight SSL library implements the following protocols:[9]

• SSL 3.0, TLS 1.0, TLS 1.1, TLS 1.2, TLS 1.3
• DTLS 1.0, DTLS 1.2, DTLS 1.3

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.[10]

Algorithms

wolfSSL uses the following cryptography libraries:

wolfCrypt

By default, wolfSSL uses the cryptographic services provided by wolfCrypt.[11] wolfCrypt Provides RSA, ECC, DSS, Diffie–Hellman, EDH, NTRU, DES, Triple DES, AES (CBC, CTR, CCM, GCM), Camellia, IDEA, ARC4, HC-128, ChaCha20, MD2, MD4, MD5, SHA-1, SHA-2, SHA-3, BLAKE2, RIPEMD-160, Poly1305, Random Number Generation, Large Integer support, and base 16/64 encoding/decoding. An experimental cipher called Rabbit, a public domain software stream cipher from the EU's eSTREAM project, is also included. Rabbit is potentially useful to those encrypting streaming media in high performance, high demand environments.

wolfCrypt also includes support for the recent Curve25519 and Ed25519 algorithms.

wolfCrypt acts as a back-end crypto implementation for several popular software packages and libraries, including MIT Kerberos[12] (where it can be enabled using a build option).

NTRU

CyaSSL+ includes NTRU[13] public key encryption. The addition of NTRU in CyaSSL+ was a result of the partnership between yaSSL and Security Innovation.[13] 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.

SGX

wolfSSL supports use of Intel SGX (Software Guard Extensions).[14] Intel SGX allows for a smaller attack surface area and has been shown to provide a higher level of security for executing code without a significant negative impact on performance.

Hardware Acceleration Platforms Supported

Supported trusted elements

Currently, wolfSSL has the following as supported trusted elements:

• STSAFE
• ATECC508A

Hardware encryption support

The following tables list wolfSSL's support for using various devices' hardware encryption with various algorithms.

AES cipher modes

Device	AES-GCM	AES-CCM	AES-CBC	AES-ECB	AES-CTR
Intel AES-NI (Xeon and Core processor families)	All	All	All	All	All
Freescale Cryptographic Accelerator and Assurance Module (CAAM)		All	All	All	All
Freescale Coldfire SEC (NXP MCF547X and MCF548X)			All
Freescale Kinetis MMCAU K50, K60, K70, and K80 (ARM Cortex-M4 core)	All	All	All	All
STMicroelectronics STM32 F1, F2, F4, L1, W Series (ARM Cortex - M3/M4)			All		All
Cavium NITROX (III/V PX processors)			All
Microchip PIC32 MX/MZ (Embedded Connectivity)	All		All		All
Texas Instruments TM4C1294 (ARM Cortex-M4F)	All	All	All	All	All
Nordic NRF51 (Series SoC family, 32-bit ARM Cortex M0 processor core)				128-bit
ARMv8	All		All		All
Intel QuickAssist Technology	All		All
Freescale NXP LTC	All	All	All	All	All
Xilinx Zynq UltraScale+	256-bit

- "All" denotes 128, 192, and 256-bit supported block sizes

DES/3DES cipher modes

Device	DES-CBC	DES-ECB	3DES-CBC
Freescale Coldfire SEC (NXP MCF547X and MCF548X)	64 bit		192 bit
Freescale Kinetis MMCAU K50, K60, K70, and K80 (ARM Cortex-M4 core)	64 bit		192 bit
STMicroelectronics STM32 F1, F2, F4, L1, W Series (ARM Cortex - M3/M4)	64 bit	64 bit (encrypt)	192 bit
Cavium NITROX (III/V PX processors)	192 bit
Microchip PIC32 MX/MZ (Embedded Connectivity)	64 bit		192 bit
Texas Instruments TM4C1294 (ARM Cortex-M4F)	64 bit		192 bit

Stream ciphers

Device	RC4	ChaCha20
AVX1/AVX2 (Intel and AMD x86)		Supported
Cavium NITROX (III/V PX processors)	2048 bit max.

Hashing algorithm support

Device	MD5	SHA1	SHA2	SHA-256	SHA-384	SHA-512
AVX1/AVX2 (Intel and AMD x86)				Supported	Supported	Supported
Freescale Kinetis MMCAU K50, K60, K70, and K80 (ARM Cortex-M4 core)	Supported	Supported		Supported
STMicroelectronics STM32 F1, F2, F4, L1, W Series (ARM Cortex - M3/M4)	Supported	Supported
Microchip PIC32 MX/MZ (Embedded Connectivity)	Supported	Supported		Supported
ARMv8				Supported
Intel QuickAssist Technology	Supported	Supported	Supported
Freescale NXP LTC		Supported		Supported
Xilinx Zynq UltraScale+					Supported

Key operations: generation and exchange, elliptic curve cryptography

Device	RSA	ECC	ECC-DHE	Curve25519	Ed25519
Cavium NITROX (III/V PX processors)	512 - 4096 bit	NIST Prime 192, 224, 256, 384, 521
Microchip/Atmel ATECC508A (compatible with any MPU or MCU including: Atmel SMART and AVR MCUs)		256 bit (NIST-P256)
Intel QuickAssist Technology	512 - 4096 bit	128, 256 bit
Freescale NXP LTC	512 - 4096 bit	128, 256 bit	128, 256 bit	256 bit	256 bit
Xilinx Zynq UltraScale+	2048 - 4096 bit

MAC algorithms

Device	HMAC-MD5	HMAC-SHA1	HMAC-SHA2	HMAC-SHA256	SHA-3	Poly1305
AVX1/AVX2 (Intel and AMD x86)						Supported
Cavium NITROX (III/V PX processors)	Supported	Supported		Supported	Supported
Microchip PIC32 MX/MZ (Embedded Connectivity)	Supported	Supported		Supported
Intel QuickAssist Technology		Supported	Supported

Random number generation

Device	RNG
STMicroelectronics STM32 F1, F2, F4, L1, W Series (ARM Cortex - M3/M4)	Supported
Cavium NITROX (III/V PX processors)	Supported
Nordic NRF51 (Series SoC family, 32-bit ARM Cortex M0 processor core)	Supported

Licensing

wolfSSL is open source, licensed under the GNU General Public License GPLv2.[15]

See also

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

References

1. "wolfSSL ChangeLog".
2. "wolfSSL ChangeLog". 2020-04-22. Retrieved 2020-04-22.
3. wolfSSL - Embedded Communications Products
4. "What You Need to Know About the TLS 1.3 Protocol and wolfSSL's SSL/TLS Libraries". www.allaboutcircuits.com. Retrieved 2018-12-28.
5. "wolfSSL Embedded SSL/TLS Library | wolfSSL Products". Retrieved 2019-01-31.
6. OpenSSL: Source, License
7. wolfSSL - License
8. MySQL, Building MySQL with Support for Secure Connections
9. wolfSSL - Docs | CyaSSL Manual - Chapter 4 (Features)
10. "wolfSSL 3.6.6 is Now Available".
11. wolfSSL - Docs | wolfSSL Manual - Chapter 10 (wolfCrypt Usage Reference)
12. Kerberos: The Network Authentication Protocol
13. NTRU CryptoLabs Archived 2013-02-02 at Archive.today
14. wolfSSL - wolfSSL with Intel® SGX
15. GNU License

External links

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