# Comparison of TLS implementations

The Transport Layer Security (TLS) protocol provides the ability to secure communications across or inside networks. This comparison of TLS implementations compares several of the most notable libraries. There are several TLS implementations which are free software and open source.
All comparison categories use the stable version of each implementation listed in the overview section. The comparison is limited to features that directly relate to the TLS protocol.

## Overview

| Implementation | Developed by | Open source | Software license | Copyright holder | Written in | Latest stable version, release date | Origin |
| Botan | Jack Lloyd | Yes | Simplified BSD License | Jack Lloyd | C++ | 3.6.1 (October 26, 2024; 4 months ago (2024-10-26)) | US (Vermont) |
| BoringSSL | Google | Yes | OpenSSL-SSLeay dual-license, ISC license | Eric Young, Tim Hudson, Sun, OpenSSL project, Google, and others | C, C++, Go, assembly | ?? | Australia/EU |
| Bouncy Castle | The Legion of the Bouncy Castle Inc. | Yes | MIT License | Legion of the Bouncy Castle Inc. | Java, C# | Java1.80 / January 14, 2025; 2 months ago (2025-01-14)Java LTSBC-LJA 2.73.7 / November 8, 2024; 4 months ago (2024-11-08)Java FIPSBC-FJA 2.0.0 / July 30, 2024; 7 months ago (2024-07-30)C#2.5.1 / February 14, 2025; 32 days ago (2025-02-14)C# FIPSBC-FNA 1.0.2 / March 11, 2024; 12 months ago (2024-03-11) | Australia |
| BSAFE | Dell, formerly RSA Security | No | Proprietary | Dell | Java, C, assembly | SSL-J 6.6 (July 2, 2024; 8 months ago (2024-07-02)) SSL-J 7.3.1 (October 7, 2024; 5 months ago (2024-10-07)) Micro Edition Suite 5.0.3 (December 3, 2024; 3 months ago (2024-12-03)) | Australia |
| cryptlib | Peter Gutmann | Yes | Sleepycat License and commercial license | Peter Gutmann | C | 3.4.5 (2019; 6 years ago (2019)) | NZ |
| GnuTLS | GnuTLS project | Yes | LGPL-2.1-or-later | Free Software Foundation | C | 3.8.9 2025-02-08 | EU (Greece and Sweden) |
| Java Secure Socket Extension (JSSE) | Oracle | Yes | GNU GPLv2 and commercial license | Oracle | Java | 23.0.1 (October 15, 2024; 5 months ago (2024-10-15)) 21.0.5 LTS (October 15, 2024; 5 months ago (2024-10-15)) 17.0.13 LTS (October 15, 2024; 5 months ago (2024-10-15)) 11.0.25 LTS (October 15, 2024; 5 months ago (2024-10-15)) 8u431 LTS (October 15, 2024; 5 months ago (2024-10-15)) | US |
| LibreSSL | OpenBSD Project | Yes | Apache-1.0, BSD-4-Clause, ISC, and public domain | Eric Young, Tim Hudson, Sun, OpenSSL project, OpenBSD Project, and others | C, assembly | 4.0.0 2024-10-14 | Canada |
| MatrixSSL | PeerSec Networks | Yes | GNU GPLv2+ and commercial license | PeerSec Networks | C | 4.2.2 (September 11, 2019; 5 years ago (2019-09-11)) | US |
| Mbed TLS (previously PolarSSL) | Arm | Yes | Apache License 2.0, GNU GPLv2+ and commercial license | Arm Holdings | C | 3.6.2 (15 October 2024; 5 months ago (15 October 2024)) | EU (Netherlands) |
| Network Security Services (NSS) | Mozilla, AOL, Red Hat, Sun, Oracle, Google and others | Yes | MPL 2.0 | NSS contributors | C, assembly | Standard3.84 / October 12, 2022; 2 years ago (2022-10-12)Extended Support Release3.79.1 / August 18, 2022; 2 years ago (2022-08-18) | US |
| OpenSSL | OpenSSL project | Yes | Apache-2.0 | Eric Young, Tim Hudson, Sun, OpenSSL project, and others | C, assembly | 3.4.1 2025-02-11 | Australia/EU |
| Rustls | Joe Birr-Pixton, Dirkjan Ochtman, Daniel McCarney, Josh Aas, and open source contributors | Yes | Apache-2.0, MIT License and ISC | Open source contributors | Rust | v0.23.23 (February 11, 2025; 35 days ago (2025-02-11)) | United Kingdom |
| s2n | Amazon | Yes | Apache License 2.0, GNU GPLv2+ and commercial license | Amazon.com, Inc. | C | Continuous | US |
| Schannel | Microsoft | No | Proprietary | Microsoft Corporation | | Windows 11, 2021-10-05 | US |
| Secure Transport | Apple Inc. | Yes | APSL 2.0 | Apple Inc. | | 57337.20.44 (OS X 10.11.2), 2015-12-08 | US |
| wolfSSL (previously CyaSSL) | wolfSSL | Yes | GNU GPLv2+ and commercial license | wolfSSL Inc. | C, assembly | 5.7.6 (December 31, 2024; 2 months ago (2024-12-31)) | US |
| Erlang/OTP SSL application | Ericsson | Yes | Apache License 2.0 | Ericsson | Erlang | OTP-21, 2018-06-19 | Sweden |
| Implementation | Developed by | Open source | Software license | Copyright owner | Written in | Latest stable version, release date | Origin |
* ↑ Apache-2.0 for OpenSSL 3.0 and later releases. OpenSSL-SSLeay dual-license for any release before OpenSSL 3.0.

## TLS/SSL protocol version support

Several versions of the TLS protocol exist. SSL 2.0 is a deprecated protocol version with significant weaknesses. SSL 3.0 (1996) and TLS 1.0 (1999) are successors with two weaknesses in CBC-padding that were explained in 2001 by Serge Vaudenay. TLS 1.1 (2006) fixed only one of the problems, by switching to random initialization vectors (IV) for CBC block ciphers, whereas the more problematic use of mac-pad-encrypt instead of the secure pad-mac-encrypt was addressed with RFC 7366. A workaround for SSL 3.0 and TLS 1.0, roughly equivalent to random IVs from TLS 1.1, was widely adopted by many implementations in late 2011. In 2014, the POODLE vulnerability of SSL 3.0 was discovered, which takes advantage of the known vulnerabilities in CBC, and an insecure fallback negotiation used in browsers.
TLS 1.2 (2008) introduced a means to identify the hash used for digital signatures. While permitting the use of stronger hash functions for digital signatures in the future (rsa,sha256/sha384/sha512) over the SSL 3.0 conservative choice (rsa,sha1+md5), the TLS 1.2 protocol change inadvertently and substantially weakened the default digital signatures and provides (rsa,sha1) and even (rsa,md5).
Datagram Transport Layer Security (DTLS or Datagram TLS) 1.0 is a modification of TLS 1.1 for a packet-oriented transport layer, where packet loss and packet reordering have to be tolerated. The revision DTLS 1.2 based on TLS 1.2 was published in January 2012.
TLS 1.3 (2018) specified in RFC 8446 includes major optimizations and security improvements. QUIC (2021) specified in RFC 9000 and DTLS 1.3 (2022) specified in RFC 9147 builds on TLS 1.3. The publishing of TLS 1.3 and DTLS 1.3 obsoleted TLS 1.2 and DTLS 1.2.
Note that there are known vulnerabilities in SSL 2.0 and SSL 3.0. In 2021, IETF published RFC 8996 also forbidding negotiation of TLS 1.0, TLS 1.1, and DTLS 1.0 due to known vulnerabilities. NIST SP 800-52 requires support of TLS 1.3 by January 2024. Support of TLS 1.3 means that two compliant nodes will never negotiate TLS 1.2.
| Implementation | SSL 2.0 (insecure) | SSL 3.0 (insecure) | TLS 1.0 (deprecated) | TLS 1.1 (deprecated) | TLS 1.2 | TLS 1.3 | DTLS 1.0 (deprecated) | DTLS 1.2 |
| Botan | No | No | No | No | Yes | Yes | No | Yes |
| BoringSSL | | | Yes | Yes | Yes | Yes | Yes | Yes |
| Bouncy Castle | No | No | Yes | Yes | Yes | Yes (draft version) | Yes | Yes |
| BSAFE SSL-J | No | Disabled by default | No | No | Yes | Yes | No | No |
| cryptlib | No | Disabled by default at compile time | Yes | Yes | Yes | | No | No |
| GnuTLS | No | Disabled by default | Yes | Yes | Yes | Yes | Yes | Yes |
| JSSE | No | Disabled by default | Disabled by default | Disabled by default | Yes | Yes | Yes | Yes |
| LibreSSL | No | No | Yes | Yes | Yes | Yes | Yes | Yes |
| MatrixSSL | No | Disabled by default at compile time | Yes | Yes | Yes | Yes | Yes | Yes |
| Mbed TLS | No | No | No | No | Yes | Yes (experimental) | Yes | Yes |
| NSS | No | Disabled by default | Yes | Yes | Yes | Yes | Yes | Yes |
| OpenSSL | No | Disabled by default | Yes | Yes | Yes | Yes | Yes | Yes |
| Rustls | No | No | No | No | Yes | Yes | No | No |
| s2n | No | Disabled by default | Yes | Yes | Yes | Yes | No | No |
| Schannel XP, 2003 | Disabled by default in MSIE 7 | Enabled by default | Enabled by default in MSIE 7 | No | No | No | No | No |
| Schannel Vista | Disabled by default | Enabled by default | Yes | No | No | No | No | No |
| Schannel 2008 | Disabled by default | Enabled by default | Yes | Disabled by default (KB4019276) | Disabled by default (KB4019276) | No | No | No |
| Schannel 7, 2008R2 | Disabled by default | Disabled by default in MSIE 11 | Yes | Enabled by default in MSIE 11 | Enabled by default in MSIE 11 | No | Yes | No |
| Schannel 8, 2012 | Disabled by default | Enabled by default | Yes | Disabled by default | Disabled by default | No | Yes | No |
| Schannel 8.1, 2012R2, 10 RTM & v1511 | Disabled by default | Disabled by default in MSIE 11 | Yes | Yes | Yes | No | Yes | No |
| Schannel 10 v1607 / 2016 | No | Disabled by default | Yes | Yes | Yes | No | Yes | Yes |
| Schannel 11 / 2022 | No | Disabled by default | Yes | Yes | Yes | Yes | Yes | Yes |
| Secure Transport OS X 10.2-10.7, iOS 1-4 | Yes | Yes | Yes | No | No | | No | No |
| Secure Transport OS X 10.8-10.10, iOS 5-8 | No | Yes | Yes | Yes | Yes | | Yes | No |
| Secure Transport OS X 10.11, iOS 9 | No | No | Yes | Yes | Yes | | Yes | Un­known |
| Secure Transport OS X 10.13, iOS 11 | No | No | Yes | Yes | Yes | Yes (draft version) | Yes | Un­known |
| wolfSSL | No | Disabled by default | Disabled by default | Yes | Yes | Yes | Yes | Yes |
| Erlang/OTP SSL application | No | No | Disabled by default | Disabled by default | Yes | Partially | Disabled by default | Yes |
| Implementation | SSL 2.0 (insecure) | SSL 3.0 (insecure) | TLS 1.0 (deprecated) | TLS 1.1 (deprecated) | TLS 1.2 | TLS 1.3 | DTLS 1.0 (deprecated) | DTLS 1.2 |
* 1 2 As of SSL-J 7.0, support for TLS 1.0 and 1.1 has been removed
* 1 2 SSL 2.0 client hello is supported for backward compatibility reasons even though SSL 2.0 is not supported.
* ↑ Server-side implementation of the SSL/TLS protocol still supports processing of received v2-compatible client hello messages."NSS 3.24 release notes". Mozilla Developer Network. Mozilla. Archived from the original on 2016-08-26. Retrieved 2016-06-19.
* 1 2 3 4 5 6 Secure Transport: SSL 2.0 was discontinued in OS X 10.8. SSL 3.0 was discontinued in OS X 10.11 and iOS 9.TLS 1.1, 1.2 and DTLS are available on iOS 5.0 and later, and OS X 10.9 and later."Technical Note TN2287: iOS 5 and TLS 1.2 Interoperability Issues". iOS Developer Library. Apple Inc. Retrieved 2012-05-03.
* 1 2 3 4 Since OTP 22
* ↑ Since OTP 23
* ↑ "Erlang OTP SSL application TLS 1.3 compliance table".

## NSA Suite B Cryptography

Required components for NSA Suite B Cryptography (RFC 6460) are:
* Advanced Encryption Standard (AES) with key sizes of 128 and 256 bits. For traffic flow, AES should be used with either the Counter Mode (CTR) for low bandwidth traffic or the Galois/Counter Mode (GCM) mode of operation for high bandwidth traffic (see Block cipher modes of operation) — symmetric encryption
* Elliptic Curve Digital Signature Algorithm (ECDSA) — digital signatures
* Elliptic Curve Diffie–Hellman (ECDH) — key agreement
* Secure Hash Algorithm 2 (SHA-256 and SHA-384) — message digest
Per CNSSP-15, the 256-bit elliptic curve (specified in FIPS 186-2), SHA-256, and AES with 128-bit keys are sufficient for protecting classified information up to the Secret level, while the 384-bit elliptic curve (specified in FIPS 186-2), SHA-384, and AES with 256-bit keys are necessary for the protection of Top Secret information.
| Implementation | TLS 1.2 Suite B |
| Botan | Yes |
| Bouncy Castle | Yes |
| BSAFE | Yes |
| cryptlib | Yes |
| GnuTLS | Yes |
| JSSE | Yes |
| LibreSSL | Yes |
| MatrixSSL | Yes |
| Mbed TLS | Yes |
| NSS | No |
| OpenSSL | Yes |
| Rustls | Yes |
| S2n | |
| Schannel | Yes |
| Secure Transport | No |
| wolfSSL | Yes |
| Implementation | TLS 1.2 Suite B |

## Certifications

Note that certain certifications have received serious negative criticism from people who are actually involved in them.
| Implementation | FIPS 140-1, FIPS 140-2 | FIPS 140-1, FIPS 140-2 | FIPS 140-3 |
| Implementation | Level 1 | Level 2 | Level 1 |
| Botan | | | |
| Bouncy Castle | BC-FJA 1.0.0 (#2768) BC-FJA 1.0.1 (#3152) | | |
| BSAFE SSL-J | Crypto-J 6.0 (1785, 1786) Crypto-J 6.1 / 6.1.1.0.1 (2057, 2058) Crypto-J 6.2 / 6.2.1.1 (2468, 2469) Crypto-J 6.2.4 (3172, 3184) Crypto-J 6.2.5 (#3819, #3820) Crypto-J 6.3 (#4696, #4697) | | Crypto-J 7.0 (4892) |
| cryptlib | | | |
| GnuTLS | Red Hat Enterprise Linux GnuTLS Cryptographic Module (#2780) | | |
| JSSE | | | |
| LibreSSL | no support | | |
| MatrixSSL | SafeZone FIPS Cryptographic Module: 1.1 (#2389) | | |
| Mbed TLS | | | |
| NSS | Network Security Services: 3.2.2 (#247) Network Security Services Cryptographic Module: 3.11.4 (#815), 3.12.4 (#1278), 3.12.9.1 (#1837) | Netscape Security Module: 1 (#7), 1.01 (#47) Network Security Services: 3.2.2 (#248) Network Security Services Cryptographic Module: 3.11.4 (#814), 3.12.4 (#1279, #1280) | |
| OpenSSL | OpenSSL FIPS Object Module: 1.0 (#624), 1.1.1 (#733), 1.1.2 (#918), 1.2, 1.2.1, 1.2.2, 1.2.3 or 1.2.4 (#1051) 2.0, 2.0.1, 2.0.2, 2.0.3, 2.0.4, 2.0.5, 2.0.6, 2.0.7 or 2.0.8 (#1747) | | |
| Rustls | | | aws-lc FIPS module (#4759) |
| Schannel | Cryptographic modules in Windows NT 4.0, 95, 95, 2000, XP, Server 2003, CE 5, CE 6, Mobile 6.x, Vista, Server 2008, 7, Server 2008 R2, 8, Server 2012, RT, Surface, Phone 8 See details on Microsoft FIPS 140 Validated Cryptographic Modules | | |
| Secure Transport | Apple FIPS Cryptographic Module: 1.0 (OS X 10.6, #1514), 1.1 (OS X 10.7, #1701) Apple OS X CoreCrypto Module; CoreCrypto Kernel Module: 3.0 (OS X 10.8, #1964, #1956), 4.0 (OS X 10.9, #2015, #2016) Apple iOS CoreCrypto Module; CoreCrypto Kernel Module: 3.0 (iOS 6, #1963, #1944), 4.0 (iOS 7, #2020, #2021) | | |
| wolfSSL | wolfCrypt FIPS Module: 4.0 (#3389) See details on NIST certificate for validated Operating Environments wolfCrypt FIPS Module: 3.6.0 (#2425) See details on NIST certificate for validated Operating Environments | | wolfCrypt FIPS Module (#4178) See details on NIST certificate |
| Implementation | Level 1 | Level 2 | Level 1 |
| Implementation | FIPS 140-1, FIPS 140-2 | FIPS 140-1, FIPS 140-2 | FIPS 140-3 |
* ↑ with Sun Sparc 5 w/ Sun Solaris v 2.4SE (ITSEC-rated)
* ↑ with Sun Ultra-5 w/ Sun Trusted Solaris version 2.5.1 (ITSEC-rated)
* ↑ with Solaris v8.0 with AdminSuite 3.0.1 as specified in UK IT SEC CC Report No. P148 EAL4 on a SUN SPARC Ultra-1
* ↑ with these platforms; Red Hat Enterprise Linux Version 4 Update 1 AS on IBM xSeries 336 with Intel Xeon CPU, Trusted Solaris 8 4/01 on Sun Blade 2500 Workstation with UltraSPARC IIIi CPU
* ↑ with these platforms; Red Hat Enterprise Linux v5 running on an IBM System x3550, Red Hat Enterprise Linux v5 running on an HP ProLiant DL145, Sun Solaris 10 5/08 running on a Sun SunBlade 2000 workstation, Sun Solaris 10 5/08 running on a Sun W2100z workstation

## Key exchange algorithms (certificate-only)

This section lists the certificate verification functionality available in the various implementations.
| Implementation | RSA | RSA-EXPORT (insecure) | DHE-RSA (forward secrecy) | DHE-DSS (forward secrecy) | ECDH-ECDSA | ECDHE-ECDSA (forward secrecy) | ECDH-RSA | ECDHE-RSA (forward secrecy) | GOST R 34.10-94, 34.10-2001 |
| Botan | Disabled by default | No | Yes | Disabled by default | No | Yes | No | Yes | No |
| BSAFE | Yes | No | Yes | Yes | Yes | Yes | Yes | Yes | No |
| cryptlib | Yes | No | Yes | Yes | No | Yes | No | No | No |
| GnuTLS | Yes | No | Yes | Disabled by default | No | Yes | No | Yes | No |
| JSSE | Yes | Disabled by default | Yes | Yes | Yes | Yes | Yes | Yes | No |
| LibreSSL | Yes | No | Yes | Yes | No | Yes | No | Yes | Yes |
| MatrixSSL | Yes | No | Yes | No | Yes | Yes | Yes | Yes | No |
| Mbed TLS | Yes | No | Yes | No | Yes | Yes | Yes | Yes | No |
| NSS | Yes | Disabled by default | Yes | Yes | Yes | Yes | Yes | Yes | No |
| OpenSSL | Yes | No | Yes | Disabled by default | No | Yes | No | Yes | Yes |
| Rustls | No | No | No | No | No | Yes | No | Yes | No |
| Schannel XP/2003 | Yes | Yes | No | XP: Max 1024 bits 2003: 1024 bits only | No | No | No | No | No |
| Schannel Vista/2008 | Yes | Disabled by default | No | 1024 bits by default | No | Yes | No | except AES_GCM | No |
| Schannel 8/2012 | Yes | Disabled by default | AES_GCM only | 1024 bits by default | No | Yes | No | except AES_GCM | No |
| Schannel 7/2008R2, 8.1/2012R2 | Yes | Disabled by default | Yes | 2048 bits by default | No | Yes | No | except AES_GCM | No |
| Schannel 10 | Yes | Disabled by default | Yes | 2048 bits by default | No | Yes | No | Yes | No |
| Secure Transport OS X 10.6 | Yes | Yes | except AES_GCM | Yes | Yes | except AES_GCM | yes | except AES_GCM | No |
| Secure Transport OS X 10.8-10.10 | Yes | No | except AES_GCM | No | Yes | except AES_GCM | Yes | except AES_GCM | No |
| Secure Transport OS X 10.11 | Yes | No | Yes | No | No | Yes | No | Yes | No |
| wolfSSL | Yes | No | Yes | No | Yes | Yes | Yes | Yes | No |
| Erlang/OTP SSL application | Yes | No | Yes | Yes | Yes | Yes | Yes | Yes | No |
| Implementation | RSA | RSA-EXPORT (insecure) | DHE-RSA (forward secrecy) | DHE-DSS (forward secrecy) | ECDH-ECDSA | ECDHE-ECDSA (forward secrecy) | ECDH-RSA | ECDHE-RSA (forward secrecy) | GOST R 34.10-94, 34.10-2001 |

## Key exchange algorithms (alternative key-exchanges)

| Implementation | SRP | SRP-DSS | SRP-RSA | PSK-RSA | PSK | DHE-PSK (forward secrecy) | ECDHE-PSK (forward secrecy) | KRB5 | DH-ANON (insecure) | ECDH-ANON (insecure) |
| Botan | No | No | No | No | Yes | No | Yes | No | No | No |
| BSAFE SSL-J | No | No | No | No | Yes | No | No | No | Disabled by default | Disabled by default |
| cryptlib | No | No | No | No | Yes | Yes | No | Un­known | No | No |
| GnuTLS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Disabled by default | Disabled by default |
| JSSE | No | No | No | No | No | No | No | No | Disabled by default | Disabled by default |
| LibreSSL | No | No | No | No | No | No | No | No | Yes | Yes |
| MatrixSSL | No | No | No | Yes | Yes | Yes | No | No | Disabled by default | No |
| Mbed TLS | No | No | No | Yes | Yes | Yes | Yes | No | No | No |
| NSS | No | No | No | No | No | No | No | No | Client side only, disabled by default | Disabled by default |
| OpenSSL | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Disabled by default | Disabled by default |
| Rustls | No | No | No | No | No | No | No | No | No | No |
| Schannel | No | No | No | No | No | No | No | Yes | No | No |
| Secure Transport | No | No | No | No | No | No | No | Un­known | Yes | Yes |
| wolfSSL | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No |
| Erlang/OTP SSL application | Disabled by default | Disabled by default | Disabled by default | Disabled by default | Disabled by default | Disabled by default | No | No | Disabled by default | Disabled by default |
| Implementation | SRP | SRP-DSS | SRP-RSA | PSK-RSA | PSK | DHE-PSK (forward secrecy) | ECDHE-PSK (forward secrecy) | KRB5 | DH-ANON (insecure) | ECDH-ANON (insecure) |

## Certificate verification methods

| Implementation | Application-defined | PKIX path validation | CRL | OCSP | DANE (DNSSEC) | CT |
| Botan | Yes | Yes | Yes | Yes | No | Un­known |
| Bouncy Castle | Yes | Yes | Yes | Yes | Yes | Un­known |
| BSAFE | Yes | Yes | Yes | Yes | No | Un­known |
| cryptlib | Yes | Yes | Yes | Yes | No | Un­known |
| GnuTLS | Yes | Yes | Yes | Yes | Yes | Un­known |
| JSSE | Yes | Yes | Yes | Yes | No | No |
| LibreSSL | Yes | Yes | Yes | Yes | No | Un­known |
| MatrixSSL | Yes | Yes | Yes | Yes | No | Un­known |
| Mbed TLS | Yes | Yes | Yes | No | No | Un­known |
| NSS | Yes | Yes | Yes | Yes | No | Un­known |
| OpenSSL | Yes | Yes | Yes | Yes | Yes | Yes |
| Rustls | Yes | Yes | Yes | No | No | No |
| s2n | | | No | Un­known | | Un­known |
| Schannel | Un­known | Yes | Yes | Yes | No | Un­known |
| Secure Transport | Yes | Yes | Yes | Yes | No | Un­known |
| wolfSSL | Yes | Yes | Yes | Yes | No | Un­known |
| Erlang/OTP SSL application | Yes | Yes | Yes | No | No | Un­known |
| Implementation | Application-defined | PKIX path validation | CRL | OCSP | DANE (DNSSEC) | CT |

## Encryption algorithms

| Implementation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Stream cipher | None |
| Implementation | AES GCM | AES CCM | AES CBC | Camellia GCM | Camellia CBC | ARIA GCM | ARIA CBC | SEED CBC | 3DES EDE CBC (insecure) | GOST 28147-89 CNT (proposed) | ChaCha20-Poly1305 | Null (insecure) |
| Botan | Yes | Yes | Yes | Yes | Yes | No | No | Disabled by default | Disabled by default | No | Yes | Not implemented |
| BoringSSL | Yes | No | Yes | No | No | No | No | No | Yes | No | Yes | |
| BSAFE SSL-J | Yes | Yes | Yes | No | No | No | No | No | Disabled by default | No | No | Disabled by default |
| cryptlib | Yes | No | Yes | No | No | No | No | No | Yes | No | No | Not implemented |
| GnuTLS | Yes | Yes | Yes | Yes | Yes | No | No | No | Disabled by default | No | Yes | Disabled by default |
| JSSE | Yes | No | Yes | No | No | No | No | No | Disabled by default | No | Yes (JDK 12+) | Disabled by default |
| LibreSSL | Yes | No | Yes | No | Yes | No | No | No | Yes | Yes | Yes | Disabled by default |
| MatrixSSL | Yes | No | Yes | No | No | No | No | Yes | Disabled by default | No | Yes | Disabled by default |
| Mbed TLS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No | Yes | Disabled by default at compile time |
| NSS | Yes | No | Yes | No | Yes | No | No | Yes | Yes | No | Yes | Disabled by default |
| OpenSSL | Yes | Disabled by default | Yes | No | Disabled by default | Disabled by default | No | Disabled by default | Disabled by default | Yes | Yes | Disabled by default |
| Rustls | Yes | No | No | No | No | No | No | No | No | No | Yes | Not implemented |
| Schannel XP/2003 | No | No | 2003 only | No | No | No | No | No | Yes | No | No | Disabled by default |
| Schannel Vista/2008, 2008R2, 2012 | No | No | Yes | No | No | No | No | No | Yes | No | No | Disabled by default |
| Schannel 7, 8, 8.1/2012R2 | Yes except ECDHE_RSA | No | Yes | No | No | No | No | No | Yes | No | No | Disabled by default |
| Schannel 10 | Yes | No | Yes | No | No | No | No | No | Yes | No | No | Disabled by default |
| Secure Transport OS X 10.6 - 10.10 | No | No | Yes | No | No | No | No | No | Yes | No | No | Disabled by default |
| Secure Transport OS X 10.11 | Yes | No | Yes | No | No | No | No | No | Yes | No | No | Disabled by default |
| wolfSSL | Yes | Yes | Yes | No | No | No | No | No | Yes | No | Yes | Disabled by default |
| Erlang/OTP SSL application | Yes | No | Yes | No | No | No | No | No | Disabled by default | No | Experimental | Disable by default |
| Implementation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Stream cipher | None |
| Implementation | AES GCM | AES CCM | AES CBC | Camellia GCM | Camellia CBC | ARIA GCM | ARIA CBC | SEED CBC | 3DES EDE CBC (insecure) | GOST 28147-89 CNT (proposed) | ChaCha20-Poly1305 | Null (insecure) |

### Notes

* 1 2 This algorithm is not defined yet as TLS cipher suites in RFCs, is proposed in drafts.
* 1 2 authentication only, no encryption
* ↑ This algorithm is implemented in an NSS fork used by Pale Moon.

### Obsolete algorithms

| Implementation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Stream cipher | Stream cipher |
| Implementation | IDEA CBC(insecure) | DES CBC (insecure) | DES-40 CBC (EXPORT, insecure) | RC2-40 CBC (EXPORT, insecure) | RC4-128 (insecure) | RC4-40 (EXPORT, insecure) |
| Botan | No | No | No | No | No | No |
| BoringSSL | No | No | No | No | Disabled by default at compile time | No |
| BSAFE SSL-J | No | Disabled by default | Disabled by default | No | Disabled by default | Disabled by default |
| cryptlib | No | Disabled by default at compile time | No | No | Disabled by default at compile time | No |
| GnuTLS | No | No | No | No | Disabled by default | No |
| JSSE | No | Disabled by default | Disabled by default | No | Disabled by default | Disabled by default |
| LibreSSL | Yes | Yes | No | No | Yes | No |
| MatrixSSL | Yes | No | No | No | Disabled by default | No |
| Mbed TLS | No | Disabled by default at compile time | No | No | Disabled by default at compile time | No |
| NSS | Yes | Disabled by default | Disabled by default | Disabled by default | Lowest priority | Disabled by default |
| OpenSSL | Disabled by default | Disabled by default | No | No | Disabled by default | No |
| Rustls | No | No | No | No | No | No |
| Schannel XP/2003 | No | Yes | Yes | Yes | Yes | Yes |
| Schannel Vista/2008 | No | Disabled by default | Disabled by default | Disabled by default | Yes | Disabled by default |
| Schannel 7/2008R2 | No | Disabled by default | Disabled by default | Disabled by default | Lowest priority will be disabled soon | Disabled by default |
| Schannel 8/2012 | No | Disabled by default | Disabled by default | Disabled by default | Only as fallback | Disabled by default |
| Schannel 8.1/2012R2 | No | Disabled by default | Disabled by default | Disabled by default | Disabled by default | Disabled by default |
| Schannel 10 | No | Disabled by default | Disabled by default | Disabled by default | Disabled by default | Disabled by default |
| Secure Transport OS X 10.6 | Yes | Yes | Yes | Yes | Yes | Yes |
| Secure Transport OS X 10.7 | Yes | Un­known | Un­known | Un­known | Yes | Un­known |
| Secure Transport OS X 10.8-10.9 | Yes | Disabled by default | Disabled by default | Disabled by default | Yes | Disabled by default |
| Secure Transport OS X 10.10-10.11 | Yes | Disabled by default | Disabled by default | Disabled by default | Lowest priority | Disabled by default |
| Secure Transport macOS 10.12 | Yes | Disabled by default | Disabled by default | Disabled by default | Disabled by default | Disabled by default |
| wolfSSL | Disabled by default | No | No | No | Disabled by default | No |
| Erlang/OTP SSL application | no | Disabled by default | no | no | Disabled by default | no |
| Implementation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Block cipher with mode of operation | Stream cipher | Stream cipher |
| Implementation | IDEA CBC(insecure) | DES CBC (insecure) | DES-40 CBC (EXPORT, insecure) | RC2-40 CBC (EXPORT, insecure) | RC4-128 (insecure) | RC4-40 (EXPORT, insecure) |

#### Notes

* 1 2 3 4 IDEA and DES have been removed from TLS 1.2.
* 1 2 3 4 5 6 40 bits strength of cipher suites were designed to operate at reduced key lengths in order to comply with US regulations about the export of cryptographic software containing certain strong encryption algorithms (see Export of cryptography from the United States). These weak suites are forbidden in TLS 1.1 and later.
* 1 2 The RC4 attacks weaken or break RC4 used in SSL/TLS. Use of RC4 is prohibited by RFC 7465.
* 1 2 The RC4 attacks weaken or break RC4 used in SSL/TLS.

## Supported elliptic curves

This section lists the supported elliptic curves by each implementation.

### Defined curves in RFC 8446 (for TLS 1.3) and RFC 8422, 7027 (for TLS 1.2 and earlier)

| applicable TLS version | TLS 1.3 and earlier | TLS 1.3 and earlier | TLS 1.3 and earlier | TLS 1.3 and earlier | TLS 1.3 and earlier | TLS 1.2 and earlier | TLS 1.2 and earlier | TLS 1.2 and earlier |
| Implementation | secp256r1 prime256v1 NIST P-256 (0x0017, 23) | secp384r1 NIST P-384 (0x0018, 24) | secp521r1 NIST P-521 (0x0019, 25) | X25519 (0x001D, 29) | X448 (0x001E, 30) | brainpoolP256r1 (26) | brainpoolP384r1 (27) | brainpoolP512r1 (28) |
| Botan | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes |
| BoringSSL | Yes | Yes | Yes (disabled by default) | Yes | No | No | No | No |
| BSAFE | Yes | Yes | Yes | No | No | No | No | No |
| GnuTLS | Yes | Yes | Yes | Yes | Yes | No | No | No |
| JSSE | Yes | Yes | Yes | Yes x25519: JDK 13+ Ed25519:JDK 15+ | Yes x448: JDK 13+ Ed448: JDK 15+ | No | No | No |
| LibreSSL | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes |
| MatrixSSL | Yes | Yes | Yes | TLS 1.3 only | No | Yes | Yes | Yes |
| Mbed TLS | Yes | Yes | Yes | Primitive only | Primitive only | Yes | Yes | Yes |
| NSS | Yes | Yes | Yes | Yes | No | No | No | No |
| OpenSSL | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Rustls | Yes | Yes | No | Yes | No | No | No | No |
| Schannel Vista/2008, 7/2008R2, 8/2012, 8.1/2012R2, 10 | Yes | Yes | Yes | No | No | No | No | No |
| Secure Transport | Yes | Yes | Yes | No | No | No | No | No |
| wolfSSL | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Erlang/OTP SSL application | Yes | Yes | Yes | No | No | Yes | Yes | Yes |
| Implementation | secp256r1 prime256v1 NIST P-256 (0x0017, 23) | secp384r1 NIST P-384 (0x0018, 24) | secp521r1 NIST P-521 (0x0019, 25) | X25519 (0x001D, 29) | X448 (0x001E, 30) | brainpoolP256r1 (26) | brainpoolP384r1 (27) | brainpoolP512r1 (28) |

### Deprecated curves in RFC 8422

| Implementation | sect163k1 NIST K-163 (1) | sect163r1 (2) | sect163r2 NIST B-163 (3) | sect193r1 (4) | sect193r2 (5) | sect233k1 NIST K-233 (6) | sect233r1 NIST B-233 (7) | sect239k1 (8) | sect283k1 NIST K-283 (9) | sect283r1 NIST B-283 (10) | sect409k1 NIST K-409 (11) | sect409r1 NIST B-409 (12) | sect571k1 NIST K-571 (13) | sect571r1 NIST B-571 (14) |
| Botan | No | No | No | No | No | No | No | No | No | No | No | No | No | No |
| BoringSSL | No | No | No | No | No | No | No | No | No | No | No | No | No | No |
| BSAFE | Yes | No | Yes | No | No | Yes | Yes | No | Yes | Yes | Yes | Yes | Yes | Yes |
| GnuTLS | No | No | No | No | No | No | No | No | No | No | No | No | No | No |
| JSSE | Notes | Notes | Notes | Notes | Notes | Notes | Notes | Notes | Notes | Notes | Notes | Notes | Notes | Notes |
| LibreSSL | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| MatrixSSL | No | No | No | No | No | No | No | No | No | No | No | No | No | No |
| Mbed TLS | No | No | No | No | No | No | No | No | No | No | No | No | No | No |
| NSS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| OpenSSL | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Rustls | No | No | No | No | No | No | No | No | No | No | No | No | No | No |
| Schannel Vista/2008, 7/2008R2, 8/2012, 8.1/2012R2, 10 | No | No | No | No | No | No | No | No | No | No | No | No | No | No |
| Secure Transport | No | No | No | No | No | No | No | No | No | No | No | No | No | No |
| wolfSSL | No | No | No | No | No | No | No | No | No | No | No | No | No | No |
| Erlang/OTP SSL application | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Implementation | sect163k1 NIST K-163 (1) | sect163r1 (2) | sect163r2 NIST B-163 (3) | sect193r1 (4) | sect193r2 (5) | sect233k1 NIST K-233 (6) | sect233r1 NIST B-233 (7) | sect239k1 (8) | sect283k1 NIST K-283 (9) | sect283r1 NIST B-283 (10) | sect409k1 NIST K-409 (11) | sect409r1 NIST B-409 (12) | sect571k1 NIST K-571 (13) | sect571r1 NIST B-571 (14) |
| Implementation | secp160k1 (15) | secp160r1 (16) | secp160r2 (17) | secp192k1 (18) | secp192r1 prime192v1 NIST P-192 (19) | secp224k1 (20) | secp224r1 NIST P-244 (21) | secp256k1 (22) | arbitrary prime curves (0xFF01) | arbitrary char2 curves (0xFF02) |
| Botan | No | No | No | No | No | No | No | No | No | No |
| BoringSSL | No | No | No | No | No | No | Yes | No | No | No |
| BSAFE | No | No | No | No | Yes | No | Yes | No | No | No |
| GnuTLS | No | No | No | No | Yes | No | Yes | No | No | No |
| JSSE | Notes | Notes | Notes | Notes | Notes | Notes | Notes | Notes | No | No |
| LibreSSL | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No |
| MatrixSSL | No | No | No | No | Yes | No | Yes | No | No | No |
| Mbed TLS | No | No | No | Yes | Yes | Yes | Yes | Yes | No | No |
| NSS | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No |
| OpenSSL | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No |
| Rustls | No | No | No | No | No | No | No | No | No | No |
| Schannel Vista/2008, 7/2008R2, 8/2012, 8.1/2012R2, 10 | No | No | No | No | No | No | No | No | No | No |
| Secure Transport | No | No | No | No | Yes | No | No | No | No | No |
| wolfSSL | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No |
| Erlang/OTP SSL application | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No |
| Implementation | secp160k1 (15) | secp160r1 (16) | secp160r2 (17) | secp192k1 (18) | secp192r1 prime192v1 NIST P-192 (19) | secp224k1 (20) | secp224r1 NIST P-244 (21) | secp256k1 (22) | arbitrary prime curves (0xFF01) | arbitrary char2 curves (0xFF02) |

#### Notes

* 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 These elliptic curves were "Disabled by Default" in current JDK families as part of JDK-8236730.
* 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 These elliptic curves were subsequently removed in JDK 16+ as part of JDK-8252601.

## Data integrity

| Implementation | HMAC-MD5 | HMAC-SHA1 | HMAC-SHA256/384 | AEAD | GOST 28147-89 IMIT | GOST R 34.11-94 |
| Botan | No | Yes | Yes | Yes | No | No |
| BSAFE | Yes | Yes | Yes | Yes | No | No |
| cryptlib | Yes | Yes | Yes | Yes | No | No |
| GnuTLS | Yes | Yes | Yes | Yes | No | No |
| JSSE | Disabled by Default | Yes | Yes | Yes | No | No |
| LibreSSL | Yes | Yes | Yes | Yes | Yes | Yes |
| MatrixSSL | Yes | Yes | Yes | Yes | No | No |
| Mbed TLS | Yes | Yes | Yes | Yes | No | No |
| NSS | Yes | Yes | Yes | Yes | No | No |
| OpenSSL | Yes | Yes | Yes | Yes | Yes | Yes |
| Rustls | No | No | No | Yes | No | No |
| Schannel XP/2003, Vista/2008 | Yes | Yes | XP SP3, 2003 SP2 via hotfix | No | No | No |
| Schannel 7/2008R2, 8/2012, 8.1/2012R2 | Yes | Yes | Yes | except ECDHE_RSA | No | No |
| Schannel 10 | Yes | Yes | Yes | Yes | No | No |
| Secure Transport | Yes | Yes | Yes | Yes | No | No |
| wolfSSL | Yes | Yes | Yes | Yes | No | No |
| Erlang/OTP SSL application | Yes | Yes | Yes | Yes | No | No |
| Implementation | HMAC-MD5 | HMAC-SHA1 | HMAC-SHA256/384 | AEAD | GOST 28147-89 IMIT | GOST R 34.11-94 |

## Compression

Note the CRIME security exploit takes advantage of TLS compression, so conservative implementations do not enable compression at the TLS level. HTTP compression is unrelated and unaffected by this exploit, but is exploited by the related BREACH attack.
| Implementation | DEFLATE (insecure) |
| Botan | No |
| BSAFE | No |
| cryptlib | No |
| GnuTLS | Disabled by default |
| JSSE | No |
| LibreSSL | No |
| MatrixSSL | Disabled by default |
| Mbed TLS | Disabled by default |
| NSS | Disabled by default |
| OpenSSL | Disabled by default |
| Rustls | No |
| Schannel | No |
| Secure Transport | No |
| wolfSSL | Disabled by default |
| Erlang/OTP SSL application | No |
| Implementation | DEFLATE |

## Extensions

In this section the extensions each implementation supports are listed. Note that the Secure Renegotiation extension is critical for HTTPS client security. TLS clients not implementing it are vulnerable to attacks, irrespective of whether the client implements TLS renegotiation.
| Implementation | Secure Renegotiation | Server Name Indication | ALPN | Certificate Status Request | OpenPGP | Supplemental Data | Session Ticket | Keying Material Exporter | Maximum Fragment Length | Encrypt-then-MAC | TLS Fallback SCSV | Extended Master Secret | ClientHello Padding | Raw Public Keys |
| Botan | Yes | Yes | Yes | No | No | No | Yes | Yes | Yes | Yes | Yes | Yes | No | Un­known |
| BSAFE SSL-J | Yes | Yes | No | Yes | No | No | No | No | Yes | No | No | Yes | No | No |
| cryptlib | Yes | Yes | No | No | No | Yes | No | No | No | Yes | Yes | Yes | No | Un­known |
| GnuTLS | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| JSSE | Yes | Yes | Yes | Yes | No | No | Yes | No | Yes | No | No | Yes | No | No |
| LibreSSL | Yes | Yes | Yes | Yes | No | No? | Yes | Yes? | No | No | Server side only | No | Yes | No |
| MatrixSSL | Yes | Yes | Yes | Yes | No | No | Yes | No | Yes | No | Yes | Yes | No | Un­known |
| Mbed TLS | Yes | Yes | Yes | No | No | No | Yes | No | Yes | Yes | Yes | Yes | No | No |
| NSS | Yes | Yes | Yes | Yes | No | No | Yes | Yes | No | No | Yes | Yes | Yes | Un­known |
| OpenSSL | Yes | Yes | Yes | Yes | No | No? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Rustls | Yes | Yes | Yes | Yes | No | No | Yes | Yes | No | No | No | Yes | No | Un­known |
| Schannel XP/2003 | No | No | No | No | No | Yes | No | No | No | No | No | No | No | Un­known |
| Schannel Vista/2008 | Yes | Yes | No | No | No | Yes | No | No | No | No | No | Yes | No | Un­known |
| Schannel 7/2008R2 | Yes | Yes | No | Yes | No | Yes | No | No | No | No | No | Yes | No | Un­known |
| Schannel 8/2012 | Yes | Yes | No | Yes | No | Yes | Client side only | No | No | No | No | Yes | No | Un­known |
| Schannel 8.1/2012R2, 10 | Yes | Yes | Yes | Yes | No | Yes | Yes | No | No | No | No | Yes | No | Un­known |
| Secure Transport | Yes | Yes | Un­known | No | No | Yes | No | No | No | No | No | No | No | Un­known |
| wolfSSL | Yes | Yes | Yes | Yes | No | No | Yes | No | Yes | Yes | No | Yes | No | Yes |
| Erlang/OTP SSL application | Yes | Yes | Yes | No | No | No | No | No | No | No | Yes | No | No | Un­known |
| Implementation | Secure Renegotiation | Server Name Indication | ALPN | Certificate Status Request | OpenPGP | Supplemental Data | Session Ticket | Keying Material Exporter | Maximum Fragment Length | Encrypt-then-MAC | TLS Fallback SCSV | Extended Master Secret | ClientHello Padding | Raw Public Keys |

## Assisted cryptography

This section lists the known ability of an implementation to take advantage of CPU instruction sets that optimize encryption, or utilize system specific devices that allow access to underlying cryptographic hardware for acceleration or for data separation.
| Implementation | PKCS #11 device | Intel AES-NI | VIA PadLock | ARMv8-A | Intel SHA | NXP CAAM | TPM 2.0 | NXP SE050 | Microchip ATECC | STMicro STSAFE | Maxim MAXQ |
| Botan | Yes | Yes | No | Yes | | No | Yes | No | No | No | No |
| BSAFE SSL-J | Yes | Yes | No | Yes | Yes | No | No | No | No | No | No |
| cryptlib | Yes | Yes | Yes | No | | | | No | No | No | No |
| Crypto++ | | Yes | | | Yes | | | No | No | No | No |
| GnuTLS | Yes | Yes | Yes | Yes | Yes | | No | No | No | No | No |
| JSSE | Yes | Yes | No | No | | No | | No | No | No | No |
| LibreSSL | No | Yes | Yes | No | | | | No | No | No | No |
| MatrixSSL | Yes | Yes | No | Yes | | No | | No | No | No | No |
| Mbed TLS | Yes | Yes | Yes | No | | No | | Partial | Yes | No | No |
| NSS | Yes | Yes | No | No | | No | | No | No | No | No |
| OpenSSL | Yes | Yes | Yes | Yes | Yes | Partial | Partial | Partial | No | Partial | No |
| Rustls | | Yes | | Yes | Yes | | | No | No | No | No |
| Schannel | No | Yes | No | No | | No | | No | No | No | No |
| Secure Transport | No | Yes | No | Yes | | No | | No | No | No | No |
| wolfSSL | Yes | Yes | No | Yes | | Yes | Yes | Yes | Yes | Yes | Yes |
| Implementation | PKCS #11 device | Intel AES-NI | VIA PadLock | ARMv8-A | Intel SHA | NXP CAAM | TPM 2.0 | NXP SE050 | Microchip ATECC | STMicro STSAFE | Maxim MAXQ |
* ↑ Pure Java implementations relies on JVM processor optimization capabilities, such as OpenJDK support for AES-NI
* ↑ BSAFE SSL-J can be configured to run in native mode, using BSAFE Crypto-C Micro Edition to benefit from processor optimization.

## System-specific backends

This section lists the ability of an implementation to take advantage of the available operating system specific backends, or even the backends provided by another implementation.
| Implementation | /dev/crypto | af_alg | Windows CSP | CommonCrypto | OpenSSL engine |
| Botan | No | No | No | No | Partial |
| BSAFE | No | No | No | No | No |
| cryptlib | No | No | No | No | No |
| GnuTLS | Yes | Yes | No | No | No |
| JSSE | No | No | Yes | No | No |
| LibreSSL | No | No | No | No | No |
| MatrixSSL | No | No | No | Yes | Yes |
| Mbed TLS | No | No | No | No | No |
| NSS | No | No | No | No | No |
| OpenSSL | Yes | Yes | No | No | Yes |
| Rustls | No | Yes | No | No | No |
| Schannel | No | No | Yes | No | No |
| Secure Transport | No | No | No | Yes | No |
| wolfSSL | Yes | Yes | Partial | No | Yes |
| Erlang/OTP SSL application | No | No | No | No | Yes |
| Implementation | /dev/crypto | af_alg | Windows CSP | CommonCrypto | OpenSSL engine |

## Cryptographic module/token support

| Implementation | TPM support | Hardware token support | Objects identified via |
| Botan | Partial | PKCS #11 | |
| BSAFE SSL-J | No | No | |
| cryptlib | No | PKCS #11 | User-defined label |
| GnuTLS | Yes | PKCS #11 | RFC 7512 PKCS #11 URLs |
| JSSE | No | PKCS11 Java Cryptography Architecture, Java Cryptography Extension | |
| LibreSSL | Yes | PKCS #11 (via 3rd party module) | Custom method |
| MatrixSSL | No | PKCS #11 | |
| Mbed TLS | No | PKCS #11 (via libpkcs11-helper) or standard hooks | Custom method |
| NSS | No | PKCS #11 | |
| OpenSSL | Yes | PKCS #11 (via 3rd party module) | RFC 7512 PKCS #11 URLs |
| Rustls | No | Microsoft CryptoAPI | Custom method |
| Schannel | No | Microsoft CryptoAPI | UUID, User-defined label |
| Secure Transport | | | |
| wolfSSL | Yes | PKCS #11 | |
| Implementation | TPM support | Hardware token support | Objects identified via |

## Code dependencies

| Implementation | Dependencies | Optional dependencies |
| Botan | C++20 | SQLite zlib (compression) bzip2 (compression) liblzma (compression) boost trousers (TPM) |
| GnuTLS | libc nettle gmp | zlib (compression) p11-kit (PKCS #11) trousers (TPM) libunbound (DANE) |
| JSSE | Java | |
| MatrixSSL | none | zlib (compression) |
| MatrixSSL-open | libc or newlib | |
| Mbed TLS | libc | libpkcs11-helper (PKCS #11) zlib (compression) |
| NSS | libc libnspr4 libsoftokn3 libplc4 libplds4 | zlib (compression) |
| Rustls | rust core library | rust std library zlib-rs (compression) brotli (compression) ring (cryptography) aws-lc-rs (cryptography) |
| OpenSSL | libc | zlib (compression) brotli (compression) zstd (compression) |
| wolfSSL | None | libc zlib (compression) |
| Erlang/OTP SSL application | libcrypto (from OpenSSL), Erlang/OTP and its public_key, crypto and asn1 applications | Erlang/OTP -inets (http fetching of CRLs) |
| Implementation | Dependencies | Optional dependencies |

## Development environment

| Implementation | Namespace | Build tools | API manual | Crypto back-end | OpenSSL compatibility Layer |
| Botan | Botan::TLS | Makefile | Sphinx | Included (pluggable) | No |
| Bouncy Castle | org.bouncycastle | Java Development Environment | Programmers reference manual (PDF) | Included (pluggable) | No |
| BSAFE SSL-J | com.rsa.asn1 com.rsa.certj com.rsa.jcp com.rsa.jsafe com.rsa.ssl com.rsa.jsse | Java class loader | Javadoc, Developer's guide (HTML) | Included | No |
| cryptlib | crypt* | makefile, MSVC project workspaces | Programmers reference manual (PDF), architecture design manual (PDF) | Included (monolithic) | No |
| GnuTLS | gnutls_* | Autoconf, automake, libtool | Manual and API reference (HTML, PDF) | External, libnettle | Yes (limited) |
| JSSE | javax.net.ssl sun.security.ssl | Makefile | API Reference (HTML) + JSSE Reference Guide | Java Cryptography Architecture, Java Cryptography Extension | No |
| MatrixSSL | matrixSsl_* ps* | Makefile, MSVC project workspaces, Xcode projects for OS X and iOS | API Reference (PDF), Integration Guide | Included (pluggable) | Yes (Subset: SSL_read, SSL_write, etc.) |
| Mbed TLS | mbedtls_ssl_* mbedtls_sha1_* mbedtls_md5_* mbedtls_x509* ... | Makefile, CMake, MSVC project workspaces, yotta | API Reference + High Level and Module Level Documentation (HTML) | Included (monolithic) | No |
| NSS | CERT_* SEC_* SECKEY_* NSS_* PK11_* SSL_* ... | Makefile | Manual (HTML) | Included, PKCS#11 based | Yes (separate package called nss_compat_ossl) |
| OpenSSL | SSL_* SHA1_* MD5_* EVP_* ... | Makefile | Man pages | Included (monolithic) | — |
| Rustls | rustls:: | cargo | API reference and design manual | Two options included (pluggable) | Yes (subset) |
| wolfSSL | wolfSSL_* CyaSSL_* SSL_* | Autoconf, automake, libtool, MSVC project workspaces, XCode projects, CodeWarrior projects, MPLAB X projects, Keil, IAR, Clang, GCC, e2Studio | Manual and API Reference (HTML, PDF) | Included (monolithic) | Yes (about 60% of API) |
| Implementation | Namespace | Build tools | API manual | Crypto back-end | OpenSSL compatibility layer |
* ^ ASN.1 manipulation classes
* ^ Cert-J proprietary API
* ^ Certificate Path manipulation classes
* ^ Crypto-J proprietary API, JCE, CMS and PKI
* ^ SSLJ proprietary API
* ^ JSSE API

## Portability concerns

| Implementation | Platform requirements | Network requirements | Thread safety | Random seed | Able to cross-compile | No OS (bare metal) | Supported operating systems |
| Botan | C++11 | None | Thread-safe | Platform-dependent | Yes | | Windows, Linux, macOS, Android, iOS, FreeBSD, OpenBSD, Solaris, AIX, HP-UX, QNX, BeOS, IncludeOS |
| BSAFE SSL-J | Java | Java SE network components | Thread-safe | Depends on java.security.SecureRandom | Yes | No | FreeBSD, Linux, macOS, Microsoft Windows, Android, AIX, Solaris |
| cryptlib | C89 | POSIX send and recv. API to supply your own replacement | Thread-safe | Platform-dependent, including hardware sources | Yes | Yes | AMX, BeOS, ChorusOS, DOS, eCos, FreeRTOS/OpenRTOS, uItron, MVS, OS/2, Palm OS, QNX Neutrino, RTEMS, Tandem NonStop, ThreadX, uC/OS II, Unix (AIX, FreeBSD, HPUX, Linux, macOS, Solaris, etc.), VDK, VM/CMS, VxWorks, Win16, Win32, Win64, WinCE/PocketPC/etc, XMK |
| GnuTLS | C89 | POSIX send and recv. API to supply your own replacement. | Thread-safe, needs custom mutex hooks if neither POSIX nor Windows threads are available. | Platform dependent | Yes | No | Generally any POSIX platforms or Windows, commonly tested platforms include Linux, Win32/64, macOS, Solaris, OpenWRT, FreeBSD, NetBSD, OpenBSD. |
| JSSE | Java | Java SE network components | Thread-safe | Depends on java.security.SecureRandom | Yes | | Java based, platform-independent |
| MatrixSSL | C89 | None | Thread-safe | Platform dependent | Yes | Yes | All |
| Mbed TLS | C89 | POSIX read and write. API to supply your own replacement. | Threading layer available (POSIX or own hooks) | Random seed set through entropy pool | Yes | Yes | Known to work on: Win32/64, Linux, macOS, Solaris, FreeBSD, NetBSD, OpenBSD, OpenWRT, iPhone (iOS), Xbox, Android, eCos, SeggerOS, RISC OS |
| NSS | C89, NSPR | NSPR PR_Send and PR_Recv. API to supply your own replacement. | Thread-safe | Platform dependent | Yes (but cumbersome) | No | AIX, Android, FreeBSD, NetBSD, OpenBSD, BeOS, HP-UX, IRIX, Linux, macOS, OS/2, Solaris, OpenVMS, Amiga DE, Windows, WinCE, Sony PlayStation |
| Rustls | Rust (programming language) | None | Thread-safe | Platform dependent | Yes | Yes | All supported by Rust (programming language) |
| OpenSSL | C89 | None | Thread-safe | Platform dependent | Yes | No | Unix-like, DOS (with djgpp), Windows, OpenVMS, NetWare, eCos |
| wolfSSL | C89 | POSIX send and recv. API to supply your own replacement. | Thread-safe | Random seed set through wolfCrypt | Yes | Yes | Win32/64, Linux, macOS, Solaris, ThreadX, VxWorks, FreeBSD, NetBSD, OpenBSD, embedded Linux, Yocto Project, OpenEmbedded, WinCE, Haiku, OpenWRT, iPhone (iOS), Android, Nintendo Wii and Gamecube through DevKitPro, QNX, MontaVista, NonStop, TRON/ITRON/μITRON, eCos, Micrium μC/OS-III, FreeRTOS, SafeRTOS, NXP/Freescale MQX, Nucleus, TinyOS, HP/UX, AIX, ARC MQX, Keil RTX, TI-RTOS, uTasker, embOS, INtime, Mbed, uT-Kernel, RIOT, CMSIS-RTOS, FROSTED, Green Hills INTEGRITY, TOPPERS, PetaLinux, Apache mynewt |
| Implementation | Platform requirements | Network requirements | Thread safety | Random seed | Able to cross-compile | No OS (bare metal) | Supported operating systems |