Here is a brief description of all of them:
(c) 2013-2016 by Mega Limited, Auckland, New Zealand
This SDK brings you all the power of our client applications and let you create your own or analyze the security of our products.
License: Simplified (2-clause) BSD License.
Copyright (C) 1998 - 2016, Daniel Stenberg, daniel@haxx.se, et al.
The multiprotocol file transfer library
License: MIT/X derivate license
https://curl.haxx.se/docs/copyright.html
Copyright (c) 1995-2013 by Wei Dai. (for the compilation) and public domain (for individual files)
Crypto++ Library is a free C++ class library of cryptographic schemes.
License: Crypto++ Library is copyrighted as a compilation and (as of version 5.6.2)
licensed under the Boost Software License 1.0, while the individual files in the compilation are all public domain.
Copyright (c) 1998-2016 The OpenSSL Project. All rights reserved.
A toolkit implementing SSL v2/v3 and TLS protocols with full-strength cryptography world-wide.
License: OpenSSL License
https://github.com/openssl/openssl/blob/master/LICENSE
SQLite is an in-process library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine.
License: Public Domain
http://www.sqlite.org/copyright.html
Copyright (c) 2013-2017 Frank Denis
Sodium is a modern, easy-to-use software library for encryption, decryption, signatures, password hashing and more.
License: ISC License
https://github.com/jedisct1/libsodium
Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
A fast JSON parser/generator for C++ with both SAX/DOM style API
License: MIT License
https://github.com/miloyip/rapidjson
Copyright (c) 2011, The WebRTC project authors. All rights reserved.
WebRTC is a free, open project that provides browsers and mobile applications with Real-Time Communications (RTC) capabilities via simple APIs. The WebRTC components have been optimized to best serve this purpose.
License: BSD 3-Clause License
Copyright (c) 2017 The Qt Company Ltd.
QT is framework for cross-platform develppment, used by the Qt Example app.
License: Open Source + Commercial